Urban Forest Strategic Plan (2018)Our Trees. Our Legacy.
CITY OF BOULDER
URBAN FOREST STRATEGIC PLAN
Boulder Parks & Recreation
“The planting of a tree, especially one of the
long-living hardwood trees, is a gift which
you can make to posterity at almost no cost
and with almost no trouble, and if the tree
takes root it will far outlive the visible effect
of any of your other actions, good or evil. ”
- George Orwell
Prepared For:
City of Boulder
3198 N. Broadway
Boulder, CO 80304
Phone: 303-413-7200
BoulderForestry.org
Prepared By:
Davey Resource Group, Inc.
6005 Capistrano Ave. Suite A
Atascadero, California 93422
Phone: 805-461-7500
www.davey.com/drg
2018
City of Boulder
Urban Forest Strategic Plan
Our Trees. Our Legacy.
Acknowledgments
Parks and Recreation Advisory Board (PRAB) Members
Tom Klenow
Jennifer Kovarik
Tyler Romero
Mary Scott
Raj Seymour
Valerie Yates
Pamela Yugar
Past PRAB Members
Marty Gorce
Kelly Wyatt
Parks and Recreation Department Staff
Yvette Bowden, Director
Alison Rhodes, Deputy Director
Jeff Haley, Planning Manager
Paul Bousquet
Tina Briggs
Margo Josephs
Christy Spielman
Denise White
Forestry Staff
Kathleen Alexander
Pat Bohin
Ken Fisher
John Marlin
Tom Read
Other Department Staff
Rella Abernathy
Jessica Andersen
Ward Bauscher
Joanna Crean
Greg Guibert
Elizabeth Judd
Brett KenCairn
Valerie Matheson
MaryAnn Nason
Candice Owen
Carey Sager
Gerrit Slatter
Chris Wanner
Community Working Group
Kai Abelkis
Elizabeth Black
Roland Boller
Mikl Brawner
David Davia
M Essa
Dave Kalyan
Paul Lander
Josh Morin
Brian Muir
Keith Wood
City Council Members
Suzanne Jones, Mayor
Jill Adler Grano
Aaron Brockett, Mayor Pro Tem
Cindy Carlisle
Mirabai Kuk Nagle
Lisa Morzel
Sam Weaver
Bob Yates
Mary Young
Past City Council Members
Matthew Appelbaum
Jan Burton
Andrew Shoemaker
PLAY Boulder Foundation
Mike Conroy
Kelly Wyatt
Tyler Romero
Margo Josephs
Yvette Bowden
Caitlin Berube-Smith
City Manager’s Office
Jane Brautigam, City Manager
Mary Ann Weideman , Deputy City Manager
Tanya Ange , Deputy City Manager
Consultants
Davey Resource Group
Two Forks Collective
Accepted by the Parks and Recreation Advisory Board on June 4, 2018
Presented to City Council as an Information Packet on June 6, 2018
Table of Contents
What Do We Have? 3
What Do We Want? 4
How Do We Get There? 5
How Are We Doing? 5
Services of Urban Trees & Canopy Cover 8
Health & Wellness 9
Reducing Atmospheric Carbon 10
Improving Air Quality 11
Capturing Stormwater Runoff
& Improving Water Quality 13
Benefits to Wildlife 15
Aesthetic & Socio-economic Services 16
Lessening Energy Demand 17
Community 19
What is the Urban Forest? 21
History of Urban Forestry in Boulder 23
Guiding Principles & Regulatory Framework 25
Boulder’s Urban Forest Resource 44
City Forestry Programs & Operations 55
Threats to the Urban Forest 85
Conclusion 95
Community Input 97
Case Studies 116
Conclusion 116
Goals, Priorities, Actions 117
Plan 119
Manage 121
Protect 127
Engage 131
Monitoring & Measuring Results 137 References 139
Methodology 143
Funding 145
Calculating Individual Tree Services 147
Public Survey 147
Survey Graphs 149
Table of Figures 163
Dictionary 164
Soil Volume & Tree Stature 165
Alternative Planter Design 166
Standard Tree Planting Detail 169
Executive Summary Introduction What Do We Have?What Do We Want?
How Do We Get There?How Are We Doing?Appendix
1 7 19 97
117 137 139
EXECUTIVE SUMMARY1
What Do
We Have?
How Are
We Doing?
What Do
We Want?
How Do We
Get There?
“The city will support, promote and, in some
cases, regulate the protection of healthy existing
trees and the long term health and vitality of
the urban forest in the planning and design of
public improvements and private development.
The city will encourage overall species diversity,
native and low water demand tree species
where appropriate.”
– Boulder Valley Comprehensive Plan
Boulder is a thriving community which consistently ranks
among the best places to live in America. Resources
from Forbes to Gallup sing Boulder’s praises; beautiful
natural scenery, a robust economy, and the healthy
lifestyle of Boulder residents. Boulder is home to many
PhDs as well as numerous startups and corporate giants
including Google, Microsoft, and Threadless. It’s also a
major government research hub, home to the National
Center for Atmospheric Research and the National
Institute of Standards and Technology.
Pristine natural surroundings offer easy access to
mountain streams and lush forests. With more than 43,000
acres of open space, 151 miles of trails, 60 parks, and
the Boulder Creek Path, which runs through the middle
of town, this outdoor paradise promotes access to year-
round recreation, including hiking, fishing, biking, and
rock climbing. The community enjoys delicious local
cuisine and farm-to-table eateries. Boulder’s population
has one of the lowest obesity rates (12.4%) of American
cities (Riffkin, 2014), rated 10th in the 2016 overall
Community Well-Being Rankings (Gallup-Healthways),
and has been the nation’s fittest community since 2009.
Boulder residents strongly support environmental
protections. In 2013, Boulder became one of the first
32 cities chosen to participate in 100 Resilient Cities
(100RC). Resilience is the ability to prepare for and
respond effectively to stress. Resilient communities
pledge to preserve the quality of life today and
improve their legacy for future generations. By any
metric, Boulder is a premier city with beautiful natural
amenities, strong environmental values, and a quirky
yet highly-skilled workforce. In sum, the people of
Boulder are healthy, motivated, and educated. Urban
trees support the active, outdoor lifestyle of residents.
An urban forest is the collection of trees that grow within
a city or town. A resilient urban forest supports the
resilience of the community. Stewardship of Boulder’s
urban forest is an important part of the resilience strategy.
Boulder’s urban forest currently provides an overall
average canopy cover of 16% (2,773 acres) (Urban Tree
Canopy Assessment, 2015) and includes approximately
650,000 trees on public and private land. Along with
their aesthetic and socio-economic contribution, trees
serve as a buffer to many environmental stressors by
providing cooling shade, energy savings, cleaner air,
wildlife habitat, and vital protection for creeks and
streams by reducing stormwater runoff.
The Urban Forest Strategic Plan (UFSP) provides long-
term management goals for increasing community
safety and preserving and improving the health, value,
and environmental benefits of this natural resource. The
structure of the UFSP are based on the understanding of
what we have, what we want, how we get there, and
how we are doing. This structure, referred to as adaptive
management, is commonly used for resource planning
and management (Miller, R.W.) and provides a good
conceptual framework for urban forest programming.
EXECUTIVE
SUMMARY
EXECUTIVE SUMMARY 2Map 1: Land Cover
Canopy
16%
Impervious
33%
Pervious
47%
Water
4%
Chart 1: Land Cover
Table 1: Land Cover Classes
Land Cover Class Acres Percent
Canopy 2,773 16%
Impervious 5,724 33%
Pervious 8,198 47%
Water 755 4%
Total 17,450 100%
EXECUTIVE SUMMARY3
The development process for the UFSP involved a
comprehensive review and assessment of:
• Existing urban forest resources, including
composition, value and environmental benefits;
• Community vision, including those expressed by
the Boulder Valley Comprehensive Plan, Boulder
Resiliency Plan and Boulder Climate Action Plan;
• Guiding documents, including ordinance and
tree protection policies, development and
construction standards, and preservation
requirements; and
• Forestry operations, including funding and
current service levels for both in-house and
contracted forestry staff.
The review process established that Boulder has built
a strong foundation for an exceptional urban forestry
program. The community has made an outstanding
commitment to planting, preserving and promoting
the care of trees and other natural resources. Much
of Boulder’s urban forest, including approximately
650,000 trees and 2,773 acres of canopy, is located on
private property. The overall urban forest tree canopy
is providing more than $876,000 in annual benefits to air
quality, carbon sequestration, and avoided stormwater
runoff (Urban Forest Resource Analysis, 2015).
In addition to 600,000 privately owned trees, nearly
50,800 community trees are located on streets, parks,
and public Right-of-Way (ROW) (Urban Forest Resource
What Do We Have?Analysis, 2015). These city-managed trees are providing
approximately 24 percent of all canopy cover (4 percent
of overall Boulder acreage)and nearly $5.2 million
each year in environmental services ($700,000) and
increased property values ($4.5 million). To replace this
public resource with trees of a similar size and species
would cost nearly $110 million (Urban Forest Resource
Assessment, 2015).
Boulder’s Forestry Division exemplifies professionalism
in their dedication to high-level standards in the
management of the urban forest. The division employs
seven full-time professionals who regularly participate
in training and industry events to stay abreast of current
advancements. They are dedicated to increasing the
sustainability and resilience of the urban forest.
Forestry operations are robust and focused on best
management practices (BMPs), emerging industry
solutions, and the prudent application of available
resources. In addition to standard services, like
rotational pruning, tree removal and replacement,
storm response, development review, and responding to
customer service requests, Boulder’s forestry operations
include several exemplary programs that meet or exceed
industry recommendations These programs include a
Tree Safety Inspection Program (TSIP), Integrated Pest
Management (IPM), wood debris management and an
arborist licensing program.
Since 2013, the personnel, training, equipment and
budget to support these activities have not kept pace,
leading to longer pruning cycles, delayed responses and
deferred maintenance.
The unique climate of the Front Range poses many
challenges to the growth and survival of trees. At an
elevation of 5,430 feet, there are few native tree species
in this high desert region. Those trees that have been
naturalized and cultivated in Boulder’s urban forest face
a constant barrage of threats, including temperature
extremes, late spring freezes, snowstorms, flooding and
drought.
Boulder was the first city in Colorado to identify the
presence of emerald ash borer (EAB). This devastating
pest is 100 percent deadly to untreated ash trees. EAB
is responsible for the death of hundreds of millions
of trees in more than 30 states. Ash trees account for
more than 25 percent of Boulder’s urban tree canopy
and provide a significant contribution o environmental
and socio-economic services to the community. It is
estimated that there are more than 70,000 ash trees in
Boulder, valued at approximately $18 million (including
public, private and naturalized sites).
Since the identification of EAB in 2013, Boulder Forestry
has been at the forefront of the state’s EAB management
program. Over the next two to five years, EAB will have
a significant direct budgetary impact on Boulder and
private residents. Although Boulder Forestry is providing
pesticide treatments for many larger established ash
trees, all untreated ash are expected to die from EAB over
the next five years. As a result, Boulder is anticipating
a 25 percent loss in existing tree canopy (with as much
as 32 percent loss in some neighborhoods).
EXECUTIVE SUMMARY 4
Urban Forest Tree Population
Number of All Trees 650,000
Average Trees Per Acre 37.2
Tree Canopy Cover (Public and Private Trees)
Overall Canopy Cover 15.9%
Impervious Surfaces 32.8%
Maximum Urban Tree Canopy 40.7%
Annual Services (Public and Private Trees)
Avoided Stormwater Runoff $177,016
Carbon Dioxide Reduced $676,508
Air Quality Improvement $22,631
Total Annual Services $876,155
Long-Term Benefits (Public and Private Trees)
Stored Carbon $17,056,868
Public Tree Resource Tree Population
50,800
$109,955,170
Species Diversity (Public Trees)
235
50.7%
1
Aesthetic Benefits (Public Trees)
Property Value Increase $4,493,582
Boulder's Urban Forest
Boulder's Public Tree Resource
Species Exceeding Recommended 10%
Prevalance of Top Ten Species
Replacement Value of Public Trees
Number of Unique Species
Number of Public Trees (2015)
In addition to forestry staff, there are multiple
stakeholders, internal and external, who play a role
in the planning, design, care and advocacy of the
urban forest. The development of the UFSP included
considerable outreach to engage and collaborate with
forestry professionals, city leadership and the community.
Outreach included surveys, pop-up Tree Story Stations,
a public open house, interviews with managing
stakeholders, and technical working group meetings.
Everyone who participated played a role and provided
input for the development of the UFSP.
Overwhelmingly, stakeholders expressed the desire to
preserve and grow tree canopy. While the reasons were
varied, most participants recognize and appreciate the
environmental services and contribution to the quality
of life that the urban forest provides.
Many participants were aware of EAB and that trees are
being removed as a result. Yet most respondents were
not aware of the extent and gravity of the issue that is
expected to result in the loss of 25 percent (~775 acres)
of existing tree canopy.
Recognizing that the transformed canopy will have
a considerable economic, social and environmental
impact for decades to come, the UFSP suggests a goal
of no-net-loss in overall tree canopy by 2037.
What Do We Want?Realizing this goal will require a consolidated effort
from the community, actions include:
• Engaging and preparing the community for
canopy loss;
• Developing citywide and neighborhood planting
plans;
• Setting minimum requirements for species
diversity and large-stature trees;
• Planting 600 public trees each year;
• Facilitating the planting of 2,025 trees on private
property each year; and
• Monitoring canopy cover for gains and losses.
While unquestionably devastating, managing the losses
from EAB is a relatively short-term problem within the
long-term, perpetual stewardship of Boulder’s trees. An
urban forest is a dynamic resource, constantly growing
and responding to the environment and the care it
receives.
The preservation and care of existing and new trees
requires planning and sustainable resources to promote
forest health, longevity, and greater resilience over
time.
Table 2: Benchmark Values
EXECUTIVE SUMMARY5
• Plan, including a priority to establish a no-netloss
canopy goal of 16 percent by 2037. Additional
priorities and actions include monitoring canopy
cover for gains and losses, developing citywide
and neighborhood planting plans, creating design
strategies for maintaining irrigation to young
trees during drought, and establishing minimum
requirements for species diversity and large
stature trees.
• Manage, including priorities and actions to
consolidate all public tree care under Boulder
Forestry, excluding trees managed by Boulder's
Open Space and Mountain Parks (OSMP). Additional
priorities and actions include, temporarily
increasing annual planting budgets, facilitating
and incentivizing tree planting on private property,
continuing to implement the EAB response strategy,
securing dedicated and sustainable funding to
ensure that forestry operations meet community
safety expectations, requiring protections for
wildlife and critical habitat, and collaborating
with regional partners for cost-sharing and bulk
pricing.
• Protect, including an emphasis on trees as
essential infrastructure. Additional priorities
and actions include best management practices,
industry standards for tree care, strengthen
public tree protection, add protections for private
trees, revise professional standards for tree care
companies, water-efficient irrigation systems, and
an enhanced role for forestry in development and
construction projects.
The long-term success of the UFSP will be measured
through the realization of plan goals and demonstrated
through the increased value and services provided by the
urban forest. The plan identifies measurable actions,
potential partners, relative cost and desirable time
frames for priorities and actions. However, the UFSP
is intended to be a dynamic tool that can and should
be adjusted in response to available resources and
emerging opportunities. One of the greatest measures
of success for the UFSP will be its level of success in
meeting community expectations for the care and
preservation of Boulder’s urban forest.
How Do We Get There?
How Are We Doing?
• Engage, including priorities and actions to
communicate measurable and objective
information, facilitate understanding of urban
forest challenges and canopy goals, expand the
opportunities for community involvement in
activities and plan-making processes, and to
partner with the community on projects to broaden
support and funding for the urban forest.
The UFSP provides long and short-term strategies for
the next 20 years to ensure that Boulder’s urban forest
successfully aligns with the community’s vision for a
safe, sustainable, and resilient resource. Since Boulder
can only directly affect public trees, (24 percent of all
canopy cover), the plan recognizes that community
engagement is integral to success.
Recognizing this, stakeholders also identified areas of
focus for the long-term stewardship of Boulder’s urban
forest, including:
• Maintenance and preservation of existing trees on
both public and private property;
• Increased outreach and engagement with the
Boulder community;
• Opportunities for volunteers and neighborhood
leaders;
• Greater collaboration with local, regional, and
state partners; and
• Sustainable funding.
Finally, the Boulder Valley Comprehensive Plan (BVCP)
is the unifying document that communicates the
community’s vision for the future, identifies core values,
and provides departmental master plans with clear plan
components. The BVCP identifies specific values that
are particularly relevant to the urban forest including
great neighborhoods and open spaces, environmental
stewardship and climate action, physical health,
safety, and well-being, with sustainability as a unifying
framework to meet environmental, economic and social
goals. The principle of sustainability drives the overall
framework of the BVCP and the UFSP.
The UFSP identifies four goals for preserving the safety,
health, value, services, and resiliency of Boulder’s
urban forest. The goals are supported through priorities
and actions:
EXECUTIVE SUMMARY 6
Plan Manage Engage
• Develop and implement a 20-year Planting Plan for public trees to support the 16% urban tree canopy cover by 2037.
• Participate in an inter-departmental Urban Ecosystems Management Strategic planning process to integrate ecosystem protection and monitoring across urban, agricultural and wildland systems.
• Create an Urban Forest Emergency Response Plan for citywide coordination to ensure appropriate coverage and minimize risk to the public.
• Establish a dedicated, sustained funding source beyond the departmental budget for Boulder Forestry operations to increase the level of service to meet the community’s high standards.
• Expand the Public Tree Planting program to support efforts toward the goal of 16% canopy by 2037.
• Shift management responsibility for all trees in public street ROW and around public buildings under Boulder Forestry to maximize advantages in expertise and scale.
• Increase investment in proactive, preventative maintenance by exploring options to increase the frequency of pruning events for public street trees.
• Refine the Integrated Pest Management (IPM) Program to improve tree health while minimizing cost and negative impacts to ecosystems and the public.
• Streamline the Tree Safety Inspection Program (TSIP) to manage risk and minimize City exposure to claims as well as reduce the financial and logistical costs on forestry operations.
• Continue implementation of the EAB response strategy to maintain public safety, ecosystem services, and forest function in the face of unprecedented canopy loss.
• Transition to a common software Asset Management System to allow efficient forestry business processes across city work groups and provide essential baseline data for strategic forest management. • Continue to explore all wood utilization options to improve resiliency to increased cost or disappearance of any single waste stream. • Explore the expansion of the Commercial Tree Program (CTP) beyond the immediate downtown area to maintain urban tree canopy, protect property and better manage public safety issues.• Develop a staff succession plan within Forestry to encourage continual professional development and facilitate transitions in leadership to minimize disruption to operations.
• Deliver a State of the Urban Forest Report biennially for elected officials, key urban forest stakeholders, and the public.
• Provide the community with balanced and objective information to assist them in understanding the problems, alternatives and options to achieve the Boulder urban tree canopy goal.
• Partner with the community on projects to broaden knowledge, support and funding for the Boulder urban tree canopy goal.
• Develop and expand opportunities for community involvement in the commitment to achieve the Urban Tree Canopy goal.
• Involve the public on the analysis, alternatives and recommendations for further urban forestry related planning processes and potential code changes.
Protect
• Strengthen Boulder Forestry’s role in all city CIP projects to minimize damage to tree assets and canopy loss.
• Strengthen existing city requirements for trees on Public Property to increase tree protection, improve site preparation and strengthen tree species diversity requirements to maintain the urban tree canopy and increase forest resiliency.
• Strengthen existing and develop new city requirements for Private Property to increase tree protection, improve site preparation and strengthen tree species diversity requirements to maintain the urban tree canopy and increase forest resiliency. • Revise licensing requirements for all tree care companies performing tree work in Boulder to improve public safety and tree health.
PRIORITIES PRIORITIES
GOALS
INTRODUCTION7
In 2016, Boulder contracted with the Davey Resource
Group to develop an Urban Forest Strategic Plan (UFSP)
to specifically address the unique challenges and
opportunities Boulder’s urban forest will face over the
next 20 years.
Boulder's urban tree canopy cover was measured as 16
percent in 2013. Urban tree canopy cover is the layer of
leaves, branches, and stems of all trees that cover the
ground when viewed from above. A significant goal of
this Plan is to maintain Boulder’s 16 percent urban tree
canopy cover. This goal was established because the
urban forest faces many new threats, and will diminish
quickly without proactive measures.
There are approximately 650,000 trees in Boulder’s
urban forest. Of those trees, 50,800 are publicly owned
street trees and park trees. These public trees are
managed by Boulder, primarily through the Boulder
Forestry Division. In Boulder, public trees have an
appraised replacement value of over $110 million. That
figure represents the cost to replace all the public trees
with trees of comparable species, health and size.
The urban forest also includes hundreds of thousands
of trees on commercial, private and naturalized areas
throughout Boulder.
Challenges and opportunities have emerged that require
a proactive management approach and a long-term
planning strategy to preserve the health, sustainability,
and services of trees and canopy cover. The UFSP
is important because it explains the many different
policies, plans and actors that are involved in the
management of the urban forest. The UFSP strengthens
Boulder's ability to effectively provide the core forestry
management services focused on safety, emergency
response and sustainability. Cohesion between city staff
and the public is vital because successful urban forest
management demands a wide-reaching community
effort.
Who owns the 650,000 trees
in Boulder's Urban Forest?
50,800 are public.
~600,000 are private.
ALL trees contribute to the
urban tree canopy.
To achieve this 16% canopy goal, the time to
act is now. Boulder is losing tree canopy at an
alarming rate due to pests uch as EAB, severe
weather events, and urban development.
Boulder also contracted with Two Forks Collective to
coordinate community engagement during the planning
process. Davey Resource Group is comprised of experts
in arboriculture and urban forestry, and Two Forks
Collective are experts in community engagement. Both
firms are essential to the realization of Boulder’s goal
to preserve the existing citywide 16 percent urban tree
canopy cover because Boulder can only directly affect
public trees (24 percent of overall tree canopy cover).
Therefore, community buy-in must occur to impact
the remaining private trees (76 percent of overall tree
canopy cover).
Introduction
INTRODUCTION 8
Trees in the urban forest work continuously to mitigate
the effects of urbanization and development and protect
and enhance lives within the community in many ways.
Healthy trees are vigorous, producing more leaf surface
and canopy cover area each year.
The amount and distribution of leaf surface area are
the driving forces behind the urban forest’s ability to
produce services for the community (Clark et al, 1997).
Services include:
• Health and Wellness;
• Reducing Atmospheric Carbon;
• Improving Air Quality;
• Capturing Stormwater Runoff and Improving
Water Quality;
• Benefits to Wildlife;
• Aesthetic and Socio-economic Services; and
• Lessening Energy Demand.
Services of Urban
Trees & Canopy Cover
INTRODUCTION9
the role they play in reducing crime and aggressive
behavior has been recognized by sociologists.
Research shows that the greener a building’s
surroundings are, the fewer total crimes. This is
true for both property crimes and violent crimes.
Landscape vegetation around buildings can mitigate
irritability, inattentiveness, and decreased control
over impulses, all of which are well-established
psychological precursors to violence. Residents in
public housing reported 25 percent fewer domestic
crimes when landscapes and trees were planted near
their homes (Kuo, 2001).
A study of individuals living in 28 identical high-
rise apartment units found residents who live near
green spaces had a stronger sense of community,
better mental health, coped better with stress
and hardship, were less aggressive and violent and
Health and Wellness
Exposure to nature, including trees, has a healthy
impact on humans, such as reduced symptoms of
Attention Deficit Disorder (ADD), and faster recovery
from surgery (Ulrich, 1984). Additional benefits include:
• Fortification of human health;
• Reduced illness, decreased reliance on
medication, and quicker recovery from injury or
illness;
• Higher test scores;
• Increased worker productivity; and
• Reduced symptoms of ADD.
The importance of green spaces in urban areas and
managed problems more effectively than those living
away from green space (Kuo, 2001).
Besides offering children a place to play, natural settings
contribute to child development in at least four critical
areas. Children who spend time in green settings have
improved:
• Creativity;
• Imagination and cognitive function; and
• Intellect.
Children with ADD experienced reduced symptoms
when exposed to green environments and spending
time in nature (Faber, 2009).
A Potential Natural Treatment for Attention-Deficit/Hyperactivity Disorder:
Evidence From a National Study (Frances E. Kuo, and Andrea Faber Taylor)
Objectives. We examined the impact of relatively “green” or natural settings on attention-deficit/hyperactivity
disorder (ADHD) symptoms across diverse subpopulations of children.
Methods. Parents nationwide rated the aftereffects of 49 common after-school and weekend activities on
children’s symptoms. Aftereffects were compared for activities conducted in green outdoor settings versus those
conducted in both built outdoor and indoor settings.
Results. In this national, non-probability sample, green outdoor activities reduced symptoms significantly more
than did activities conducted in other settings, even when activities were matched across settings. Findings were
consistent across age, gender and income groups; community types; geographic regions; and diagnoses.
Conclusions. Green outdoor settings appear to reduce ADHD symptoms in children across a wide range of
individual, residential, and case characteristics.
INTRODUCTION 10
tree planting projects within municipalities, campuses,
and utility service areas anywhere in the United States.
Trees and forests reduce atmospheric carbon dioxide
(CO2) in two ways:
• Directly, through growth and carbon
sequestration; and
• Indirectly, by lowering the demand for energy.
Trees and forests directly reduce CO2 in the atmosphere
through growth and sequestration of CO2 in woody and
foliar biomass. Indirectly, trees and forests reduce CO2
by lowering the demand for energy and reducing the CO2
emissions from the consumption of natural gas and the
generation of electric power. In fact, the shade from a
single tree can save the same amount of energy as what
ten room-size air conditioners need to run for 20 hours
a day (Forest Service Pamphlet no. FS-363, as cited in
Sherer, 2006).
• One mature tree can absorb as much as 48
pounds CO2 annually and provides enough O2 to
support two human beings (McAliney, 1993); and
• Projections from computer simulations indicate
that 100 million mature trees in U.S. cities (three
trees for every other single-family home) could
reduce annual energy use by 30 billion kWh,
reducing nine million tons per year in carbon
dioxide emissions from power plants (Dwyer et
al., 1992).
Reducing Atmospheric Carbon
Governments are paying particular attention to climate
change and the effects of greenhouse gas (GHG)
emissions. As energy from the sun (sunlight) strikes
the earth’s surface, it is reflected back into space as
infrared radiation (heat). Greenhouse gases absorb
some of this infrared radiation and trap this heat in the
atmosphere, increasing the temperature of the earth’s
surface.
Many chemical compounds in the earth’s atmosphere
act as GHGs, including methane (CH4), nitrous oxide
(N2O), carbon dioxide (CO2), water vapor, and human-
made gases and aerosols. As GHGs increase, the amount
of energy radiated back into space is reduced, and
more heat is trapped in the atmosphere. An increase
in the average temperature of the earth and results in
changes in weather, sea levels, and land-use patterns
commonly referred to as “climate change.” In the last
150 years, since large-scale industrialization began,
the levels of some GHGs, including CO2, have increased
by 25 percent (U.S. Energy Information Administration,
2014).
The USDA Forest Service Urban Ecosystems and Social
Dynamics Program recently led the development
of an Urban Forest Project Reporting Protocol.
Incorporating methods of the Kyoto Protocol and
Voluntary Carbon Standard, the protocol establishes
methods for calculating reductions, provides guidance
for accounting and reporting, and guides urban forest
managers in developing tree planting and stewardship
projects that could be registered for GHG reduction
credits (offsets). The protocol can be applied to urban
Carbon Storage
Trees are powerful living infrastructure in their ability
to store large amounts of carbon in their wood, and
continue to add carbon as they grow. Although forests
do release some carbon dioxide from natural processes
such as respiration and decay, a healthy forest typically
stores carbon at a greater rate than it releases carbon.
INTRODUCTION11
Improving Air Quality
Trees improve air quality in five fundamental ways:
• Lessening particulate matter (e.g., dust and
smoke);
• Absorbing gaseous pollutants;
• Providing shade and transpiring;
• Reducing power plant emissions by decreasing
energy demand among buildings; and
• Increasing oxygen levels through photosynthesis.
Trees protect and improve air quality by intercepting
particulate matter (PM10), including dust, pollen, and
smoke. The particulates are filtered and held in the
tree canopy until precipitation rinses the particulates
harmlessly to the ground. Trees absorb harmful gaseous
pollutants like ozone (O3), nitrogen dioxide (NO2) and
sulfur dioxide (SO2). Shade and transpiration reduce the
formation of O3, which is created at higher temperatures.
Scientists are now finding that some trees may absorb
more volatile organic compounds (VOCs) than previously
thought (Karl, T. 2010; Science Now, 2010). VOCs are
carbon-based particles emitted from automobile
exhaust, lawnmowers and other human activities. The
Hidden Values of Landscaping demonstrates that the
Urban Tree Canopy (UTC) provides air quality services
valued at more than $500,000 in Denver and $1.7 million
to the entire Denver metro area (Johnson et al., 2017).
The Urban Tree Canopy Assessment conducted for
Boulder revealed that the Urban Tree Canopy annually
removes 278,780 pounds of particulate matter and
harmful gaseous pollutants (valued at $22,631).
INTRODUCTION 12
Removal of Air Pollutants
Cities and some natural processes produce air pollution
including smoke, dust, carbon monoxide and smog.
Poor air quality harms human and natural health.
Leaves are the primary tool trees use to remove air
pollutants.
Trees remove gaseous air pollution primarily by uptake
via leaf stomata, though some gases are removed by
the plant surface.
Once inside the leaf, gases diffuse into inter cellular
spaces and may be absorbed to form acids or react
with inner-leaf surfaces. Trees also remove pollution
by intercepting airborne particles.
During normal opening of stomate pores (above), smog
pollutants such as chlorine, sulfur dioxide and fluorides
may enter. The tree uses some of these materials as
food, and releases others into the air or soil.
In this way, trees receive vital nutrition and also help
purify the air.
INTRODUCTION13
Capturing Stormwater Runoff
Stormwater is water that occurs from precipitation
events and snow melt. Stormwater can soak into
vegetation and soil (infiltration), collect on the surface
and evaporate, or runoff and end up in nearby rivers,
streams, or other bodies of water.
Trees and forests augment traditional stormwater
management infrastructure and reduce the risk of
flooding. This protects water quality in creeks, rivers,
ponds, and lakes by reducing the impact from nonpoint
source pollutants (Matteo et. al., 2006). Specifically:
• Interception of rainfall in tree canopy reduces the
risk of flooding by slowing rainfall and providing a
greater opportunity for infiltration;
• Tree root zones, which often extend well beyond
canopy, promote infiltration of stormwater and
increase the water holding capacity of the soil; and
• Slowing rainfall and increasing infiltration
preserves soil quality by reducing erosion,
especially on slopes and bare soils.
Trees intercept rainfall in their canopy, which acts as a
mini-reservoir (Xiao et al, 1998). During storm events,
this interception reduces and slows runoff. In addition
to catching stormwater, canopy interception lessens
the impact of raindrops on barren soils. Root growth and
decomposition increase the water holding capacity and
infiltration rate of soils allowing for greater absorption
of rain and snowmelt (McPherson et al, 2002). Each of
these processes greatly reduces the flow and volume
of stormwater runoff, avoiding erosion and preventing
sediments and pollutants from entering the water.
Improving Water Quality
Urban stormwater runoff is a major source of pollution
for surface waters and riparian areas, threatening
aquatic and other wildlife as well as human populations.
Requirements for stormwater management are
becoming more stringent and costly. Reducing runoff and
incorporating urban trees in stormwater management
planning has the added benefit of reducing the cost
of stormwater management, including the expense
of constructing new facilities necessary to detain and
control stormwater as well as the cost of treatment to
remove sediment and other pollutants.
While Colorado has numerous river systems, more water
leaves the state than remains within it. More than 60
percent of naturally flowing water leaves the state
and is consumed by downstream users (Johnson et al.
2017). Of the approximately 40 percent that remains,
local landscapes only use approximately 3 percent of
all water consumed in Colorado (Johnson et al. 2017).
Extensive research conducted worldwide provides
evidence that stream degradation occurs with as
little as 10 percent impervious cover. During storms,
accumulated pollutants are quickly washed off and
rapidly delivered to aquatic systems as stormwater
runoff. In a typical small-scale storm event (0.5 inch),
highly concentrated and polluted stormwater would,
without interference, flow directly into Boulder‘s
waterways (Johnson et al., 2017). These small storms
are responsible for most of the pollutant washout, also
known as the first flush effect. Urban stormwater runoff
is the second most common source of water pollution
for lakes and estuaries and the third most common
source for rivers nationwide.
Trees in urban areas protect water quality by reducing
the amount of runoff from the more frequent but
less extreme storm events that are responsible for
most annual pollutant runoff. Infiltrating and treating
stormwater runoff on site can reduce runoff and pollutant
loads by 20 to 60 percent (Johnson et al., 2017). The
extensive fibrous root systems of trees also hold soil in
place, reducing further impacts on water quality due to
erosion.
Planting trees in and adjacent to ROW provides a
unique opportunity to increase the effectiveness of grey
and green stormwater systems. Existing stormwater
management systems are not always adequate to
accommodate runoff. When a system is overtaxed, peak
flows can blow manhole covers from the ground and back
up stormwater. Where existing systems are challenged
by common stormwater events, planting additional trees
is a cost-effective way to improve functional capacity.
To reduce pressure on existing systems and increase
capacity, cities must consider every available option,
especially using trees, to help manage stormwater.
INTRODUCTION 14
Stormwater Management
Trees and forests are a natural, cost-efficient, and
highly effective part of a stormwater management
program. Many communities are turning to trees to
help solve their stormwater issues in a more holistic
manner. Engineered and natural stormwater systems
that incorporate and take advantage of the natural
benefits provided by trees and forests are proving to
be a cost-effective and sustainable treatment method.
INTRODUCTION15
Benefits to Wildlife
Trees provide important habitats for numerous birds,
insects (including honeybees) and other animal species.
Their greatest contributions include:
• Preservation and optimization of wildlife
habitat; and
• Increase in movement corridors for wildlife.
Furthermore, trees and forest lands provide critical
habitat (for foraging, nesting, spawning, etc.) for
mammals, birds, fish and other aquatic species.
Trees can offer pollinators a valuable source of flowering
plants. By including an array of flowering trees that
provide pollen and nectar in the urban forest, honeybees
are provided with additional food sources.
Fragmentation not only causes loss of the amount of
habitat, but by creating small, isolated patches it also
changes the properties of the remaining habitat. At
some point when the larger forest is highly fragmented,
there are no longer adequate corridors for native forest
plants and wildlife. In fact, habitat fragmentation can
reduce biodiversity by 75 percent and impairs key
ecosystem functions by decreasing biomass and altering
nutrient cycles (Haddad et al., 2015).
Some urban adaptable species benefit from the mosaic
of green spaces even when “forest” wildlife species
are negatively impacted by fragmentation, such as
squirrels.
Forest Fragmentation
Wildlife corridors (left) link habitats while fragmented
forests (right) lead to a decline habitat quality.
To enhance wildlife habitat, numerous communities
have developed programs to preserve valuable existing
natural areas and to restore the habitat on degraded
lands. Restoration of urban riparian corridors and their
linkages to surrounding natural areas have facilitated
the movement of wildlife and dispersal of flora (Dwyer
et al., 1992). Usually habitat creation and enhancement
increase biodiversity and complement many other
beneficial functions of the urban forest. These findings
indicate an urgent need for conservation and restoration
measures to improve landscape connectivity, which will
reduce extinction rates and help maintain ecosystem
services (Haddad et al., 2015).
INTRODUCTION 16
Aesthetic and
Socio-economic Services
While perhaps the most difficult to quantify, aesthetic
and socio-economic services from trees may be among
their greatest contributions, including:
• Beautification, comfort and aesthetics;
• Increase in shade and privacy;
• Opportunities for recreation;
• Increased community walkability;
• Reduction in violence;
• Creation of a sense of place and history; and
• Increased property values.
Some of these services are captured as a percentage
of property values, through higher sales prices where
individual trees and forests are located. While some of
the services of forests are intangible and/or difficult to
quantify (e.g., the impacts on physical and psychological
health, crime, and violence), studies provide empirical
evidence that these services do exist (Kaplan, 1989;
Ulrich, 1986). There is limited knowledge about the
physical processes at work, and their interactions make
quantification imprecise. In addition, trees and forests
have positive economic services for retailers. There
is documented evidence that trees promote better
business by stimulating more frequent and extended
shopping and a willingness to pay more for goods and
parking (Wolf, 2007).
Trees also increase public and private property values.
Every dollar invested in a residential landscape yields a
$1.35 (135%) return for property values (Johnson et al.
2017). A high to excellent quality landscape is estimated
to increase property values as much as 10 percent.
Research has shown a 7 percent higher rental rate for
commercial offices having high quality landscaping.
Especially well-kept large street trees add a 3-15
percent value to a home and continue to appreciate in
value over time (Johnson et al. 2017).
INTRODUCTION17
Lessening Energy Demand
Urban trees and forests modify climate and conserve
energy in three principal ways:
• Producing shade for dwellings and hardscape
reduces the energy needed to cool the building
with air conditioning (Akbari et al., 1997);
• Tree canopies engage in evapotranspiration,
which leads to the release of water vapor from
tree canopies and cools the air (Lyle, 1996); and
• Trees in dense arrangements may reduce mean
wind speed and solar radiation below the top of
the tree canopy by up to ~90 percent compared
to open areas (Heisler and DeWalle 1988).
An urban heat island (UHI) is an urban area or
metropolitan area that is significantly warmer than its
surrounding rural areas due to human activities.
Trees reduce energy use in summer by cooling the
surrounding areas and shading-built environments.
Shade from trees reduces the amount of radiant
energy absorbed and stored by hardscapes and other
impervious surfaces, thereby reducing the heat island
effect, a term that describes the increase in urban
temperatures in relation to surrounding locations.
Transpiration releases water vapor from tree canopies,
which cools the surrounding area. Evapotranspiration,
alone or in combination with shading, can help reduce
peak summer temperatures by 2–9 degrees Fahrenheit
(1–5 degrees Celsius) (Huang et al., 1990). The
energy-saving potential of trees and other landscape
vegetation can mitigate urban heat islands directly
by shading heat-absorbing surfaces, and indirectly
through evapotranspirational cooling (McPherson, 1994).
Studies on the heat island effect show that temperature
differences of more than 9 degrees Fahrenheit (5 degrees
Celsius) have been observed between city centers
without adequate canopy cover and more vegetated
suburban areas (Akbari et al, 1997).
Trees also reduce energy use in winter by mitigating
heat loss. Trees reduce wind speeds by up to 50 percent
and influence the movement of warm air and pollutants
along streets and out of urban canyons. By reducing air
movement into buildings and against conductive surfaces
(e.g., glass and metal siding), trees reduce conductive
heat loss from buildings, translating into potential annual
heating savings of 25 percent (Heisler, 1986).
Three trees properly placed around the home can save
$100-$250 annually in energy costs. Shade from trees
significantly mitigates the urban heat island effect –
tree canopies provide surface temperature reductions
on wall and roof surfaces of buildings ranging from 20-
45 degrees and temperatures inside parked cars can be
reduced by 45 degrees. Reducing energy use has the
added bonus of reducing carbon dioxide (CO2) emissions
Trees reduce energy use in
buildings by creating shade
and evapotranspiring in the hot
summer months.
Trees also reduce energy use
in buildings by blocking cold
winter winds.
INTRODUCTION 18
Block Hot Summer Sun
Trees lower energy demand in summer by providing
shade to the built environment (Figure 1). Because
there are many different tree species, trees with
appropriate sizes, densities, and shapes are available
for almost any shading situation. Trees also provide
shade for windows that would otherwise receive
direct sunlight. This lower energy demand means that
less energy is consumed from the power plant and less
pollution is created (Figure 2).
Block Cold Winter Winds
Winds make winter cold significantly worse. Trees
can block the chilling effects of winter winds to keep
a house warmer in winter. The most effective way
is to plant a windbreak, a band of evergreen and
deciduous trees and shrubs located perpendicular to
the prevailing winds. The best windbreaks block the
wind close to the ground as well as higher up.
Evapotranspiration
Trees cool the air through a process called
evapotranspiration.
Evapotranspiration is the combination of two
processes which occur simultaneously: evaporation and
transpiration. Both of these processes release moisture
into the air and lower surrounding temperatures.
This means that buildings near trees experience
cooler temperatures and require less energy for air
conditioning.
Figure 1: Cooling Effect of Tree Shade (Balogun et al., 2014)Figure 2: Impact of Trees and Vegetation (Akbari, 2002)
WHAT DO WE HAVE?19
Boulder is located 25 miles northwest of Denver,
Colorado, in Boulder Valley where the Rocky Mountains
meet the Great Plains. To the west, iconic sandstone
slabs of the Flatirons provide a scenic backdrop and
multiple recreational opportunities.
The environment plays a significant role in urban
forestry. The elevation, precipitation rates, temperature
extremes and soil condition all affect what tree species
grow, how they grow and levels of stress. At an altitude
of 5,430 feet above sea level, Boulder is considered the
high desert.
The climate is dry to semi-arid, typical for much of the
Front Range. The high elevation fosters a mild climate
with very little humidity in the summer and winter
months. The warmest month is July with an average
daytime temperature of 87 degrees Fahrenheit. January
is the coldest month in Boulder, with an average daytime
high of 45 degrees Fahrenheit. Boulder receives an
annual average rainfall of 21 inches and snowfall of
89 inches. Precipitation patterns are influenced by the
Flatirons' rain shadow effect, which dries the air as it
passes over the Front Range.
Historically, Boulder had very few trees. Originally the
area was a largely treeless plain. In 1871, a tree-planting
program as initiated which established the beginning of
Boulder's urban forest (University of Colorado, 2018).
As of 2017, Boulder had approximately 46,094 housing
units, 108,707 residents, and 100,148 jobs. About 30,000
students attend the University of Colorado (CU). Over
the next 25 years, the area is projected to add about
6,500 housing units, 19,000 residents and 19,000 jobs.
CU student enrollment could increase by a range of
5,000 to 15,000 additional students by 2030. Boulder's
population is expected to continue the trend of growth
(Table 3).
Outdoor recreation activities abound in and near
Boulder, including biking, hiking, rock climbing, and
snow sports. Boulder manages over 45,000 acres of
land, including 151 miles of trails within the Open
Space and Mountain Parks Department, and more than
60 city parks, including sports fields, playgrounds,
neighborhood parks and community gardens.
The people of Boulder value nature and personal health.
Outdoor camps and organized recreation activities are
popular with community members. Since 2009 Boulder
has been the nation’s fittest community, with only 12.4
percent of residents reported to be obese (Gallup-
Healthways Wellbeing Index, 2016).
Boulder has earned a reputation for working proactively
to reduce the city’s environmental impacts with
established city programs to:
• Combat climate change;
• Reduce energy waste;
• Promote the health of urban farming and natural
ecosystems;
• Support the production of local foods;
• Reduce, recycle and compost waste, with an aim
of zero waste;
• Conserve water and maintain water quality; and
• Reduce the use of pesticides on public property.
The community’s outdoor lifestyle, environmental
stewardship and high quality of life make Boulder
an attractive location for established and emerging
businesses.
The city has a culture of innovation and entrepreneurial
support that helps businesses thrive, and the University
of Colorado Boulder (CU) hosts more than a dozen
federal research labs and growing companies in a variety
Community
What Do We
Have?
WHAT DO WE HAVE?20
Rent (52%)
Own (48%)
Year Population
1870 343
1880 3,069
1890 3,330
1900 6,150
1910 9,539
1920 11,006
1930 11,223
1940 12,958
1950 19,999
1960 37,718
1970 66,870
1980 76,685
1990 86,098
2000 94,213
2010 97,385
2014 105,112
of industries. Boulder has an identity as a welcoming
and inclusive community with a culture of creativity
and innovation. The city actively supports businesses
through the Economic Vitality Program, which provides
information and assistance to Boulder companies.
Boulder is frequently recognized for its quality of life as
well as its business climate. Recent accolades include
no. 1 Best Community for Physical Well-Being, no. 1 Most
Active City in the U.S., and no. 4 Best City to Launch a
Startup in 2016 (Bouldercolorado.gov). Through these
traits and actions, it is clear that Boulder is a community
dedicated to resilience.
Where Do People in Boulder Live?
Per the 2017 community profile, 52 percent of Boulder
residents live in rental units while 48 percent live in
housing they own. This has significant implications
for the urban forest regarding notifications. If a
street tree located adjacent to a rented property
will receive care from the city, who does the city
contact? The renter or the property owner? Both? Who
is responsible for private tree care and maintenance?
To meet this challenge, the City of Boulder tracks
this information in GIS.
Chart 2: Rent vs Own
I have a beautiful cottonwood tree in
my backyard that is very old. The tree
Was the original homestead tree. My
family has done all we can to keep
the tree healthy and alive. I feel very
spiritually attached to this tree.
~Submission to Boulder Tree Stories
Table 3: Boulder's Population
WHAT DO WE HAVE?21
What is the Urban
Forest?
Urban forests come in a variety of different shapes,
types and sizes. Urban forests include trees found in
urban parks, street trees, landscaped plazas, gardens,
creek and ditch corridors, greenways, wetlands, private
property and commercial and industrial campuses.
Urban forests, through the many ecosystem services
they provide, form a network of green infrastructure
that strengthens a community.
Boulder is nestled in a beautiful, natural setting,
surrounded by wildlife and stunning landscape. Much
of the area outside of Boulder is managed by Boulder's
Open Space and Mountain Parks. These open space
trees, located as a buffer between Boulder and nearby
development, provide many ecosystem services to the
region. These trees are part of natural forest areas,
largely outside of Boulder's city limits. As such, for the
purpose of this UFSP, the Open Space and Mountain
Parks trees are not considered part of the urban forest.
The map to the right shows tree canopy (green) across
the City of Boulder. Canopy on Open Space and Mountain
Parks properties (gray) are not managed by Boulder
Forestry.
Map 2: Canopy in Boulder and
Open Spaces and Mountain Parks
WHAT DO WE HAVE?22
The park trees and public plaza trees
found on city-owned property, such
as those around Evert Pierson Kids'
fishing pond, are the responsibility
of the Boulder Foresty. These trees
are included in the urban forest.
The urban forest includes street
trees found on tree lined avenues.
The trees in the public streets
rights-of-way are the responsibility
of Boulder Forestry.
For the purpose of the UFSP, the
many beautiful trees in the open
space and mountain parks that
surround Boulder are considered
their own separate entity. As
such, they are not included in the
calculations of ecosystem services
or urban forest metrics.
Parks and Public
Plaza Trees?
Included in the
UFSP.
Street Trees?
Included in the
UFSP.
Open Spaces and
Mountain Parks
Trees?
Not included in
the UFSP.
WHAT DO WE HAVE?23
As Boulder’s population grew from its incorporation
in 1871, city leaders developed strategies to manage
growth and preserve historic and natural resources. In
1959, Boulder voters approved the “Blue Line” city-
charter amendment, which restricted city water service
to altitudes below 5,750 feet to protect the scenic
flatirons from development.
In 1961, residents overwhelmingly voted in favor to
establish the Boulder Parks and Recreation Department
(BPRD). Today, BPRD manages more than 1,800 acres of
urban parkland.
Boulder’s dynamic climate, which includes high-speed
wind events, drought, drastic temperature drops, and
high summer temperatures, limits the palette of tree
species that can be grown in the community. In addition,
recent large-scale snow storms and unseasonable freeze
events have caused tree damage to species thought to
be adapted to the area.
Due to the unique climate of the Front Range, there are
few naturally occurring native trees, and most heritage
trees in the community are the legacy of ranches and
early settlements. Riparian areas have some native
vegetation such as cottonwoods and boxelder, but also
include substantial populations of naturalized species,
such as green ash.
Over time, community tree planting has significantly
added to the tree resource, where it is important to
acknowledge that these trees would not thrive without
Wood was used in city projects as well as being sold as
lumber, firewood, and other wood products.
By 1982, the management of DED was mostly under
control through removals, sanitation, and enforcement.
With a decrease in removals and an increasing
availability of private arboriculture services, Boulder
Forestry production staff was dismantled and replaced
by contractual labor.
By the late 1980s, Boulder had employed a city Forester
and two full-time Forestry Assistants to manage the
growing needs of the urban forest. As a result, the first
inventory of public trees was collected in 1987.
In the early 1990s, gypsy moth, another invasive tree
pest, was found and promptly controlled with a biological
control agent sprayed from helicopters in collaboration
with the Colorado State Forest Service. Around the same
time, the first tree safety inspection list was created
by a contractor due to an increasing number of tree
failures. The program continues to monitor trees.
An urban forestry modeling strategy was developed by
Boulder Forestry to quantify maintenance requirements
and costs based on species and relative age distribution.
Trees and forests go through several developmental
stages: Planting, Establishment, Growth, Structure,
Mature, Overmature, and Replacement (PEGSMOR).
Urban foresters use the concept of PEGSMOR to
understand the needs of a tree over its lifespan. Based
on the model’s projections, additional budget and
forestry staff resources were allocated to help manage
damages from storms and emerging pests and to further
enhance Boulder’s urban forest.
the care of adjacent property owners and city staff.
Because 92 percent of all trees are on private property,
it is critical that the community is educated and
motivated to provide for their trees.
In the 1970s, Dutch Elm Disease (DED), an invasive
pathogen, spread rapidly through the urban forest,
resulting in the removal of over 1,000 public elm trees.
The sudden decline of elms necessitated the first
systematic tree removal program beginning in 1972.
Following the hiring of the first city forester in 1973,
an outbreak of Mountain Pine Beetle hit in Boulder’s
open space and mountain park areas. Several in-house
crews were mobilized to address the outbreak. Once
the threat dissipated, crews transitioned to providing
care for all public street and park trees.
By 1975, Boulder Forestry had a crew of three full-time
staff as well as two field crews tasked with removing elms
and other dying street trees. A tree planting program
was established and focused on increasing the diversity
of species in the public urban forest. Staff used a city-
owned sawmill to mill logs from elm and pine removals.
History of Urban
Forestry in Boulder
WHAT DO WE HAVE?24
In 2015, the City of Boulder was identified as one of
the Rockefeller Foundation's 100 Resilient Cities. This
designation provided extra funding and resources for
the city to work with multiple community planning
organizations. Through a partnership with Trimble and
DigitalGlobe, the city developed an initial geographic
information system (GIS) land cover data layer that
identified tree canopy, water, and impervious and
pervious surfaces. Boulder has achieved Tree City USA
status from the Arbor Day Foundation for 33 years.
Today, Boulder Forestry includes seven full-time
employees; a city Forester, a Forestry Field Operations
Supervisor, three Assistant Foresters and two Forestry
Field Technicians. The division annually hires two to
three seasonal employees and is responsible for the
direct management of approximately 50,800 city park
and public street ROW trees. The division also manages
many external contractual services.
Historical Timeline
• 1961 - Residents voted in favor to
establish the Boulder Parks and Recreation
Department.
• 1973 – First city forester hired in response
to Dutch elm disease removals.
• 1975 - A tree planting program was
established and focused on increasing the
diversity of species in the public urban
forest. Staff used a city-owned sawmill to
mill logs from elm and pine removals.
• 1987 – The first inventory of city and park
trees was collected.
• 1990 – Gypsy moth, another invasive tree
pest, was found and promptly controlled
with a biological control agent (Bt) sprayed
from helicopters in collaboration with the
Colorado State Forest Service.
• 1991 - The tree safety inspection program
was created due to the number of silver
maple failures.
• 2002 – Drought conditions led to severe
stress in the urban tree population.
• 2013 – EAB Detected
• Today - Boulder Forestry includes
7 full-time employees and manages
approximately 50,800 public trees.
Damage caused by Dutch elm disease.
The tree safety inspection program (TSIP) at work.
An adult emerald ash borer.
WHAT DO WE HAVE?25
City policies and regulations provide the foundation
for the Boulder urban forestry program. They outline
requirements and specifications for the planting,
installation, and care of Boulder's public trees and
provide the regulatory framework for the protection
and preservation of the urban forest assets. In addition,
city policies and regulations provide the enforcement
framework of activities and issues that impact the
community's trees.
The development of Boulder's Urban Forest Strategic Plan
included a comprehensive review of guiding documents,
local policies, development and construction standards,
ordinances, and other regulations that apply to the
urban forest.
The following plans also had extensive outreach and
public engagement as part of their development,
ensuring they reflect community vision and preferences.
The following provides a summary of the review process
and key findings.
Boulder Valley
Comprehensive Plan
The Boulder Valley Comprehensive Plan (BVCP) provides
a general statement of the community’s desires for future
development and preservation of the Boulder Valley. The
principle of sustainability drives the overall framework
of the BVCP. Core components provide guidance for
growth and development. This guidance includes
preservation, economic development, environmental
protection, transportation, neighborhood character,
and urban design and land use.
Vision
"The Boulder Valley community honors
its history and legacy of planning for a
livable community surrounded by open
space and rural lands while striving
together to create and preserve a
truly special place that is sustainable,
resilient, equitable and inclusive – now
and for future generations."
Guiding Principles and
Regulatory Framework
Core Values
Core values represent long-standing community values
and a clear vision of Boulder’s commitment to quality
of life issues, including those supported by the Urban
Forest Strategic Plan:
• Sustainability as a unifying framework to meet
environmental, economic and social goals;
• A welcoming, inclusive and diverse community;
• Culture of creativity and innovation;
• Strong city and county cooperation;
• Our unique community identity and sense of
place;
• Compact, contiguous development and infill that
supports evolution to a more sustainable urban
form;
• Open space preservation;
• Great neighborhoods and public spaces;
• Environmental stewardship and climate action;
• A vibrant economy based on Boulder’s quality of
life and economic strengths;
• A diversity of housing types and price ranges;
• An all-mode transportation system to make
pedestrian mobility more accessible; and
• Physical health, safety and well-being.
It is important to note that although all the following
plans set goals, guidelines and priorities for forestry,
they do not provide additional funding, staff or
partnerships to accomplish them. They also do not
address what may be perceived as trade-offs, such as
more canopy could result in less opportunity for solar.
Or higher development costs for public and private
development if there are more tree requirements and
restrictions. A solid review of plan integrations with
consideration to funding and priorities is explored in
the recommendations of the UFSP but will require
departmental and community buy-in to be successful.
WHAT DO WE HAVE?26
Boulder Valley
Comprehensive Plan
Integrated Pest Management Policy (2002)
Flood and Stormwater Utility Master Plan (2004)
Urban Wildlife Plan (2006)
Boulder Parks and Recreation Master Plan (2014)
Boulder’s Climate Commitment (2017)
Resilience Strategy (2017)
Multi-Hazard Mitigation Plan (2018)
Departmental Master Plans are developed to be
consistent with the Comprehensive Plan. They establish
detailed policies, priorities, service standards, facility
and system needs and capital budgeting for the delivery
of specific services provided.
The Boulder Valley Comprehensive Plan policies guide
decisions about growth, development, preservation,
environmental protection, economic development,
affordable housing, culture and arts, urban design,
neighborhood character and transportation. The policies
also inform decisions about the manner in which urban
services are provided, such as police, fire, emergency
medical services, water utilities and flood control.
Urban Forest Strategic Plan Implications
The BVCP is the unifying document that creates a
cohesive whole from many other plans. Because of this,
all urban forest strategies and management practices
should be designed to be congruent with other plan goals.
Often, there is opportunity for synergy. For example,
the urban forest can serve as a tool to Boulder's climate
commitment through lessening energy demand.
The BVCP is built on the framework of sustainability and
resilience. A sustainable urban forest is well-managed,
designed for the long-term, and healthy. A resilient
urban forest has a diverse species composition and
proactive maintenance. To attain these sustainable and
resilient traits, Boulder must commit adequate funding
to conduct the core programs and responsibilities
necessary for optimal tree care.
WHAT DO WE HAVE?27
Key themes, which emerged from research and
community engagement, shaped the six strategies that
are the focus for the future action and decision-making
outlined in the BPRD Master Plan.
• Taking Care of What We Have
The trees of the urban forest serve as living
infrastructure for Boulder. This infrastructure
provides numerous benefits, and so the
maintenance and growth of the urban forest is
vital and embodies the BPRD theme of Taking Care
of What We Have.
BPRD Mission
"Boulder Parks and Recreation Department will
promote the health and well-being of the entire
Boulder community by collaboratively providing
high-quality parks, facilities and programs."
Vision
"A community where everyone’s health and well-
being is founded on unparalleled parks, facilities
and programs."
Boulder Parks and Recreation
Master Plan
The 2014 Boulder Parks and Recreation Department
(BPRD) Master Plan established a five-year plan to
identify short-term strategies to build success over the
long-term. The BPRD Master Plan is guided by principles
that include sustainable practices, health, partnerships,
and service excellence. A clear mission and vision
statement clarify the intent of the plan:
Case Study: Neighborhood Tree Stewards
Since 1997, the Neighborhood Tree Steward (NTS)
program has worked with Portland, Oregon community
members to provide nearly 300 people with the tools
and resources to be active leaders and urban forest
promoters in their neighborhoods. Participants enroll in
a seven-session course (21-22 hours) that covers topics
including tree biology, identification, pruning and
maintenance, proper planting techniques, ecosystem
services, pests and pathogens of the urban forest, and
urban forest management and policy. As of 2017, the
course includes an environmental justice component
to address urban forest equity. The cost to attend
is $26, which includes the NTS hoodie participants
receive on completion of the course. Participation in
all 7 courses is required, but related substitute events
can qualify as credit.
No previous experience is needed to become a
Neighborhood Tree Steward, but participants usually
have a passion for trees, a desire to learn, and
a commitment to help. The NTS curriculum has
developed over time based on feedback from student
surveys, and availability of guest speakers. Curriculum
is reviewed and updated annually. Staff from the non-
profit along with professional volunteers, teach these
courses. Once the course is completed, NTS graduates
are asked to contribute 40 hours of tree-related
volunteer service over the next year. Participants
fulfill this service requirement by participating in
urban forestry workshops, serving on the Heritage Tree
Committee, teaching kids about trees at a Learning
Landscapes event, organizing a community tree
planting, or representing Neighborhood Tree Teams at
Neighborhood Association Meetings.
Key Concepts:
• Provide opportunities for volunteers to take on
leadership roles.
• Build a team of engaged advocates.
• Understand the community’s unique urban
forestry challenges and opportunities.
• Participants use their knowledge to provide
community service and urban forest outreach.
• Develop strategies to remove barriers to
participation for all community members.
• Trainees become advocates for the urban forest
armed with knowledge of area trees, policies,
and threats.
WHAT DO WE HAVE?28
• Community Health and Wellness
The urban forest cleans the air, moderates
extreme temperature, and provides mental and
physical health benefits. A thriving urban forest
supports the BPRD theme of community health
and wellness. In addition, effective management
of the urban forest creates a safe environment for
residents and visitors.
• Financial Sustainability
Optimized maintenance programming and species
selection for trees in the urban forest will help
balance costs with returns and minimizing volatility
in budget demands. Thus, forward thinking and
proactive maintenance supports the BPRD theme
of financial sustainability.
• Building Community and Relationships
A successful urban forest and urban forestry program
builds communities and relationships in two major
ways. The first is by providing safe and desirable
spaces where the community feels relaxed to
interact with each other. The second is through
the direct involvement of community members
by bringing together numerous organizations and
individual volunteers together for planting parties,
tree nature walks, fundraising, and other urban
forestry activities.
• Youth Engagement and Activity
The urban forest provides a rich opportunity for
collaboration with school systems to educate and
engage the youth with outdoor activities. Further,
activities such as trail maintenance and tree
plantings serve as potential volunteer projects. In
addition, the urban forest provides fun, safe, and
comfortable places to play and study.
• Organizational Readiness
A key component of urban forest management is
emergency response. Improved processes, staff
training, communication, and coordination will
foster efficient organizational readiness.
WHAT DO WE HAVE?29
structure, and culture are designed and prepared
to respond to community needs.
• BPRD shall develop a highly effective workforce
that will positively impact the community’s health
and quality of life.
As part of the background research for the 2014 BPRD
Master Plan, a Needs Assessment was conducted in 2014
to analyze the existing services provided by the BPRD
to Boulder in the following areas: parkland, recreation
facilities and recreation programs and services. Agencies
• The proposed development of any new park and
facility shall be evaluated through a feasibility study
that includes a Needs Assessment, user profile,
projected participation analysis, development
funding method, life cycle cost pro forma and
alternative development trade-off analysis.
• BPRD shall seek and develop partnerships and
opportunities to leverage maintenance and capital
building funds.
• BPRD shall ensure that the department workforce,
Plan policies that are especially relevant to the
development of the Urban Forest Strategic Plan include:
• BPRD shall ensure adequate resources are available
to maintain and operate assets within community
sustainability goals.
• An asset management system that tracks; asset
condition, critical systems maintenance and
repair and rehabilitation requirements, will be
implemented and used in making park and facility
investment decisions.
Case Study: TreePhilly
Since 2012, TreePhilly, a program of the Philadelphia
Parks and Recreation Department, has provided over
17,500 trees to more than 8,000 residents. The yard
tree program was the result of a partnership with
the Fairmount Park Conservancy to provide trees for
private property plantings. The trees are distributed
to registered participants with mulch bags. The trees
stock are 5-gallon grow-bags with handles to facilitate
ease of transport and planting, and participants have
a demonstration of proper tree planting from city
arborist staff and trained volunteers at the time of
pick up. Additional information is provided through an
online video library, and through a Yard Tree Planting
and Care guide which is available for download.
Over the past six years, the program has been improved
to increase inclusion, and streamline tree procurement.
For example, Tree Philly offers free delivery and
planting for residents with limited mobility through a
simple application process which is requested wo to five
times per year. Those trees are delivered and planted
by the nursery which grows the tree stock from liners.
Since the program is within the Philadelphia Parks and
Recreation Department, tree purchasing originally
went through the city procurement office, which added
layers of complexity. Over time, staff developed a good
working relationship with a local nursery, and today,
they provide all the trees, as well as delivery to each
neighborhood event. Tree Philly Staff provides a tree
list one year in advance, and the nursery produces the
stock. The tree price is approximately $25 per tree to
the city (free to program participants).
The yard tree program is managed by one full time
employee and two seasonal (nine-month) staff.
Each event requires about 20 volunteers. Volunteer
recruitment and training is provided by the Pennsylvania
Horticultural Society Tree Tenders program. Initially,
the program was publicized through flyers, attending
community meetings and press releases. Today, most
participants find out by word of mouth. Neighbors
have begun to see tree distribution days as recurring
community events which are now an expected city
service. A brief email survey is sent to all participants
to check on the tree at the time of establishment.
Key Concepts:
• Grow canopy on private property by providing
training, mulch and free trees;
• Address concerns about city assets on private
property by securing program funding from an
outside source; and
• Requests for trees are made online and
distributed en masse at neighborhood events to
facilitate easy transport.
WHAT DO WE HAVE?30
track services as a way to meet the needs and desires
of citizens. This tracking also helps maintain a desired
state while taking land use goals, as well as limited
financial and human resources, into consideration.
The Needs Assessment analyzed parks by the four
categories defined by BPRD:
• Neighborhood parks;
• Community parks;
• City and regional parks; and
• Other land types.
Parks in Boulder have 122 acres of tree canopy. BPRD
has nearly 717 acres currently developed for public use.
Urban Forest Strategic Plan Implications
Because many urban forest trees are located in
Boulder parks, the components of this plan have many
implications for urban forest management. The key
themes addressed in the BPRD Master Plan highlight
the opportunity for community outreach and volunteer
events. Effectively sharing city resources such as
equipment and staff can help maximize departmental
goals while reducing overall city expenses. The parks
plan also facilitates the definition of departmental roles
in the management of the urban forest.
Case Study: Colorado Solar Gardens
Colorado Solar Gardens allow customers to buy shares
in a solar array, and receive annual savings. Over 20
solar gardens were built in Colorado through an Xcel
Energy Pilot program, including two in Boulder: the
Clean Energy Collective and Community Energy Solar.
In Xcel Energy’s Colorado territory, solar gardens can
be anywhere from 10 kilowatts, which would fit on a
large roof, to 2 megawatts, requiring up to 16 acres. An
average single-family home would offset 100 percent
of its electricity usage with about 2-5 kilowatts of
solar power. There are different ways to participate
in a solar garden, in one case, community members
invest up front and save on their energy bill.
One-kilowatt shares cost $3,700 and save $270 per year.
In other cases, subscribers purchase or lease shares
in a solar garden operation offered by a nonprofit,
municipality, or solar developer. The maintenance
and operation of the solar garden is provided by the
operator, and credits are distributed as reductions
in monthly Xcel Energy bills. In Colorado, at least
5 percent of solar garden subscribers must be low
income.
Recognizing that solar gardens provide a solution
to urban forest versus solar conflicts, the city can
facilitate outreach for the participation in solar
gardens. Boulder has attained the Solar Friendly
Communities recognition, which demonstrates the
city’s commitment to solar energy. Neighborhood
services provides information to residents about
opportunities to join solar gardens.
Key Concepts:
• Provide opportunities to participate in solar
energy for all, including renters and those with
homes and businesses shaded by trees;
• Maintain urban forest canopy, and place solar
arrays in appropriate facilities that are easily
maintained; and
• Reduce barriers to entry with relatively low-
cost share options.
WHAT DO WE HAVE?31
Flood and Stormwater Utility
Master Plan
Stormwater and Flood Management Utility is responsible
for the administration of the city's flood management,
stormwater quality, and stormwater drainage programs.
Because trees and canopy play a role in stormwater
management, the development of the UFSP included
consideration that outline:
• System master planning and design;
• System maintenance and restoration;
• Flood prediction;
• Stormwater quality management;
• Emergency preparedness; and
• Capital improvements and land management.
Guiding Principles
Using national and regional trends and philosophies, as
well as current and past local policies, staff recommends
five guiding principles:
• Preserve floodplains;
• Be prepared for floods;
• Help people protect themselves from flood
hazards;
• Prevent adverse impacts and unwise uses in the
floodplain;
• Seek to accommodate floods, not control them;
and
• Implications for the Urban Forest Strategic Plan.
Boulder Resilience Strategy
The Resiliency Strategy provides approaches for Boulder
to strengthen preparedness for future challenges.
These challenges include relevant shocks like flash
flooding, sudden freezes, or wildfires. The Resiliency
Plan is built on three core strategies: connecting and
preparing, partnering and innovating, and transforming
and integrating. The vision of the Resiliency Plan is:
"Building on a legacy of innovation, Boulder will
cultivate a creative spirit to adapt to and thrive in
a changing climate, economy and society."
Urban forests supply multiple cultural and ecological
services and are therefore often cited as a tool for
building urban resilience to the effects of climate
change. Urban forests reduce negative climate change
Urban Forest Strategic Plan Implications
The urban forest is a key component in flood and
stormwater management. Trees and vegetation
minimize the severity of flooding from storm events
by intercepting rainfall in the canopy. This reduces soil
erosion and improves stormwater quality.
Green infrastructure principles can be applied to tree
planter designs to minimize stormwater runoff. The
Flood and Stormwater Plan also relates to urban forest
management by defining clear departmental roles in
emergency events.
WHAT DO WE HAVE?32
impacts, enabling cities to absorb greater disturbance
while maintaining their essential structure and function
and supporting the wellbeing of residents (Hartman,
2016).
Citizen Science Project
Boulder is one of the first 32 cities chosen to participate
in 100 Resilient Cities (100RC). The program, pioneered
by the Rockefeller Foundation, is funding 100 chief
resilience officers in selected cities worldwide. 100RC
is a global network pioneered by the Rockefeller
Foundation to help cities around the world become
more resilient to the physical, social, and economic
challenges of the 21st century. Boulder joined the
network as part of the initiative’s first wave in 2013, and
through its participation, is committed to demonstrating
leadership in resilience as well as leveraging resources
and opportunities.
Urban Forest Strategic Plan Implications
Resiliency is a fundamental component of effective
urban forest management. This is accomplished through
two primary categories: preparation and response.
In preparation, tree species should be selected from
a diverse range to mitigate the potential impact of
severe weather events, pests, and other threats. For
response, clearly defining departmental roles and lines
of communication during and post emergency events
will increase service effectiveness and lower overall
response time.
WHAT DO WE HAVE?33
Multi-Hazard Mitigation Plan
The purpose of the hazard mitigation plan is to reduce
or eliminate long-term risk to people and property
from natural hazards and their effects in Boulder. The
city is vulnerable to several natural hazards that are
identified, profiled, and analyzed in the plan. Floods,
wildfires, and severe weather are some of the hazards
that can have a significant impact on the city. The plan
categorizes the urban forest as major capital assets in
Boulder.
The Multi-Hazard Mitigation Plan has three goals:
• Raise awareness of Boulder’s natural hazards;
• Reduce vulnerability to natural hazards; and
• Increase interagency coordination to reduce the
impact of natural hazards
The plan notes several areas and examples of events
that have harmed trees, including the 2002 drought
that damaged trees and resulted in unexpected pruning
and removal costs estimated at over $120,000. The
plan recommends an eight-year pruning rotation, which
would make trees stronger and more resistant to storm,
freeze, and snow damage, thus reducing post-storm
cleanup costs and liability exposure.
In addition to recognizing the environmental services
created by the urban forest, the plan also details the
valuable role the urban forest plays in flood control.
Boulder‘s urban forest reduces stormwater runoff by
approximately 12.2 million feet per two-inch storm
event (enough water to fill Folsom Field, the university‘s
football field, several times). The plan also recommends
increasing Urban Tree Canopy in commercial areas by 2
percent and in residential areas by 4 percent.
A valuable component of the plan is to make the City of
Boulder eligible for certain federal disaster assistance,
specifically, the Federal Emergency Management
Agency’s Hazard Mitigation Grant Program, Hazard
Mitigation Assistance grant program and Pre-Disaster
Mitigation program. These federal assistance programs
can be valuable resources for unexpected urban forest
challenges.
The full plan includes descriptions of actions,
identification of alternatives, responsible offices,
priority, cost estimates, estimated benefits, potential
funding sources, and schedules.
Urban Forest Strategic Plan Implications
Much like the Resiliency Plan, the Multi-Hazard Mitigation
Plan facilitates the defining of departmental roles and
lines of communication during and post emergency
events. This will increase service effectiveness and
lower overall response time.
"The trees that make up
the urban forest are also
considered major capital assets
in the city."
~Multi-Hazard Mitigation Plan
WHAT DO WE HAVE?34
The Ecosystems Action Area is relevant to the urban
forest and relates to the ability of urban, wildland,
and agricultural ecosystems to capture and stabilize
atmospheric carbon and provide critical buffering
against climatic extremes. Urban forestry priorities
include increasing the number of local trees and green
infrastructure to increase urban tree canopy for the
long-term. Key aspects of the strategy are community
education, tree plantings, supporting local green
nonprofits, and tree maintenance.
Urban Forest Strategic Plan Implications
Trees are a key component to mitigating climate change.
Trees in the urban forest are living infrastructure that
directly strengthen the city’s climate action plan. By
providing shade and blocking cold winds, trees normalize
building temperatures and reduce energy use. Trees
also absorb carbon dioxide through photosynthesis and
filter the air we breathe.
Forest Ecosystem
Management Plan
In June of 1999, Boulder City Council approved Boulder's
Forest Ecosystem Management Plan (FEMP) to manage
lands under the jurisdiction of Boulder’s OSMP. The
plan established a framework, policy guidelines, and
management direction for forest ecosystem management
on city lands. The FEMP focuses on two primary goals:
• Maintain or enhance native plant and animal
species, their communities and the ecological
processes that sustain them; and
• Reduce the wildfire risk to forest and human
communities.
Urban Forest Strategic Plan Implications
It is important to note that the OSMP trees are not
included as part of the urban forest within the context
of the UFSP. The open spaces and mountain parks form
a buffer around the city, helping to establish their own,
separate identity from neighboring communities and
provide their own set of ecosystem services. These trees
are not included when conducting Boulder’s urban forest
inventory or calculating ecosystem benefits from the
urban forest. There are still many valuable opportunities
for education and collaboration with OSMP to collect
data, conduct staff training, share information, evaluate
ecosystem services, and collaborate for education and
outreach.
"Research indicates that healthy trees can
mitigate a range of environmental impacts,
including stormwater runoff, poor air quality
and temperature extremes. Trees also
provide significant energy use reductions
associated with both cooling and heating...
...The City of Boulder’s urban forest and
ecosystems are an integral part of its living
infrastructure."
~Climate Action Plan
Climate Action Plan
Boulder’s Climate Action Plan (CAP) is a set of proactive,
city-funded programs that target the reduction of local
greenhouse gas emissions. In 2002, Boulder City Council
passed a resolution encouraging the community to
reduce its greenhouse gas emissions to levels identified
by the Kyoto Protocol. In 2009, the city’s voters became
the first in the country to pass a tax to reduce greenhouse
gas emissions and address the impact of human activity
on climate change (the CAP tax).
The four Action Areas for the 2017 city’s Climate
Commitment are:
• Energy;
• Resources;
• Ecosystems; and
• Community climate action.
WHAT DO WE HAVE?35
Boulder’s Climate Commitment
The 2017 Climate Commitment articulates the following
vision for the urban forest:
"By 2050, Boulder’s urban landscape will be planted
with trees and plants that can moderate climate
extremes, reduce energy, and water use, improve
water quality, and enhance the beauty and livability
of Boulder’s urban environment... More than 20
percent of the land area in the developed portions
of Boulder will be shaded by trees … By increasing
the number, diversity and placement of trees in
Boulder’s urban centers, we will improve air and
water quality, reduce building heating and cooling
needs, and mitigate the visible loss of hundreds of
thousands of ash trees in our community."
Urban Forest Strategic Plan Implications
The Commitment contains the following priorities:
• Maintain the existing urban tree canopy;
• Monitor the urban forest using both on-the-
ground and remote sensing technologies to
document how it is responding to climate
change. Establish ongoing monitoring protocol;
• Increase the diversity of urban tree species to
improve overall urban forest resilience;
• Review and improve strategies for pest and
disease invasions, including EAB;
• Review and refine park and natural space
plans to minimize damage from the impacts of
increased use and warmer conditions;
• Explore the establishment of a partner, non-
profit urban forest foundation to provide
additional financial and community support;
• The city and county will strive to preserve and
protect the natural resource base by:
• Maintaining and enhancing the biodiversity
and productivity of ecological systems;
• Ensuring the efficient use of natural resources
that does not deplete them over time
• Reducing and minimizing the use of non-
renewable resources; and
• Review and revise enforcement of canopy goals
and parking lot shading guidelines.
WHAT DO WE HAVE?36
Urban Wildlife Management Plan
The Urban Wildlife Management Plan (2006, 2011)
(UWMP) establishes a set of policies and procedures for
managing wildlife, including species of special concern,
within Boulder on both public and private lands. The
purpose of the UWMP is to develop effective strategies
to minimize human/wildlife conflicts and increase
public awareness of how to better coexist with these
animals.
The UWMP includes the Black Bear Component and
Mountain Lion Component, both were approved in 2011,
In addition, the Black-tailed Prairie Dog Component, was
approved in 2006. The city’s goals and the plan support
and recommend the protection of animal species, not
individual animals, and emphasize humane, non-lethal
control of wildlife whenever possible.
Urban Forest Strategic Plan Implications
By minimizing forest fragmentation, wildlife corridors
are preserved, resulting in a healthier ecosystem. It is
also important for tree care professionals to identify
when trees are currently being used as habitats. The
city limits planting of true "fruit" bearing trees, such as
pears and apples west of Broadway Avenue, since they
are a Black Bear attractant.
WHAT DO WE HAVE?37
State Law
Pesticides
The Colorado Department of Agriculture (CDA)
regulates the distribution and use of pesticides in the
state to prevent adverse impacts to the public and
the environment. Regulation includes licensing and
inspection of all commercial and private pesticide
applicators to make sure pesticide use, storage, and
disposal comply with state and federal law. CDA also
monitors pesticide sales and provides regulations for
pesticide use near waterways, which requires a state
permit (available online).
Emerald Ash Borer Quarantine
EAB is a federally quarantined pest. With the Boulder
discovery of EAB in 2013, the CDA and USDA Animal and
Plant Health Inspection Services imposed a quarantine
on Boulder County and parts of Weld, Jefferson, and
Larimer counties to slow the spread of EAB. The
quarantine prohibits the movement of hardwood,
firewood, and other ash tree stock and wood materials
outside quarantined areas.
Photo courtesy of Museum of Natural History, University of Colorado, Boulder
WHAT DO WE HAVE?38
Municipal Ordinance and Policy
TITLE 6. CHAPTER 6 PROTECTION OF TREES & PLANTS
establishes rules and regulations for the licensing of tree
care professionals, provides tree removal mitigation
requirements, and defines penalties for damage to
trees in parks and unpermitted damage to street
trees. In Boulder, all maintenance for public street
trees, including planting, rotational pruning, pesticide
applications, and removal, is the responsibility of
Boulder Forestry. Adjacent property owners have the
following opportunities and obligations:
• May contract with a licensed certified arborist
to perform tree work such as pruning or the
application of pesticides to a public street tree
with authorization from the city forester; and
• Adjacent property owners must also water public
street trees and provide a sod free base to avoid
damage.
If a property is going to be developed or redeveloped,
trees undergo a site review process including inventory,
anticipated impacts, and plans for mitigation. Street
trees are required to be planted in the public ROW at
the time of development. On most sites, the designated
spacing is one tree per forty linear feet, within ten feet
of the pavement edge. The trees must be from the
approved street tree list, or approved by staff on a case-
by-case basis if unique circumstances are identified.
The Planning Department regularly provides expert
advice to ensure species planted are compatible with
site attributes. Additional requirements for parking lots
and open spaces are defined.
TITLE 6 protects trees in the ROW and on city-owned
property, but the adjacent property owner can remove
trees in the ROW if they obtain approval. Construction
on city-owned property and public ROW and easements
must provide tree protection in conformance with
the Boulder Design and Construction Standards. To
commercially prune trees for profit, an individual would
need the proper licensing.
Code requires that when trees and plants in the ROW
are removed or destroyed they shall be replaced with
equivalent value as determined by city manager. If the
location cannot support a new, equivalent tree, then
Boulder will be reimbursed the appraised value of the
tree.
WHAT DO WE HAVE?39
TITLE 9. CHAPTER 9 LANDSCAPING AND SCREENING
STANDARDS (Development Standards) requires a
“sight triangle” where a driveway intersects a public
ROW or where property abuts the intersection of two
public ROW (unobstructed sight). Trees may be planted
and maintained within the “sight triangle” area if all
branches are trimmed to maintain a clear vision for a
vertical height of ninety-six inches above the roadway
surface and the location of the trees planted, based on
the tree species expected mature height and size, does
not obstruct sight visibility by more than twenty-five
percent of the “sight triangle".
Landscape and screening standards in TITLE 9.
CHAPTER 9 also require a minimum of one tree per
1,000 square feet for public, outdoor, and landscaped
open spaces. The trees must be planted in the ground
or accommodated in tree vaults over parking garages.
Parking lot screenings require at least one tree per 25
linear feet at property lines. There is a separate interior
planting requirement of one tree for every 200 square
feet of landscape area.
Streetscape improvements must meet several
standards:
Street Trees: A planting strip consisting of deciduous
trees shall be planted along the full length of all public
and private streets in all zoning districts. When possible,
trees shall be planted in the public ROW. Large deciduous
trees and detached sidewalks are the preferred design
elements.
Alley Trees: Except for existing single-family lots, trees
shall be planted at an overall average of one tree per
forty linear feet within ten feet of the pavement or
edge of alley.
Streetscape Requirements: Street trees must be
selected from the approved street tree list set forth in
the Boulder Design and Construction Standards, unless
an equivalent tree selection is approved by the city
manager.
Boulder has developed an excellent, flexible matrix that
communicates the required planting by the sidewalk
site conditions and traits.
WHAT DO WE HAVE?40
TITLE 9. CHAPTER 12 SUBDIVISION indicates that
each subdivision plant lot must contain at least one
deciduous street tree of two-inch caliper in residential
subdivisions, and each corner lot contains at least one
tree for each street upon which the lot fronts, located
so as not to interfere with sight distance at driveways
and chosen from the list of acceptable trees established
by the city manager.
TITLE 9. CHAPTER 9 SOLAR ACCESS establishes the
principles, applicability, and organization of solar energy
access. The section applies solar access codes to all city
property and all private property and developments.
Government organizations not under the jurisdiction of
the city may opt in unless provided an exemption by the
city manager. Three solar access zones are established
and organized into groups based on density, topography,
and lot orientations.
These are areas SA Area I, SA Area II, and SA Area III.
Each area has its own protections for solar entry based
on hypothetical shade height between two hours before
and two hours after local solar noon on a clear winter
solstice day. SA Area I is protected from shading 12 feet
high, SA Area II is protected from twenty-five feet high,
and SA Area III receives no protection.
TITLE 9.CHAPTER 2 SITE REVIEW establishes siting and
construction requirements to ensure maximum potential
for utilization of solar energy. In the city, applicants for
residential site reviews shall place streets, lots, open
spaces, and buildings so as to maximize the potential
for the use of solar energy in accordance with criteria,
including landscaping. The shading effects of proposed
landscaping on adjacent buildings must be minimized.
Boulder has a vision committed to establishing trees and
increasing solar energy generation. The code is flexible
to achieve harmony between solar panels and trees.
TITLE 6. CHAPTER 1 BIRD PROTECTION SANCTUARY
CREATED establishes that the area within the city is
declared to be a sanctuary for the refuge of protected
birds. Urban wildlife in Boulder is protected, including
birds, prairie dogs, bears, and bees. The city requires
permits for any injury or killing of protected urban
wildlife and works diligently with property owners to
identify non-lethal solutions to wildlife conflicts.
TITLE 8. CHAPTER 3 WILDLIFE PROTECTION states
that no person shall hunt, trap, net, impede, harass,
molest, chase, kill, or remove any wildlife or livestock
or damage, destroy, or remove any nest, burrow, or
animal dwelling from any park, recreation area, or open
space or other property of the city, including any ROW
controlled or maintained by the city.
Case Study: City of Atlanta Regulation
of Trees on Private Property
The City of Atlanta maintains clear regulations about
tree removal on private property. Atlanta’s tree
ordinance was developed by a core group of urban forest
stakeholders who began the process by considering
tree protection options in Georgia and nationwide.
The process for ordinance development provided for
public input, compromise and consensus. The strength
of the regulation lies in it being equitably enforced, and
having clear and unambiguous language. The ordinance
includes definitions, grants specific authority and
clearly describes penalties, and the appeals process.
To measure the effectiveness of the ordinance, key
metrics are tracked periodically.
These metrics include how many trees are preserved,
fees paid, number of violations, and levels of public
awareness. In Atlanta, these are measured annually
the Arborist Division. Fees paid for violations fund a
City Tree Trust which provides for future urban forest
enhancement.
Key Concepts:
• Convene a group of stakeholders to develop
regulations;
• Clearly establish applicability;
• Provide for public input, compromise, and
consensus; and
• Grant specific authority for enforcement to a
specific city agent.
WHAT DO WE HAVE?41
TITLE 6. CHAPTER 10 PESTICIDE USE (Boulder’s
Pesticide Ordinance) requires that Boulder residents
be notified when and where pesticides are applied.
It is the responsibility of the pesticide applicator to
notify all adjacent property owners at least 24 hours
prior to airborne application. Boulder's Integrated
Pest Management Policy extends that notification
requirement for city applications to include all pesticide
applications – airborne, ground, and trunk/soil injected.
Once notified, application must occur within seven days.
TITLE 5. CHAPTER 9. SECTION 7 UNREASONABLE
NOISE PROHIBITED BETWEEN THE HOURS OF 9 P.M.
AND 7 A.M.-- LAWN MOWERS, LEAF BLOWERS, AND
CONSTRUCTION allows exemptions for equipment used
to remove flood debris, which extends the operating
hours to 5:00am - 12:00am.
TITLE 8. CHAPTER 5 TEMPORARY TRAFFIC CONTROL
specifies that no person shall perform work (including
tree maintenance) in the ROW without providing
temporary traffic control measures. These requirements
are intended to enable safe passage for Boulder residents
on public ROW and are an important consideration for
any tree care personnel when developing work plans for
all tree care maintenance activities.
Urban Forest Strategic Plan Implications
Municipal ordinances impact the urban forest by
defining tree-related responsibilities for private
property owners, real estate developers, and tree care
companies. Specific requirements, such as the number
of trees required for a new development, can be altered
by Boulder leadership to increase the tree population
and expand the urban tree canopy.
WHAT DO WE HAVE?42
Design Standards
CHAPTER 3 OF BOULDER’S DESIGN AND CONSTRUCTION
STANDARDS: Streetscape Design and Tree Protection
is intended to improve public safety by preventing
sight distance and facility obstructions and sidewalk
and street damage, to promote suitable landscape
species selection for streetscapes, to minimize tree
and landscape maintenance costs, and to create an
aesthetic community image through continuity.
The standards identify requirements for the selection,
placement, and removal of trees on construction sites
and provide requirements for tree protection and
general landscaping and maintenance.
A key component to tree protection is the requirement
that applicants applying for construction projects where
streetscaping improvements will be included must
submit a landscaping plan in compliance with these
Standards and those set forth in TITLE 6 CHAPTER 6
(PROTECTION OF TREES AND PLANTS), TITLE 9 CHAPTER
2 (REVIEW PROCESS), AND CHAPTER TITLE 9 CHAPTER
5 (SUBDIVISIONS). This plan must include elements to
protect trees; design details and notes, construction
activity controls and measures, and any necessary
provisions or restrictions to ensure the protection of
existing trees.
While the standards state that trees shall only be removed
in compliance with a landscaping plan approved by the
city, this is not always the case. Currently, there is a
loophole for tree removal, where the owner/developer
simply removes trees prior to permitting.
Urban Forest Strategic Plan Implications
Design standards play a crucial role in the development
of an urban forest because they define the geographic
and spatial environment for trees. For example, soil
volume requirements impact the probability of a tree
developing into a healthy mature plant. City staff should
include arborists in the design process when standards
are updated to maximize the opportunity for trees to
succeed in urban environments.
Federal Wildlife Regulations
The Federal Migratory Bird Treaty Act protects all
common wild birds found in the United States except
for house sparrow, starling, feral pigeon, and resident
game birds, such as pheasant, grouse, quail, and wild
turkeys. The Migratory Bird Treaty Act makes it unlawful
for anyone to kill, capture, collect, possess, buy, sell,
trade, ship, import, or export any migratory bird,
including feathers, parts, nests, or eggs.
The Federal Endangered Species Act makes it illegal to
sell, harm, harass, possess or remove protected animals
from the wild.
Urban Forest Strategic Plan Implications
By practicing mindful tree maintenance practices,
disturbances or accidental injury to protected wildlife
and their habitats are minimized.
WHAT DO WE HAVE?43
$10.62
$13.99
$-
$2.00
$4.00
$6.00
$8.00
$10.00
$12.00
$14.00
$16.00
2003 2017Minimum City Staff Hourly Compensationwage was $10.62 per hour. Now, the minimum wage was
adjusted each year, where it reached $13.99 in 2017.
In February 2016, Resolution 926 expanded to other
categories of city employees, including part-time and
temporary. In 2017, the approved city budget included
increased funding for an expanding living wage for
city employees, janitorial and landscape contractors,
and emergency medical services (EMS) ambulance
providers. The 2017 Budget included funding to increase
wages rates for contracted janitorial and landscaping
Living Wage Regulations
Colorado state law currently prohibits local government
from establishing a citywide minimum wage. The statute
does not restrict local governments from establishing
policies that address the wages they pay to employees
or contractors. Without the option of establishing
a minimum wage across the board for all workers in
the community, City Council opted in 2003 to adopt
Resolution 926, which directed the city manager to pay
the city’s standard full-time employees no less than
120 percent of the Federal Poverty Guidelines (Chart
3). In 2003, when the Resolution was implemented, the
service providers, as well as for EMS ambulance service
providers, to a minimum rate of $15.67 per hour.
Urban Forest Strategic Plan Implications
All Forestry contracted services (planting, pruning,
removals, and pesticide applications) are included
within the definition of landscaping service provider.
It is still unknown whether the new living wage will
significantly impact Boulder Forestry contracted tree
care operations.
Chart 3: Municipal Compensation Requirements
WHAT DO WE HAVE?44
Private
91.5%
Public
8.5%
Understanding the structure, composition, and condition
of an urban forest resource is essential to developing
effective management strategies.
The following information provides an overview of
Boulder’s urban forest and the public tree resource,
including important benchmarks for measuring the
success of the UFSP over time. The public tree resource
is comprised of all public trees, while the urban forest
contains all public and private trees (Chart 4). Boulder's
urban forest has approximately 50,800 public trees and
600,000 private trees.
Boulder’s Urban Forest
Resource
Chart 4: Public vs Private Trees
"We often notice trees as stationary plants that only move with the help
of wind, rain or other natural elements. That helps us know they are alive.
Another option is viewing the energy that trees emit. During the early or
late hours of the day, relax your eyes as if you were caught up in a carefree
daydream; focusing on nothing, but still capable of observing. View the
edges of the tree and at times you can see shades of transparent silver
against the sky background. Every living thing emits energy. Trees give us
innumerable opportunities to be aware and connected."
~Submission to Boulder Tree Stories
WHAT DO WE HAVE?45
Canopy
16%
Impervious
33%
Pervious
47%
Water
4%
Urban Tree Canopy
The amount and distribution of leaf surface area are the
driving forces behind the ability of the urban forest to
produce benefits for the community (Clark et al, 1997).
As canopy cover increases, so do the environmental
services and socio-economic benefits.
Tree canopy is the layer of leaves, branches, and stems
of trees and other woody plants that cover the ground
when viewed from above. Understanding the location
and extent of tree canopy is critical to developing and
implementing sound management strategies that will
promote the smart growth and resiliency of Boulder’s
urban forest and the invaluable services it provides.
In 2015, through a partnership with Trimble and Digital
Globe, Boulder used remote sensing and high-resolution
aerial imagery (NAIP, 2013) to develop an initial GIS land
cover data layer that identifies tree canopy, impervious
surface, pervious surface, and water. In 2016, Davey
Resource Group completed mapping in some areas not
covered in the initial study and provided an accuracy
assessment and quality assurance for the overall dataset.
The result is a GIS map layer detailing the location
and extent of existing tree canopy and other land
cover across Boulder. The analysis does not distinguish
between trees on public and private property since the
benefits of trees extend beyond property lines. The
information can be used by urban forest managers to
explore tree canopy in conjunction with other available
metrics, including geography, land use, and community
demographics. This information also establishes a
baseline for assessing future change.
Land Cover
Boulder encompasses 17,473 acres. Tree canopy covers
approximately 2,773 acres for an average canopy cover
of 16 percent (Chart 1, Table 1). Impervious surfaces
such as pavement (roads, sidewalks, driveways and
parking lots) and developed area, cover 5,724 acres
(33%). The most prevalent land cover is pervious
surfaces like turf, low-lying vegetation, and bare soils,
covering 8,198 acres (47%) (Map 1). Although all grass,
low-lying vegetation, and bare soil cover types are
potential planting locations, realistically, not all areas
are suitable planting sites due to intended site uses.
Examples of sites with limited canopy potential include
Golf courses, cemeteries, and sports fields. With these
considerations in mind, Boulder has a potential canopy
cover of 41 percent.
Tree Canopy by Maintenance District
Land cover was further stratified across 14 tree
maintenance districts (Map 3). Boulder’s land cover
by maintenance district varies, from 30 percent in
University Hill to 3 percent in Gunbarrel. Boulder’s
parks and trail areas include 122 acres of tree canopy,
an average of 7.7 percent. Parts of Boulder Creek Path
have 70 percent tree canopy cover while natural areas
near Boulder Reservoir, Bill Bower Park, and North Palo
Park have less than 2 percent.
Chart 1: Land Cover
Table 1: Land Cover Classes
Land Cover Class Acres Percent
Canopy 2,773 16%
Impervious 5,724 33%
Pervious 8,198 47%
Water 755 4%
Total 17,453 100%
Land Cover Class Acres Percent
Canopy 2,773 16%
Impervious 5,724 33%
Pervious 8,198 47%
Water 755 4%
Total 17,450 100%
WHAT DO WE HAVE?46Map 1: Land Cover Map 3: Canopy Cover by Maintenance District
WHAT DO WE HAVE?47
Annual Services
Air Quality Pounds Value ($)
O3 183,760 $12,861
PM10 61,560 $9,337
NO2 18,460 $247
CO 3,380 $143
SO2 11,620 $43
Carbon Tons
Sequestration 18,709 $676,508
Stormwater Gallons
Avoided Runoff 15,001,357 $177,016
Annual Total $876,155
Carbon Tons Value ($)
Storage 471,714 $17,056,868
Lifetime Carbon Storage
Environmental Services
i-Tree Canopy (v6.1) was used to calculate the
environmental services provided by the entire Boulder
tree canopy. This includes annual services to air
quality, human health, stormwater runoff, and carbon
sequestration. It does not include other tree services
such as energy savings or increased property values.
Each year, Boulder’s urban forest provides a total of
$876,155 in environmental services. The majority of
this value comes from reduced greenhouse gases;
annually trees sequester 18,709 tons of carbon valued
at $676,508. The i-Tree Canopy v6.1 model was used
to quantify the value of ecosystem services for carbon
storage and sequestration.
The i-Tree Canopy v6.1 model was also used to estimate
air pollutant removal rates and monetary values for
carbon monoxide (CO), nitrogen dioxide (NO2), ozone
(O3), sulfur dioxide (SO2), and particulate matter (PM)
(Hirabayashi, 2014). Annually, trees in Boulder trap or
absorb 139 tons of air pollutants valued at $22,631.
Improvements to air quality are also linked to human
health services.
The i-Tree Hydro v5.0 model was used to quantify the
value of ecosystem services for stormwater runoff.
Through model simulation, it was determined that tree
canopy reduces stormwater runoff volume in Boulder by
more than 15 million gallons per year using precipitation
data from 2005-2012. This is approximately 5,408
gallons per acre of tree canopy. Based on an estimated
stormwater treatment cost of $0.0118 per gallon, tree
canopy contributes $177,016 annually to stormwater
services.
Forest Fragmentation
Forest fragmentation is the result of roads and other
urban development creating separations, holes, or
pockets that reduce large contiguous forested areas
into smaller stands. Fragmentation results in tree
canopies that are isolated from each other, reducing
habitat value and isolating wildlife populations.
Mapping fragmentation can help identify areas where
tree planting and new canopy can increase linkages and
habitat corridors. The fragmentation study identified
2,289 acres of patch canopy (small isolated patches),
370 acres of perforated canopy (edges and linear
sections), and 110 acres of core canopy (Map 4, Figure
3). Fragmentation was a consideration of the priority
planting analysis for Boulder.
The effects of fragmentation are well documented in
all forested regions on earth. In general, by reducing
forest health and degrading habitat, fragmentation
leads to loss of biodiversity, increases in invasive plants,
pests, and pathogens, and reduces water quality. These
wide-ranging effects all stem from two basic problems:
(1) fragmentation increases isolation between forest
communities and (2) it increases so-called edge effects
(Bennett, 2003).
When a forest becomes isolated, the movement of
plants and animals is inhibited. This restricts breeding
and genetic diversity, which results in long-term
population decline. Fragmentation is a threat to natural
resilience, and connectivity of forest habitats may be
a key component of forest adaptation and response to
climate change.
Table 4: Ecosystem Services From Tree Canopy
Cumulative Stored Carbon
As trees grow, they remove atmospheric carbon to fuel
the growth of woody and foliar biomass. Over their
entire life to date (lifetime value), the trees in Boulder’s
urban forest are storing 471,714 tons of carbon, valued
at over $17 million (Table 4). In the coming years, as
trees are lost to EAB, carbon storage may fluctuate or
decrease, depending upon the final disposal or reuse of
woody biomass.
WHAT DO WE HAVE?48
Fragmentation Class Acres Percent
Patch 2,289 83%
Perforated 371 13%
Core 111 4%
Total 2,770 100%
Map 4: Forest Fragmentation
Figure 3: Forest Fragmentation Detail
Table 5: Forest Fragmentation
WHAT DO WE HAVE?49
31%30%
22%
17%16%16%16%
11%10%9%8%
0%
5%
10%
15%
20%
25%
30%
35%Tree Canopy CoverHow does Boulder’s tree canopy measure up?
To provide a better regional context for Boulder's urban
forest tree canopy, the UFSP provides the Urban Tree
Canopy for several comparison communities (Chart
5). Boulder has a 16 percent canopy cover which is
approximately equal to Denver and Boise.
It is important to note that different communities may
have different canopy cover percents for many reasons,
including land use patterns, climate, soil conditions,
natural precipitation, and budgets. Every city needs to
develop canopy goals that are appropriate for their own
community.
Planting Priorities
It could be assumed that all pervious areas, including
grass, shrubs, low vegetation, and bare soil (8,198 acres)
are potential tree planting locations. Realistically, not
all of these areas are suitable planting sites due to
intended site uses (e.g., golf courses, cemeteries, sports
fields) and because some of these areas are natural
areas (without irrigation) that are not appropriate for
tree planting.
Potential realistic plantable areas can be determined by
excluding those pervious areas unsuitable for planting
and including impervious areas where trees could
feasibly be added, such as in parking lot islands, along
sidewalks, and near road edges.
The Urban Tree Canopy analysis considered site design
and environmental factors, including proximity to
hardscape, canopy fragmentation, soil permeability,
slope, and soil erosion factors to prioritize planting sites
on both public and private property for the greatest
potential return on investment (Map 5, Figure 4). As
young trees mature, they provide more substantial
stormwater and environmental services. The analysis
identified 4,335 acres of potential planting site in
Boulder, where 905 of these acres are high or very high
priority planting areas. It is important to note that some
of the areas in the planting priority map are not under
the jurisdiction of the City of Boulder (Table 6).
Management Applications
Understanding the location and extent of tree canopy is
key to developing and implementing sound management
strategies that promote the sustainability of Boulder’s
urban forest resource and the services it provides
(Figure 4). The data set, combined with existing and
emerging urban forestry research, enables managers
to strike a balance between urban growth and tree
preservation and aids in identifying and assessing urban
forestry opportunities. Spatial understanding of the
past, present, and future potential for tree canopy is
a valuable tool to help managers align urban forestry
management with the community’s vision for Boulder’s
urban forest.
Chart 5: Comparison Community Canopy Cover
WHAT DO WE HAVE?50Map 5: Priority Planting Sites
Priority Ranking Number of Locations Acres Percent
Very Low 14,682 1,393 32%
Low 16,906 1,141 26%
Moderate 16,484 889 21%
High 18,449 590 14%
Very High 13,881 314 7%
Total 80,402 4,327 100%
Table 6: Priority Planting Sites
Figure 4: Priority Planting Detail
WHAT DO WE HAVE?51
Species Total % of Total
Green ash $12,979,158 11.8%
Siberian elm $11,505,266 10.5%
Honeylocust $9,143,368 8.3%
Silver maple $8,927,310 8.1%
Cottonwood $6,539,223 5.9%
All Other Trees $60,860,845 55.4%
Total $109,955,170 100%
Species % of Street Trees
Siberian elm 11.3
Green ash 10.9
Honeylocust 8.4
Crabapple 6.1
Silver maple 4.3
Blue spruce 3.5
Austrian pine 2.7
Northern hackberry 2.4
Norway maple 2.4
American basswood 2.3
Russian olive 2.1
Pinyon pine 2.0
Swamp white oak 1.9
Callery pear 1.9
White ash 1.8
Quaking aspen 1.7
Littleleaf linden 1.6
Western catalpa 1.6
Juniper 1.5
Boxelder 1.4
Cottonwood 1.4
Ponderosa pine 1.3
Sugar maple 1.3
Cherry 1.2
Red maple 1.2
Northern red oak 1.2
Bur oak 1.0
All Other Street Trees 19.6
Total 100%
Species % Of Park Trees
Green ash 9.1
Cottonwood 8.1
Austrian pine 6.2
Plains cottonwood 5.2
Blue spruce 4.6
Ponderosa pine 4.4
Crabapple 3.8
Honeylocust 3.8
Siberian elm 3.7
Willow 3.3
Pinyon pine 2.2
Crack willow 2.1
Northern hackberry 2.1
Boxelder 2.0
Rocky mountain juniper 1.9
Western catalpa 1.8
Bur oak 1.6
American basswood 1.6
Swamp white oak 1.3
Kentucky coffeetree 1.3
White fir 1.2
English oak 1.0
All Other Park Trees 27.7
Total 100%
Species % of Public Trees
Green ash 10.4
Siberian elm 9.3
Honeylocust 7.2
Crabapple 5.5
Blue spruce 3.8
Austrian pine 3.6
Silver maple 3.4
Cottonwood 3.1
Northern hackberry 2.3
Ponderosa pine 2.1
American linden 2.1
Pinyon pine 2.1
Norway maple 2.0
Swamp white oak 1.7
Russian olive 1.7
Plains cottonwood 1.6
Western catalpa 1.6
Callery pear 1.6
Boxelder 1.5
White ash 1.5
Littleleaf linden 1.4
Juniper 1.3
Quaking aspen 1.3
Willow 1.2
Bur oak 1.2
Northern red oak 1.1
Rocky mountain juniper 1.0
Sugar maple 1.0
All Other Trees 22.4
Total 100%
Public Tree Resource
In 2015, certified arborists collected an inventory of
the public trees in Boulder, including details about
each tree’s species, size, and condition. The inventory
recorded the species, size, condition, and geographic
location of each tree in an electronic, GIS format.
The tree inventory data was analyzed with i-Tree’s
Streets, a STRATUM Analysis Tool (Streets v5.1.5; i-Tree
v6.0.9), to develop a resource analysis and report of
the existing condition of this urban forest.
Boulder’s public tree resource includes approximately
50,800 inventoried street and park trees. To replace
these trees with trees of similar size, species, and
condition would cost nearly $110 million. (Table 7).
Species Diversity
The public tree inventory includes more than 235
unique tree species. This greatly exceeds the mean of
53 species reported by McPherson and Rowntree (1989)
in their nationwide survey of street tree populations in
22 U.S. cities. This level of diversity is not typical of a
temperate, semi-arid climate. One contributing factor
Table 7: Replacement Value of Top 5 Species
Street Trees Park Trees All Public Trees
WHAT DO WE HAVE?52
0%
5%
10%
15%
20%
25%
30%
35%
40%% of All TreesDBH Class
Ideal
All Trees
is the acidity of Boulder’s soils, which makes them
more productive than soils in other Front Range cities,
allowing a wider diversity of species to be planted. The
most predominant tree species are green ash, Siberian
elm, honeylocust, crabapple, and blue spruce.
The prevalence of green ash exceeds the general rule
that no single species should represent more than 10
percent of the population (Clark et al. 1997). In light
of EAB and other significant pests and diseases, many
cities are now opting to increase diversity to improve
resilience. The 10-20-30 is a widely used standard for
urban forestry, which states that urban tree populations
should consist of no more than 10 percent of any one
species, 20 percent of any one genus, and 30 percent
of any one family. The rule encourages greater genetic
diversity, and thus, greater resilience. Only 25 of the
more than 235 species in Boulder's public tree population
represent more than 1 percent of the overall population.
Boulder is experimenting with a lot of tree species to
increase diversity and overall forest resiliency.
Additionally, at the neighborhood level, some areas are
heavily dominated by only a few species. In Northeast
Boulder, nearly three in ten trees are green ash. In
Mapleton Hill, one-quarter of the trees are silver
maples and in Northeast Broadway, one-quarter are
Siberian elms. One in five trees among Boulder’s parks
are cottonwoods.
The lack of species diversity at this level is of concern
due to the impact that drought, disease, pests, or other
stressors can have on an ecosystem; the urban forest
is no different in this respect. Green ash, for example,
is already particularly vulnerable to EAB. Silver maples
may be at risk as well. While not yet detected in
Colorado, the Asian long-horned beetle (Anoplophora
glabripennis) feeds on maples and other species,
including poplars, elms, and willows. A catastrophic loss
of one or more of these dominant species would leave
large structural gaps in Boulder’s neighborhoods.
Future planting should focus on increasing diversity and
reducing reliance on overused species. As at-risk tree
species are removed and replaced, new species should
be introduced when possible. New species should be
resistant to the pest issues that currently pose a threat
to the region. For example, it would not be beneficial
to replace the green ash trees in Northeast Boulder with
autumn purple ash, because they would still be at risk
from EAB. Ideally, replacement of at-risk species should
include a diversity of tree species.
Age Distribution
The age distribution of the urban forest is a key indicator
and driver, of maintenance needs. The age distribution
of Boulder’s public tree population is mainly small-
diameter trees, with over two-thirds of the trees under
12" Diameter at Breast Height (DBH). Almost 30 percent
of the trees are between 6"-12" (Chart 6).
13,034 of young trees (<6” DBH) are medium and large-
stature trees that still have a lot of growing to do before
they reach maturity. Training, defined as the selective
pruning of small branches to influence the future shape
and structure of a young tree, is critical at this stage
to prevent costly structural issues and branch failures
as these young trees mature into their final size in the
landscape.
14,911 of the population consists of intermediate age
Chart 6: Age Distribution of Public Trees
trees with a DBH between seven and twelve inches.
Of these, 11,817 are medium and large-maturing trees
that will also benefit from pruning to influence their
developing structure. 11,817 of the overall population
is comprised of small-maturing trees that generally
don't exceed 25 to 30 feet in height.
A high proportion of young, large, and medium-maturing
trees is a positive indication for the benefits provided by
the urban forest, since large shade trees typically provide
more shade, pollutant uptake, carbon sequestration, and
rainfall interception than small trees. 3,661 of the tree
inventory is comprised of mature and over-mature trees
with a DBH exceeding 24 inches. When trees approach
or reach the end of their natural lifespan, they often
have higher maintenance needs and eventually need to
be removed to reduce risk and liability.
WHAT DO WE HAVE?53
$46.28
$5.45
$6.98
$15.19
$17.27
$28.14
$28.80
$40.45
$43.58
$66.36
$66.96
$67.33
$72.87
$79.78
$84.39
$93.97
$103.46
$121.72
$126.74
$131.65
$143.37
$145.88
$150.44
$158.43
$160.71
$195.64
$282.52
$291.14
$360.87
$0.00 $50.00 $100.00 $150.00 $200.00 $250.00 $300.00 $350.00 $400.00
All Other Trees
Rocky mountain juniper
Pinyon pine
Callery pear
European crabapple
Quaking aspen
Juniper
Willow
Swamp white oak
Northern hackberry
American linden
Bur oak
Austrian pine
Western catalpa
Blue spruce
Honeylocust
Green ash
Russian olive
Littleleaf linden
Siberian elm
Boxelder
Ponderosa pine
White ash
Sugar maple
Norway maple
Northern red oak
Plains cottonwood
Cottonwood
Silver maple
Summary of Total Annual Per-Tree Services
Energy Stormwater CO₂Air Quality Aesthetic/Other
Services Provided by the Urban Forest
Boulder’s public trees provide an estimated 651 acres
of tree canopy, approximately 23.5 percent of the
overall tree canopy cover. To date, public trees have
sequestered 36,892 tons of carbon dioxide (CO2), valued
at $243,490.
Annually, Boulder’s public trees provide cumulative
services to the public at an average benefit of $102 per
tree, for a total value of nearly $5.2 million each year
(Chart 7). These annual services include:
• $442,432 in energy use reduction (electricity and
natural gas) through shading and climate effects;
an average of $8.72 per tree;
• 2,254 tons of CO2 sequestered for an overall
value of $43,084; an average of $0.85 per tree.
• $66,282 in air quality improvements; an average
of $1.31 per tree;
• 30.6 million gallons of stormwater intercepted
for a total value of $153,038; an average of $3.02
per tree; and
• $4.5 million in increased property values and
other socio-economic benefits; an average of
$88.59 per tree.
It is important to note that three of these top fifteen
performing tree species are vulnerable to either the EAB
(white ash and green ash) or drippy blight (red oak).
Chart 7: Annual Services From Prevalent Public Tree Species
WHAT DO WE HAVE?54
Dead or
Dying
1%
Poor
7%
Fair
29%
Good
56%
N/A
6%Very
Poor
1%
Condition
The majority of trees (91%) in Boulder’s public urban
forest are in fair or better condition. Less than 7 percent
of trees are in poor condition and 1.9 percent are dead
or in very poor condition (Chart 9).
While there are some older, mature trees that require
structural maintenance or removal, Boulder is fortunate
to have a relatively young and healthy public tree
population. Proactive management, especially timely
training and structural pruning, remains critical to
maintain the condition of this valuable forest resource.
Return on Investment
When the annual investment of nearly $1.17 million for
the management of the public urban forest is considered,
the annual net benefit (services minus investment) for
the community is over $4 million, an average of $39 per
tree (Chart 8). In other words, for every $1 invested
in public trees, the community receives $4.46 in
services. Boulder’s benefit-investment ratio of $4.46
exceeds those reported in 2005 for Bismarck, ND ($3 .09),
Glendale, AZ ($2.41), Fort Collins ($2.18), Cheyenne,
WY ($2.09), and Berkeley, CA ($1.37) (McPherson et al.
2005).
Trees in Open Space and
Mountain Parks
The urban forest as discussed in this Plan does not include
trees in open spaces and mountain parks. Boulder's Open
Space and Mountain Parks (OSMP) include over 45,000
acres of land that have been preserved and protected.
Wildlife habitat, unique geologic features, greenways,
and 151 miles of trails are all part of OSMP. The open
space lands teem with native plants and wildlife and
are home to threatened and endangered species.
In addition, these lands serve as a buffer between
Boulder and nearby development, and contain a tree
population that also provides environmental services. A
full explanation of how OSMP trees are managed can be
found in the OSMPs Forest Ecosystem Management Plan.
Chart 9: Overall Condition of Public Trees
Chart 8: Return on Investment for Public Trees
WHAT DO WE HAVE?55
"Boulder Forestry is committed to maintaining a
healthy and safe urban forest and to preserving
an extensive and diverse tree resource for future
generations."
Boulder Forestry staff and programs are nationally
recognized within the industry for their expertise and
proactive approach to urban forest management. The
Boulder Forestry Division currently has seven full-time
positions, including: the city forester, a forestry field
operations supervisor, three assistant foresters, and
two forestry field technicians.
Two to three seasonal staff positions are available to
provide support on an as-needed basis. Forestry staff
has many years of experience managing Boulder's public
trees. The forestry staff also includes International
Society of Arboriculture certified arborists and Certified
Tree Risk Assessors. These certified professionals
participate in training and industry events to keep
their skillset and knowledge informed by contemporary
industry BMPs.
All individuals from tree care companies performing
work to public trees must be city licensed certified
arborists and adhere to all applicable industry standards,
including ANSI, A300, and Z133. ISA certified arborist
contractors follow industry standards, including ANSI,
A300, and Z133, and maintain a license to perform tree
care to public trees.
Rotational and Safety Pruning
Pruning serves to maintain the health, safety, structure,
and aesthetic value of individual trees and is needed on
a periodic basis as trees grow and increase in diameter
and canopy. Maintenance pruning for public trees falls
into two main categories: rotational (routine) pruning
and safety (risk management), although risk reduction is
also a goal of routine pruning. In instances where trees
are near busy streets, playgrounds, multi-use paths, and
pedestrian areas, pruning can significantly reduce the
risk of tree failure. Pruning is also required to ensure
visibility in the “sight triangle” at street intersections
as well as for traffic signals and signs.
Tree longevity and stability are enhanced with structural
pruning from a young age. Structural pruning can also
reduce the cost of maintenance over time by reducing
the number and size of branches that require removal
on mature trees and the amount and size of tree debris.
Industry best practices recommend rotational pruning
every five to seven years for all public park and street
ROW trees.
Until 2012, public street trees greater than ten inches
in diameter received maintenance pruning on a ten-
year cycle and park trees on an eight-year cycle. In
recent years, due to budget constraints, reallocations
to manage EAB and storm damage, and increased
contractor pricing, the pruning rotation has fallen
behind schedule. The current rotation is closer to 14-15
years for street trees > 10” diameter and nine to ten
years for all park trees.
Safety pruning outside the rotation is performed on
an as-needed basis. Trees are identified for safety
Boulder is an industry leader in urban forestry and
several programs have been nationally recognized for
excellence. The following programs illustrate Boulder’s
commitment to high-quality tree management.
Core Programs:
• Rotational and safety pruning;
• Tree safety inspection program (TSIP);
• Tree removal;
• Tree planting and replacement;
• Integrated pest management:
• Protecting pollinators
• Emerald Ash Borer (EAB) mitigation
• EAB control methods in Boulder;
• Commercial tree program;
• Tree inventory and asset management;
• Development review, tree protection, and
mitigation;
• Enforcement of tree regulations;
• Arborist licensing and staff training;
• Emergency storm response;
• Communication, public outreach and notification;
• Public service requests; and
• Wood utilization.
Boulder's Forestry is committed to maintaining a healthy
and safe urban forest and to preserving an extensive
and diverse tree resource for future generations.
City Forestry Programs
and Operations
WHAT DO WE HAVE?56
mitigation through routine inspections and maintenance,
risk assessment surveys for the Tree Safety Inspection
Program, and resident service requests. Urgent hazards
are addressed as quickly as possible.
Case Study: Pennsylvania Horticultural
Society Tree Tenders
PHS Tree Tenders, established in 1993, is one of the
oldest, most respected volunteer urban tree planting
and stewardship programs in the nation. Tree Tenders
was developed as a decentralized program to “train
the trainers” about trees, community organizing,
communicating with elected officials, working with
the media, and neighborhood involvement. The
program offers hands-on tree care training, covering
biology, identification, planting and proper care. Since
inception, the training program has graduated more
than 4,000 Tree Tenders in the Greater Philadelphia
area. Working in neighborhood groups, the program’s
volunteers are responsible for planting more than
2,000 trees annually.
Tree Tenders basic training is a one-day or three-evening
comprehensive introduction to tree care concepts,
offered for a $25 fee with scholarships available
based on economic need. The program initially was
free, but there were a large number of no-shows, and
the participant investment of $25 greatly improved
attendance. The scholarship is a way to make sure no
one is turned away due to economic circumstance.
Advanced tree tender trainings are available as online
webinars which feature a webinar from a nationally
recognized tree expert and a quiz. These help provide
detail and depth to compliment the tree tenders
basic program as well as connect tree tenders with
other organizations that can support their projects.
Participants who complete all eight 1.5-2 hour webinars
receive an Advanced Tree Tenders Certificate.
The program is interconnected to multiple PHS
programs, so it is not possible to determine exact
program costs. The funding comes from the nonprofit’s
annual flower show, a state Department of Conservation
and natural resources grant, individual donors, and
members.
Some of the speakers, including professors from
the local university, volunteer their time, reducing
potential program costs.
Key Concepts:
• Provide opportunities for volunteers to take on
leadership roles;
• Build a team of engaged advocates that
understand the community’s unique urban
forestry challenges and opportunities;
• Scholarships are available; and
• Advanced classes are provided by webinar.
When funding is available, it is generally dedicated
to resolve issues in the largest, most mature trees,
while younger trees that would benefit greatly from
structural pruning and correction become neglected.
This deferred maintenance will eventually result in
higher, long-term costs that will negatively affect
the health and longevity of the overall urban forest,
as well as increase future risk of partial or full tree
failure.
Adjacent property owners may contract the pruning of
public street ROW trees outside of the pruning cycle
(B.R.C. 6-6-5 Spraying and Pruning). Property owners
must receive prior authorization from Boulder Forestry
and hire a City of Boulder licensed certified arborist.
WHAT DO WE HAVE?57
data is collected in the field and stored in a database.
Over time, as high-risk trees have been removed,
the overall risk in the public tree resource has been
reduced. The scope of the TSIP, however, represents a
Tree Safety Inspection Program
The Tree Safety Inspection Program (TSIP) is an
ongoing inspection and monitoring program for public
trees with known structural defects. TSIP aids in the
prioritization of maintenance activities to reduce risk,
including mitigation pruning and tree removal. Surveys
are conducted for public trees on streets, in parks, and
along Boulder Creek Path and other greenways. Each
tree is inspected once every three to seven years and
surveys should be repeated on a maximum seven-year
cycle. When a tree’s condition exceeds the threshold of
safety, the tree is then pruned to mitigate the hazard
or removed if risk mitigation is not appropriate. Trees
in naturalized areas are only assessed if they have the
potential to impact public paths.
A significant focus for TSIP is Boulder's large population
of aging silver maples. Many of these trees were planted
in the late 1800s and are now over 100 years old. Silver
maples are poor at compartmentalizing decay and are
weak wooded and prone to limb failure. They represent
52 percent of the trees in TSIP and their future
maintenance will strain pruning and removal budgets
already taxed by tree removals due to EAB and severe
weather events.
TSIP exceeds national standards for tree risk
management. As a result, reported claims due to tree
failures have been kept to a minimum. Prior to 2006,
staff inspected approximately 150 trees per year. Since
2006, that number has increased to an average of 225
trees per year due to the advancing age and size of
trees in older neighborhoods. Historical trends suggest
the number of removals is expected to increase. All
significant logistical and resource burden on Boulder
Forestry operations. The UFSP recommends a review
of the program along with an overall risk management
policy.
Cavity and decay in public silver maple tree.
WHAT DO WE HAVE?58
Tree Removal
Boulder Forestry is responsible for the removal of public
trees that are dead, dying, structurally unsound, or
threatening to people or property. Trees that pose a
danger of spreading insect or disease pathogens may
also be removed to protect the overall urban forest.
Trees that are ten inches in diameter or smaller are
typically removed by forestry staff, while large tree
removals are contracted through local arborists.
Recently, several large contracts have been awarded to
out-of-state arborists due to the increasingly prohibitive
costs of local arborists. Sourcing only to local companies
requires a deliberate call to action from Boulder voters,
including a commitment to additional funds.
Prior to 2013, Boulder Forestry removed an average
of 250 trees per year (Chart 10). Since 2013, removals
have increased significantly to over 900 trees in 2016
and 1,300 trees in 2017. Boulder Forestry estimates
that these numbers will continue to increase even
further as a result of EAB, severe weather events (e.g.,
the 2014 freeze and 2016 spring snowstorms), and the
continued decline of historic silver maples in Mapleton
Hill, University Hill, and Whittier maintenance districts.
Trees are also removed by other city work groups or
private entities because of city construction projects,
flood mitigation projects or private development.
Despite an increase in removals, tree removal decisions
(whether within the city or private) development
process are not taken lightly and trees are preserved
whenever possible. For private development projects,
tree removal decisions are made based on specific
criteria, which can involve the Planning Board or City
Council. The project must satisfy and balance criteria
for removal and is agreed on by Forestry staff prior to
advancing to Planning Board.
Forestry staff serves in an advisory role and as an
information resource for determinations on tree removal
in development and city construction projects. The
decision to remove a public tree through development
is ultimately made by the project manager, advisory
board, or City Council. Thus, Forestry does not make
removal decisions for projects in other departments.
When a private resident wants to remove a public tree,
the Forestry and the Planning Department work together
to explore alternatives to removal and to determine if
the tree is worthy of preservation.
Chart 10: History of Tree Planting & Removal - Boulder Forestry
WHAT DO WE HAVE?59
Tree Planting and Replacement
To maintain the public tree resource and urban tree
canopy cover along with the environmental, social,
and economic services that the urban forest provides,
Boulder Forestry replaces public trees that have been
removed and plants additional trees where existing
space and infrastructure allow. Tree planting activities
are divided between an in-house crew and outside
contractors. The amount contracted varies from year
to year based on how busy the in-house staff members
are with other tree activities, such as storm damage
response or service requests. In-house planting is less
expensive, so the city could plant more trees annually
if in-house was used exclusively for plantings. Trees in
commercial locations and for special planting initiatives,
such as ash replacement, are generally planted by
outside contractors.
To help offset the loss of environmental services caused
by the removal of a mature tree, industry standards
recommend replacing trees at a minimum of two new
trees for every one tree removed (2:1). However, due
the high number of recent tree removals along with
budget shortfalls, Boulder Forestry has struggled to
maintain a 1:1. The 2017 budget allocated $18,500 to
planting. To reach the 2:1 goal, future budgets should
receive substantial increases.
Historically, Boulder Forestry’s Tree Planting Program has
planted between 200 to 600 trees each year, depending
on funding. Hundreds more are added to the landscape
through city projects and private development activities.
Maintaining tree diversity is the key to resilience in the
face of invasive tree pests and climate change. Boulder
Living Legacy Program
The Living Legacy Program provides individuals and
organizations with the opportunity to honor and
commemorate the memory of individuals and special
events by planting a tree in Boulder’s city parks. While
prices vary due to species, size, and time of purchase,
the average cost per tree is approximately $275.
Forestry staff strives to plant a minimum of 35 different
tree species annually. To maximize tree services, 90
percent of new trees planted by Boulder Forestry are
large-maturing species.
Tree establishment requires regular irrigation and
special attention to soil quality. Sites with a functional
irrigation system receive priority status for replacement
trees. Due to existing limitations, Boulder Forestry
cannot replace all trees. This is especially true for
trees along arterials or adjacent to rental properties,
due to lack of irrigation or lack of functional irrigation
systems. Irrigation was required at planting but often
not maintained for site review projects.
Soils in West Boulder are generally fair to good with
acidic pH and higher organic matter content. Some
areas in East Boulder and Gunbarrel have low soil organic
content, low soil fertility, poor drainage, as well as
variable soil type and pH. Boulder Forestry collaborates
closely with city Planning and Transportation staff to
ensure species selection accounts for multiple site and
soil variables for city and private development projects.
Currently, the Tree Planting Program has a Request to
Proceed memo signed by the city manager, which allows
Boulder Forestry to purchase trees outside of normal
purchasing requirements. This strengthens the program
considerably since it is vital to select only high quality,
neonic-free, diverse tree species. Low-cost is not always
the highest priority when selecting quality tree stock.
WHAT DO WE HAVE?60
Case Study: ReGreen Tulsa
ReGreen Tulsa was a successful public-private
partnership to plant 10,000 trees, a prime example
of urban forest resiliency in action. A December 2007
ice storm caused unprecedented damage to Tulsa’s
urban forest. Over 20,000 trees were lost throughout
the community, including 7,000 trees in city parks.
In response, Tulsa’s mayor at the time, Kathy Taylor
worked with Up with Trees and leveraged city resources
to kick off the project in 2008. Ultimately, through
individual and corporate donations the community
dedicated $1.5 million in private funding which was
matched by the Tulsa Community Foundation to fund
the $3 million nine-year project.
A diverse species palette, focusing on storm-resilient
trees was selected. Trees were planted at schools,
parks, city properties, and in 16 neighborhoods. The
project had 15 collaborative partners to plant trees
at 196 locations throughout Tulsa. Volunteer crews
were trained to help plant the trees, recruiting many
residents from nearby neighborhoods. It is estimated
that around 5,000 volunteers participated in tree
planting events. Up with Trees recruits one volunteer
for every 2 trees planted, at events that are typically
held 9-11am on weekend mornings. ReGreen plantings
became the catalyst for the development of the Citizen
Forester program to develop volunteer leadership.
Over the course of the ReGreen program, managers
identified several strategies and elements that
contributed to program success. First, ReGreen Tulsa
had a sense of urgency due to the massive citywide
storm damage and this sparked strong political and
community support for a tree planting initiative. The
program vision and funding came together relatively
quickly (in about 2 months) based on existing
partnerships with the Tulsa Community Foundation,
City of Tulsa and Up With Trees. Because the program
was based on a foundation grant and nonprofit
donations, the funding was relatively stable, rather
than subject to city budget fluctuations.
When planting thousands of trees, even small price
reductions in per-tree cost can really add up - in this
case, to an estimated $250,000. ReGreen trees had
a cost of $300 for planting, watering and warranty.
Today, UWT estimates that cost at $400 per tree due
to inflation and stock availability. Ultimately, one
of the main program successes was a shift in public
perception - through education, advocacy, and
dialogue with volunteers and community leaders - that
changed from trees being perceived as an aesthetically
beautiful amenity to a valuable infrastructure asset.
Program organizers acknowledge several lessons
learned from this program’s implementation. They
recommend collaborating with partners (school
district, fire department, etc.) earlier, and more
carefully considering the locations of trees to increase
canopy in areas of highest need. It was challenging
to find planting locations in low income, low canopy
areas because of the higher prevalence of renters, who
lacked the ability to provide maintenance, or simply
lacked the time to care for a newly planted tree. To
overcome this challenge, UWT plans to work closely
with the Working in Neighborhoods Department of the
City of Tulsa, and spend more time canvassing and
cultivating community support. The tree mortality rate
ranged from 3 percent in years of regular precipitation
to 9 percent in drought years, which was still below
the industry average of 10 percent. By spreading tree
planting over 9 years, the risk of catastrophic loss - in
the event of severe drought - was mitigated. Perfecting
summer irrigation timing and methods was seen as a
key to successful tree establishment.
Key Concepts:
• Establish a tree planting goal and a timeframe.
Allow the first year to be a planning phase;
• Collaborate with partners early and often;
• Create a call to action and clearly articulate
“Why now?”;
• Focus tree planting where community need is
greatest;
• Work strategically to source high-quality,
diverse, low cost nursery stock;
• Diversify funding sources and partners; and
• Celebrate success.
WHAT DO WE HAVE?61
Integrated Pest Management
Boulder's ecologically based Integrated Pest Management
(IPM) program is a dynamic, decision-making process
that relies on observation and knowledge of the target
organism and the ecosystem where it lives. IPM selects,
integrates, and implements a combination of strategies
to prevent or manage pest populations, including 1)
mechanical control, such as pruning or removal of
diseased or dead trees, 2) cultural, such as proper
irrigation and optimal site choice for tree planting, 3)
biological control, such as releasing natural enemies of
pests, and 4) chemical or pesticide controls.
Boulder’s IPM Program has evolved over the past ten
years and is recognized nationally as an exemplary
program. In 2011, the US Forest Service recognized
Boulder in the National Response Framework for
Thousand Cankers Disease (TCD) of Black Walnut.
Boulder Forestry staff has been invited to speak at
national and regional conferences. Federal agencies
and several national industry groups have convened in
Boulder to tour emerging pest sites and learn firsthand
from the experiences of Boulder’s forestry staff.
Boulder Forestry coordinates closely with Boulder’s IPM
Coordinator. Monitoring activities, early detection, and
rapid response efforts of both public and private trees
are key components of the IPM Program. Monitoring
activities include visual surveys, trapping (with or
without pheromones), and destructive sampling at
the time of tree removal. Generally, the earlier a pest
problem is detected, the more options are available
for management. Unfortunately, current staffing levels
often limit opportunities for field inspections and follow-
controls to improve the health of public trees and
therefore reduce the chance of attack from insect and
disease pests. Methods include better species selection
during the development review process, increasing
tree diversity, proper tree placement, monitoring
contractors for proper planting techniques, and mulch
rings to promote a healthy growing environment and
systematic pruning rotation.
ups are infrequent. The backbone of IPM monitoring is
the annual Tree Health Survey, a citywide survey of all
trees that can provide early detection for potentially
life-threatening insect and disease outbreaks. The
survey allows staff to detect tree health trends on a
block, neighborhood, and citywide scale.
Trees under stress are more prone to attack from insects
and disease. Although stress cannot totally be eliminated,
there are cultural controls. Boulder Forestry uses these
Dr. Whitney Cranshaw and Dr. Ned Tisserat from
Colorado State University examining a walnut tree with
Thousand cankers disease.
The walnut twig beetle and Geosmithia fungus.
Dr. Ned Tisserat leads a Thousand cankers disease
training in Boulder.
WHAT DO WE HAVE?62
In Boulder, the primary IPM control is mechanical via
tree removal, as it is often the only or best management
option for many insect and disease pests, such as Dutch
elm disease. Forestry staff has removed or had removed
per city ordinance over 1,000 trees since 2005 infected
with TCD of walnut, DED, or ips beetle in spruce to
prevent spread to other trees.
Boulder’s IPM Policy directs that pesticides be reduced
or eliminated wherever possible. Most pesticides are
banned on city properties, where the majority of
Boulder’s public properties either have no pesticides
applied, or pesticides are minimized and strategically
applied as a last resort.
Tree pest management, particularly for exotic pests,
can be challenging since trees support a wide range
of biodiversity and other species can be affected by
pesticide treatments. Management decisions are based
on the severity of the pest and its threat to tree health
and the urban forest. In cases where pesticide use is
required to protect the life of trees, and the overall
environmental benefits from preserving trees are
estimated to outweigh the impacts to non-target species,
pesticide treatment plans are carefully designed to
mitigate non-target impacts as much as possible.
Pesticide application guidelines for Forestry include:
• Pesticides are used only as a last resort, when the
health of trees is threatened, alternative controls
are not available, and/or pesticides are the BMPs
for an invasive pest;
• Trunk and soil injections are used whenever
possible to reduce pesticide drift and minimize
public contact; and
• Only the least toxic available pesticides are used
and over time alternatives have been found that
further reduce toxicity levels.
Many alternatives utilized by Boulder Forestry are not
the industry norm. To continue to identify the least toxic
chemical controls and to utilize a variety of control
options, Forestry staff must continue collaboration
with outside agencies on projects to evaluate controls.
The existing ordinance allows property owners to
treat adjacent public street trees but only with city
authorization. Most frequently, the property owners
who treat the adjacent public street trees do not
communicate with or get approval from the city. Boulder
Forestry and the IPM Program have relied on outreach
and education to provide information to the public
about the impacts of pest control decisions on public
health and the environment. More options, including
legal methods, need to be explored and developed to
assist the public in complying with the ordinance.
Protecting Pollinators
To protect bees and other pollinators, city staff
collaborated with Bee Safe Boulder (now merged with
People and Pollinators Action Network) on Council
resolution No.1159, 2015, which banned neonicotinoid-
active ingredients on city-managed parks, playing fields,
ROW, along watersheds and ditches, open space lands,
public trees and other areas under city jurisdiction.
It allows for their use on trees if tree health is
threatened, but, it requires a formal exemption from
the city manager.
Honeybee hives are preserved whenever possible
during tree care operations. Beekeepers are contacted
to relocate hives, or, if the timing is right, hives are
relocated to the Forestry woodlot where they can safely
swarm.
The pollinator program provides external resources to
become a citizen scientist and help track native bees
through the Bees’ Needs project at CU. Bumblebee
sightings are tracked in the Xerces Society’s Project,
BumbleBee. The city also launched the Boulder Pollinator
Garden Project to work with public, private, and non-
profit partners and homeowners to encourage the
creation of high-quality pollinator habitat throughout
Boulder, both on public and private properties.
The city provides outreach and education about
pollinators and other biodiversity issues by hosting
Pollinator Appreciation Month each September. Partners,
such as CU, local NGOs, and volunteers, offer a variety of
events, culminating in the Bee Boulder Family Festival.
This festival is attended by hundreds of children who
learn about the importance of pollinators through fun
and creative activities.
WHAT DO WE HAVE?63
Emerald Ash Borer Mitigation
Ash trees provide considerable economic, environmental,
and socio-economic services to community members.
Unfortunately, EAB was discovered in the City of Boulder
in 2013. Boulder was the first city in Colorado to identify
EAB and is at the forefront of the state’s management
program. Ash is one of the most abundant tree species
in urban areas across Colorado, including 12 percent of
Boulder city parks and ROW trees by numbers. Boulder’s
ash trees contribute approximately 25 percent of the
overall canopy cover. The estimated number of public,
private, and naturalized ash in Boulder is over 70,000
trees at an estimated value of $18 million.
The Forestry Division has six main themes for EAB
management in Boulder:
• Protect public safety and minimize liability;
• Maintain a healthy, diverse, and sustainable
urban forest;
• Maintain or increase the urban tree canopy
to maximize the environmental, social, and
economic services provided to Boulder;
• Minimize risks to non-target organisms from
pesticide applications;
• Minimize costs; and
• Minimize disruption to other forestry operations.
EAB Control Methods in Boulder
After the initial discovery of EAB in Boulder, the USDA
Animal and Plant Health Inspection Service (APHIS),
the agency responsible for the federal EAB quarantine,
declared EAB in Colorado as an “incident” equivalent
to a wildfire and instituted an Incident Command
System (ICS). The ICS allowed all affected agencies to
share communication while developing mitigation and
management strategies and outreach materials for EAB
in Colorado. The EAB ICS was in place from September
2013 through April 2015, where it transitioned to the
Colorado EAB Response Team. Agencies participating
in the EAB ICS and the Colorado EAB Response team
include: APHIS, Colorado Department of Agriculture
(CDA), City of Boulder, Boulder County, University of
Colorado (CU), Colorado State Forest Service (CSFS),
and Colorado State University (CSU).
To slow the spread of EAB in Colorado, the CDA imposed
a quarantine on the movement of all ash tree products
and hardwood firewood out of Boulder County.
To assist staff with EAB monitoring and management,
Boulder Forestry consulted with two of the leading
national EAB researchers and two local experts in
entomology and tree pest management: Dr. Deb
McCullough, Michigan State University; Dr. Krista Ryall,
Canadian Forest Service (CFS); Dr. Whitney Cranshaw,
Colorado State University; and Dr. Sky Stephens, U.S.
Forest Service. The group provided research documents,
guidance on EAB strategies, and information on possible
differences in EAB behavior in Colorado.
Since initial detection, over 1,350 public ash trees have
been removed from Boulder’s urban forest. Additional
A 2015 study session with the City Council garnered
unanimous support for Forestry’s proposed long-term
management strategy. Boulder management components
include:
• Planting;
• Removals;
• Pesticide applications;
• Biocontrols;
• Quarantine;
• Outreach and engagement; and
• Wood debris management.
Emerald Ash Borer (Adult)
WHAT DO WE HAVE?64
ash removals are currently behind schedule when
Boulder Forestry had to adjust priorities and focus on
the removal of more than 500 dead Siberian elms, which
had been killed by a November 2014 freeze event.
Approximately 5,300 public ash trees remain in city parks
and ROW. Boulder Forestry is treating approximately
25 percent of the remaining public ash trees through
pesticide application in a three-year rotation, where
the remainder will be removed over the next several
years. To manage this transition, Forestry staff
members are proactively removing ash trees that are
near ash exhibiting symptoms of EAB, in poor condition,
or poorly placed (e.g., under power lines). Ash trees
in development projects are also being phased out
when possible, including private development and city
projects (e.g., Transportation, Parks and Recreation,
and University Hill General Improvement District Capital
Improvement projects).
Pesticides
Boulder’s EAB strategy complies with the city’s Integrated
Pest Management Policy and takes into account non-
target effects, environmental impacts, and long-term
objectives. Pesticides must be evaluated prior to use
and are only used if other options are not feasible.
Forestry staff assessed four commonly used pesticides
utilizing data from the EPA and other regulatory agencies,
advice from leading experts in EAB management, and
open literature. The decision-making process for EAB
treatment is complex due to differences between
products, diverse use rates, multiple methods of
application, timing of applications, pest control efficacy,
and environmental considerations.
impacts from TREE-äge. In 2014 and 2015, TREE-äge was
applied to public ash trees within the known infested
areas in a targeted strategy. This product will continue
to be evaluated as more information becomes available.
As local EAB populations decline due to mortality in
untreated ash trees, it is likely that the number of trees
will be reduced each year for both products.
More than 25 percent of Boulder’s public ash trees meet
the criteria for EAB treatment. All public requests for
pesticide applications are being tracked by Forestry
staff. Feedback from contractors suggest that many
homeowners are treating ash trees, but only a small
percent report these activities.
The analysis of pesticide options indicates that
imidacloprid, a neonicotinoid insecticide, posed a high
risk to pollinators and other non-target organisms, while
showing inconsistent efficacy for EAB control. In March
2014, Forestry and IPM staff recommended that the
city manager prohibit the use of imidacloprid for EAB
control on city properties, including public street ROW.
Two products are currently being used by Forestry staff
for EAB management: TREE-äge and TreeAzin, a “semi-
synthetic” tree injection and a natural tree injection.
There are knowledge gaps about each of these products,
and Forestry staff is seeking partnerships and research
opportunities to investigate potential environmental
Control Method: Application of Pesticide Control Method: Biocontrol (Parasitic Wasp Eggs)
WHAT DO WE HAVE?65
state quarantine took effect on November 12, 2013 and
a federal quarantine was enacted in April of 2014.
CDA enforces the quarantine by entering compliance
agreements and inspecting arborists, woodworkers,
firewood dealers, and others handling regulated articles.
Regulated articles include EAB specimens, ash nursery
stock, ash logs, branches and chips, green lumber, all
hardwood firewood, or any other article, product, or
means of conveyance that may present a risk of spreading
EAB. The sale and movement of regulated articles out
of a quarantined area are prohibited. Movement of
regulated articles, other than nursery stock, is allowed
if the regulated material meets certain specifications
verified during inspection.
Existing city code, B.R.C. Chapter 6 Protection of Trees
and Plants, 6-6-2 Removal of Dead, Diseased or Dangerous
Trees allows the city to enforce regulations for dead ash
trees located on private property where there is the
potential to threaten public property. Forestry staff,
Boulder Police Department, and the City Attorney’s
Office are coordinating to enforce the removal of dead
ash trees on an as-needed basis.
Forestry begins enforcement actions with letters,
phone calls, and other communication. If there is
no compliance, Forestry collaborates with the City
Attorney's Office and Boulder Police Department for an
administrative warrant to allow a contractor to enter
onto private property to remove the tree.
Forestry anticipates that current staffing levels will
not be sufficient to support enforcement efforts as EAB
reaches its peak.
Biocontrols
Four species of non-stinging parasitic wasps have been
released in Boulder to combat EAB. Additional releases
are planned over the next few years. Two of the
species have been found in traps, which is proof that
they are successfully reproducing and overwintering in
Colorado. The long-term goal for natural enemies is to
suppress EAB populations in the post-outbreak phase. If
effective, this could result in a reduction in the amount
of pesticides applied in the future.
Quarantine
EAB and many other pests are dispersed through multiple
pathways, including movement of nursery stock and
firewood. Firewood is a raw forest product that is widely
utilized and moved throughout the U.S., with relatively
limited consideration of the potential for pest dispersal
or the associated risks.
To restrict movement of pests, federal and state
quarantines prohibit the transport of firewood and other
ash wood materials outside of quarantined areas.
Because EAB is a federally quarantined pest, APHIS
works with state cooperators to detect, control, and
prevent the human spread of EAB. To restrict intrastate
movement of regulated articles, including live plants
and wood from ash and EAB, the Colorado Department
of Agriculture (CDA) has imposed and is enforcing a
quarantine on the movement of all ash tree products
and hardwood firewood out of Boulder County. After
discussions with local trash haulers, CDA also included
small portions of Jefferson and Weld Counties to gain
access to two landfills within the quarantine area and
control flood debris and EAB-infested material. The
WHAT DO WE HAVE?66
Public Education / Outreach / Engagement
Education and outreach are critical components of response to an invasive tree pest. Emerging Pests in Colorado (EPIC) and the
Colorado EAB Response Team are two inter-agency working groups formed to increase industry and public awareness about invasive
pests. Participants included staff from the CDA, CSFS, CSU, APHIS, and foresters from several cities including Boulder, Denver, and Fort
Collins.
Multi-agency efforts to raise industry and public awareness about the threat of EAB and other invasive pests since the EAB detection
include:
• Websites: CDA has posted educational material about EAB on their website: www.EABColorado.com. A website was created
for Boulder specific EAB information at: www.EABBoulder.org and a hub to engage the community specifically on EAB and
resiliency was created at www.resilienttogether.org/emerald-ash-borer.
• News Releases: The CO EAB Response Team and City of Boulder have distributed over 30 news releases and handled over 100
media requests since the EAB discovery.
• EAB Workshops: Boulder Forestry hosted a series of EAB Identification and branch peeling workshops in 2013, 2014 and
2015 and a series of EAB Van Tours in 2016 and 2017. The interagency group has trained over 550 foresters, arborists, and
landscape professionals from six states on EAB symptoms and branch peeling techniques.
• Presentations: EAB presentations to Parks and Recreation and Environmental Advisory boards, the Downtown Management
Commission and City Council. Meetings with over 30 local HOA groups to discuss EAB management;
• Open Houses: Hosted three EAB specific open houses for the public in 2014 and prov ided EAB tables at the two UFSP open
houses in 2017 and 2018 and informational tables at Farmers Market and McGuckin’s on multiple occasions.
• Educational material produced: Emerald Ash Borer Quick Guide, EAB Decision Matrix, Revised Edition of Insecticide Options
for Protecting Ash Trees from EAB, Colorado specific EAB FAQ’s, EAB identification cards, utility billing inserts, and RTD bus
advertisements.
• Launched TreeOpp program: Community awareness/engagement wood utilization program repurposing ash wood into lumber,
art, furniture in partnership with BLDG 61, Bridge House and ReSource.
• Tree Give away and sales: Launched first annual Boulder Tree Recovery Program in 2017 with support from National Arbor Day
Foundation – gave away ~250 1-5gallon trees to residents to plant on private property. Facilitating and subsidizing the sale of
15 gallon trees to residents in 2018 and beyond.
• Seedlings for BVSD 5th graders: Each spring Boulder Forestry provides a short educational presentation to BVSD 5th graders
on the importance of our urban tree canopy, the potential impacts of EAB and explains how they can make a difference. Each
student also receives a seedling tree to plant for future generations to enjoy.
• Tree Planting Events: Hosted multiple community volunteer tree planting events since 2013 at locations around the city.
• Tree Trust: Partnered with the PLAY Boulder Foundation to launch a Tree Trust.
• Home and business owner contacts: Reaching out to individual residential property owners and downtown commercial
business owners as opportunities arise to replace declining public ash trees though letters, door hangers and newsletters.
EAB Outreach and Engagement
Education and outreach are critical components of
Boulder’s EAB management strategy. Forestry staff has
collaborated with other city departments and outside
agencies to increase outreach efforts. Boulder Forestry
is proud to have developed effective EAB workshops
and dissections for private industry and other forestry
stakeholders. In 2016, Boulder hosted EAB tours in
cooperation with the Colorado EAB Response Team.
Participants included foresters and City Council members
from nearby communities. The response to this tour was
positive and Boulder hosted tours again in July of 2017.
Consistent with long-term department goals, Forestry
will continue to implement strategies that “Take Care of
What We Have” and proactively engage in “Community
Building” as a method to address the sustainability
of Boulder’s urban tree canopy. Staff will continue to
explore additional opportunities to increase awareness,
collaborate on community tree plantings, identify
environmentally sensitive methods for managing wood
debris, and focus efforts to increase investment in tree
care and replacement over time.
WHAT DO WE HAVE?67
17%
14%
12%
0%
2%
4%
6%
8%
10%
12%
14%
16%
18%
2000 2005 2015% of AshEven prior to the EAB detection,
Boulder Forestry had begun to
reduce the percent of public ash due
to improve tree diversity. The overall
percent of public ash decreased from
17% in 2000 to 15% in 2005 to 12%
in 2013 through selective removals
and diversification in replacement
plantings.
Wood Debris Management
With the discovery of EAB in 2013, Boulder became an
EAB quarantined community, where hardwood wood
waste from the community was required to be disposed
of in designated areas within and on the border of the
County. Also, it is a violation of state and federal law to
improperly dispose of wood waste. All UFRs generated
through maintenance operations are diverted from
the landfill. Wood utilization options that have been
implemented or explored include:
• TreeOpp: Boulder partnered with BLDG 61
Makerspace at the Boulder Public Library to provide
expert woodworking training for participants
in Bridge House’s Ready to Work program. The
program teaches participants to turn EAB-infested
wood debris into crafts, furniture, and functional
products, for purchase by area residents;
• Biomass: Boulder entered into an agreement with
Boulder County to utilize chips from whole trees
as a quality heating fuel. Boulder County owns
and operates two heating systems (biomass fueled
boilers) at the Boulder County Parks and Open
Space facility in Longmont, as well as the Boulder
County Jail in Boulder that burns woody biomass
to heat its buildings;
• Mulch/Composting: Tub grind logs into mulch,
which is then utilized within the city park system
or moved off-site for composting;
• BioChar: Charcoal is used as a soil amendment to
improve soil quality. Biochar is a stable solid, rich
in carbon, and can endure in soil for thousands
of years. Biochar can increase soil fertility of
Tree Replacement
A variety of tree species, including western catalpa,
hackberry, swamp white oak, London planetree, English
oak, and sugar maple are among the species recommended
to replace ash and increase diversity in the urban forest.
Since ash removal began, Boulder Forestry has decreased
the percent of public ash from 17 percent in 2000,
to 14 percent in 2005, to 12 percent in 2015 through
diversification in replacement efforts (Chart 11).
From 2014 through 2017, Boulder Forestry planted 1,935
trees in city parks and public street ROW in support of
Boulder’s no-net-loss canopy goal. Efforts were made to
plant trees in neighborhoods most heavily impacted by
EAB. The UFSP is proposing a goal for Boulder Forestry
to plant 600 new trees annually. It is important to note
that the success of newly planted trees requires a strong
commitment to a frequent and effective pruning rotation
cycle.
Boulder is planning a Spring 2018 tree sale of 15-gallon
trees with tree costs subsidized via Public Works Water
Conservation, the Climate and Sustainability Division
and the Parks and Recreation Department. Boulder is
also continuing the National Arbor Day Foundation Tree
Giveaway of seedling trees through the Natural Disaster
Recovery Program.
To kickstart the no-net-loss canopy strategy on private
property, Boulder Forestry mailed letters to property
owners in neighborhoods heavily impacted by EAB,
encouraging property owners to request trees through
the Boulder Forestry tree planting program. Letters
were sent to property owners with good planting sites,
including those with enough public ROW to support
a large-maturing tree, an irrigation system, and no
overhanging trees. The letters included information
about Boulder’s tree replacement program and the
benefits of urban tree canopy and offered to plant a
tree in the ROW adjacent to the home for free.
Chart 11: Ash as % of Public Trees
WHAT DO WE HAVE?68
acidic soils (low pH soils), increase agricultural
productivity, and provide protection against some
foliar and soil-borne diseases; and
• Lumber: Higher quality logs are set aside for local
sawmill operators to mill for furniture or flooring
or to sell to the public via ReSource.
The EAB quarantine makes it illegal to move any
hardwood firewood outside of Boulder County due to
the difficulty in identifying ash from non-ash after it has
been cut to firewood size. All residents cutting firewood
must sign a liability waiver and agreement stating wood
will not be moved outside of Boulder County.
Department Strategy and Collaboration
Boulder’s EAB Interdepartmental Strategic Team works to
identify and implement long-term strategies to manage
EAB on a citywide scale and to ensure consistency across
departments. The team includes representatives from
the departments of Open Space and Mountain Parks,
Public Works, Transportation, Planning, Greenways,
Risk Management, Police and the City Attorney’s Office.
Boulder developed a delimitation survey that found
EAB in several neighborhoods in central Boulder. The
site area was divided into 38 one-square-mile grids
and ten trees were selected randomly in each grid
for inspection. Additional trees were sampled in high-
impact areas. For each selected tree, two branches
were removed, and then examined by extension agents
by painstakingly peeling each log into paper-thin layers
using a draw knife. The city successfully identified
EAB in several grids, and has updated its findings with
continued research. Currently, EAB is expected to be
present everywhere in the city.
Initial EAB management actions included news releases,
website postings, HOA meetings, educational materials,
workshops, and television interviews. Over the next two
to five years, EAB will have a significant direct budgetary
impact on Boulder and private residents. Unless
immediate actions are taken to replace the anticipated
loss to canopy (~25 percent of existing canopy), the
transformed canopy will have considerable economic,
social, and environmental impacts for decades. Because
the majority of the trees in Boulder are on private
property, tree replacement will require a coordinated
effort between Boulder Forestry and the community.
All untreated ash trees on both public and private
property and naturalized areas along the creeks and
ditches are expected to die from EAB over time. Since
EAB detection, Boulder has planted over 1,900 new trees
in city parks and street ROW. A canopy loss of up to 32
percent is expected in some Boulder neighborhoods due
to EAB. Although considerable, the overall loss to the city
urban tree canopy is not as great as expected losses in
other Front Range communities that are predominantly
green or white ash.
Boulder Forestry staff participate in the emerging pests
in Colorado (EPIC) working group and the Colorado EAB
response team to share strategies, conduct workshops,
develop templates for management plans, and keep
apprised of advances and challenges in pest detection
and management.
The EPIC committee includes city foresters from
Denver and Fort Collins, as well as input from other
relevant regional agencies. EPIC’s goals are to increase
cooperation and communication around emerging pests
and diseases. This endeavor includes public education
and outreach, which is a crucial component of EAB
management, through workshops and the development
of management plan templates.
Over the next few years, proposed EAB management
strategies, including tree removal, tree replacement,
wood disposal, and pesticide treatments, will continue
to have a significant direct budgetary impact on Boulder
and private residents.
WHAT DO WE HAVE?69
Commercial Tree Program
Boulder’s Commercial Tree Program (CTP) monitors
and maintains public trees in the downtown area and
other commercial areas throughout Boulder, including
sidewalk treatments (tree grates, tree pits, and pavers)
associated with those trees.
The program only receives funding to provide services
for the downtown trees, which includes: installing and
maintaining tree grates (construction of supporting
frames, leveling grates and pavers with surrounding
sidewalks to minimize trips, expanding grate rings to
allow for tree growth, and repairing or replacing broken
panels or guards), installing tree guards as needed
for tree protection, tank watering of trees without
supplemental irrigation systems, tree replacement,
and negotiating with commercial property owners to
improve site conditions.
In 2000, Boulder Forestry collaborated with the Planning
Department to revise the design and construction
standards for tree grate construction to standardize the
sizes and styles of grates and to require the installation
of supporting frames. Funding was granted to the
program in 2005 from patio lease revenues to allow for
hardscape repairs, and additional funding was added
in 2008 at the request of City Council to include tree
replacements in the downtown area.
WHAT DO WE HAVE?70
Because trees vary considerably in life expectancy,
growth habit, and maintenance requirements, an
accurate inventory is crucial for strategic planning. Asset
management is used to track the status and history of
each inventoried asset, including new and replacement
plantings, tree condition, maintenance needs, work
history, and individual tree reports and photographs.
On a broader scale, the software can help plan
maintenance operations and provide analysis for
Tree Inventory and
Asset Management
One of the key themes from BPRD’s recent Master
Plan is, “Taking care of what we have.” Through
the development and implementation of an Asset
Management Program (AMP), the department intends
to manage data and provide support for all facets of
Forestry operations. The result will be a well-informed
organization that prioritizes decisions and resources
supported by a robust database.
In anticipation of the transition to an AMP in
2012, Boulder purchased DRG’s TreeKeeper® asset
management software to consolidate the tree inventory
and improve tracking for tree maintenance activities.
Forestry staff rely heavily on TreeKeeper®’s mobile
applications for data collection. Despite the benefits of
the software, there is currently no option for offline
data collection (cellular connection in West Boulder is
spotty).
Over the past 30 years, the number of public trees has
increased steadily. In 1987, the original public tree
inventory was collected in a spreadsheet format and
contained information on 27,000 trees. An update in
2000 included 36,000 public trees, where the addition of
location data provided the first tree layer for Boulder’s
GIS program.
The most recent inventory update (2015) collected
data on 50,800 trees and included additional data fields
to track tree grates and guards, along with pest and
disease metrics that will inform long-term strategy for
EAB management and the UFSP.
species diversification and budgeting for tree-related
expenditures. In addition to a current inventory, it is also
important to maintain up-to-date maintenance records
on each tree for liability purposes and budget tracking.
There is also a public interface that includes valuable
calculations on environmental services provided by each
public tree.
For logistical reasons, Parks and Recreation (including
Forestry) is transitioning to a partnership with Utilities
to use a single citywide asset management system
(Beehive).
WHAT DO WE HAVE?71
All new development
and redevelopment,
meeting specific
minimum
thresholds, are
required to provide
street trees.
These requests include:
• Determination on whether a tree is public or
private;
• Requests to remove public street trees (outside
of a development review process); and
• Tree appraisals for construction projects and
enforcement issues (outside of development
review).
Mitigation fees are tracked through Boulder’s software
and account payments systems. Planning staff typically
adds the amount due under a building permit and the
responsible party can pay the Planning and Development
walk-in service counter, which ensures consistent
accounting history.
Development Review, Tree
Protection, and Mitigation
Planning and Forestry staff works closely together to
review development proposals, including single-family
residential, multi-family, mixed-use, and commercial
development. All new development and redevelopment
projects that meet specific minimum thresholds are
required to provide street trees. Forestry staff reviews
development landscape plans to ensure compliance
with Design and Construction Standards (DCS).
Recommendations are provided for species selection
and spacing, removal of undesirable trees, methods to
minimize impacts during construction, and tree value
appraisals for desirable trees that are scheduled for
removal.
The development process includes “by-right” projects
that request no modifications to the land use code
and “discretionary” review projects that do request
modifications. Discretionary review may be approved by
city staff, the Planning Board, or City Council, depending
on the specific request. Coordination occurs throughout
the process and includes:
• Requests to remove trees through a development
review process;
• Project specific and appropriate tree protection
standards;
• On-site inspection pre-construction to determine
feasibility of preservation, assess conditions, and
determine specific requirements associated with
protection/preservation;
• On-site inspection during construction to assess
tree protection and condition changes;
• On-site inspection post-construction to review
damage, mitigation and condition;
• Private tree assessments for development review
projects when needed to support staff concerns
or discrepancies in arborist supplied tree
inventories;
• Requests for project history to determine
obligations of private property owners;
• Maintaining tree inventory for removals and new
planting;
• Planning staff typically recommends and reviews
tree species selections, but does ask Forestry
staff for input as needed; and
• Subject area experts as needed.
Forestry also responds to requests from adjacent private
property owners (especially single-family residential).
Silva cell installation on Pearl Parkway for the Boulder
Junction project.
WHAT DO WE HAVE?72
Challenges to the existing process typically occur
around city projects that are not subject to the DCS or
Title 9 standards. This includes inconsistency in Boulder
Forestry’s role and authority to make determinations
on tree removal. For permitted projects (e.g., civic
area redevelopment, private developments), Boulder
Forestry is responsible for evaluating trees that will
potentially be impacted by the project.
The actual decision to remove individual trees is up to
Boulder’s project managers, not Forestry, and there
is no requirement for justification. For non-permitted
projects (e.g., playground refurbishments) Forestry
takes a more active role in determining removal for
individual trees.
All transportation capital projects coordinate closely
with Forestry and staff has the opportunity to provide
input on tree removal and replacements. Yet, ultimately
tree planting and removal decisions are made by the
project managers.
Other challenges include:
• Current DCS are outdated in regard to application to
city projects, tree species, planting specifications
and diversity. They allow only small-maturing trees
to be planted into ROW strips less than six feet.
• Inefficient tracking and communication between
work groups.
• Construction oversight for tree protection and
additional landscape review taxes Forestry staff
and siphons resources away from core Forestry
programs, such as the TSIP, CTP, IPM, and Rotational
Pruning.
Fixed-term staff was hired in both Public Works and Parks
and Recreation to manage the construction aspects for
additional CIP projects after the 2011 Bond initiative, but
most projects had both existing public trees within the
project area and new landscape planned. Construction
oversight for tree protection and additional landscape
review taxed Forestry staff for several years and took
resources away from core Forestry programs such as the
TSIP, CTP, IPM and Rotational Pruning.
WHAT DO WE HAVE?73
Enforcement of Tree Regulations
B.R.C. Chapter 6. Section 2 Removal of Dead, Diseased
or Dangerous Trees allows city staff to conduct
enforcement efforts on private property to address
infested, diseased and/or dangerous trees. During
summer months, Forestry staff surveys all city parks,
streets, and alleys to identify diseased and dangerous
trees on both public and private property. When
forestry staff identifies a violation, a compliance case is
initiated, and the property owner is notified with a first
class letter. Forestry staff works with the Boulder Police
Department and the city attorney’s office to address
issues of non-compliance. Before a tree care contractor
can enter private property to remove a diseased or
dangerous tree, the city must obtain an administrative
warrant from the court. The cost of tree removal is
billed to the property owner and, if needed, a lien
placed against their property taxes. Existing feedback
from the community is that Boulder Forestry must be
that number increased to approximately 100 trees for
dangerous trees, mainly due to EAB and dead Siberian
elms from the 2014 freeze event. In 2017, the number
of enforcements was just under 150 trees.
The ordinance currently allows Boulder Forestry to
give the property owner “fifteen days from the date
of the notice or such shorter time as the manager
finds appropriate in view of the nature and extent
of the condition.” Local tree care companies have
experienced significant increases in requests for work
and have been unable to remove trees within the
15 days required by the ordinance. In many cases, it
has taken 30+ days to get these dying/dead ash trees
removed, thereby increasing public safety concerns. To
minimize risk, starting in 2018, Boulder Forestry will
enforce on private property ash trees with less than 50
percent crown symptoms. Removing symptomatic ash
while still green should also lower removal costs as ash
trees that exhibit >50 percent crown symptoms must
be removed with specialized equipment that increases
removal costs.
Ash trees along Greenways pose another concern. Green
ash is naturalized (to various degrees) along all creeks
and ditches in Boulder. With the exception of Boulder
Creek Path, Public Works manages trees along bike paths
adjacent to Greenways, therefore, Boulder Forestry
does not currently survey these areas for dangerous
trees. Due to the proximity of bike paths, tree removal
or enforcement should be expected (depending upon
whether it is public or private property) as trees die.
It is anticipated that current staffing levels, even as
supplemented by contractors, will not be sufficient to
support enforcement efforts as EAB reaches its peak.
more proactive in communication to allow property
owners more time for tree removal before the trees
becomes a high risk.
Over the next several years, the number of dangerous
trees is expected to increase significantly as ash trees
are killed by EAB. Research indicates that ash trees killed
by EAB dry out and start to fail within a few years after
tree mortality, posing a public safety risk. Discussions
with the City Attorney’s office, Risk Management, and
Boulder Police Department, indicate Boulder has a duty
to enforce city regulations for dead ash trees located on
private property but that have the potential to threaten
public property. Boulder is not proposing to implement
enforcement efforts on private property where the trees
only pose a threat to neighboring private property.
Between 2010 and 2015, Forestry enforced on an
average of 20 properties each year to address diseased
trees and an average of 25 properties for dangerous
trees that posed a threat to public property. In 2016,
WHAT DO WE HAVE?74
Arborist Licensing and
Staff Training
Boulder Forestry is recognized for their expertise and
proactive approach to urban forest management.
To better protect all trees, a licensing program was
created to ensure that all tree work (public and
private) performed within the city limits of Boulder is
conducted to the same standards. Forestry and Planning
staff work collaboratively to manage the city arborist
licensing program for tree care contractors to ensure
the following:
• All tree work within the city is performed in
a safe, professional manner and according to
industry standards;
• All persons/companies performing tree work
within the city have the necessary insurance;
• All diseased/infested wood is disposed of in a
proper manner to prevent the spread of insect or
disease problems; and
• Maximize environmental services are derived
from the Boulder urban forest.
To ensure that outside contractors meet these
expectations, Boulder created a two-tier arborist
licensing program:
1. Certified Arborist License – for all International
Society of Arboriculture (ISA) certified arborists or
professional-level tree care companies. Licensees
in this category have demonstrated a higher level
of knowledge and professionalism and are allowed
to perform tree work to trees in the public ROW
and to both public and private trees that are
infested/infected with a major insect/disease
problem such as EAB, TCD of black walnut, DED,
drippy blight of red oaks, Mountain Pine Beetle,
etc.
2. Tree Contractor – for all persons or companies
performing tree work that are not ISA certified
or choose not to test through the city. Licensees
under this category are not allowed to perform
tree work to trees in the public ROW or to public or
private property trees that are infested/infected
with a major insect/disease problem.
Under this program, any person or company performing
work to either public or private trees (tree pruning and
tree removal) within city limits must be licensed in one
of two categories; certified arborist or general tree
care contractor. Forestry staff administers testing and
annual training and provides updates on city standards
for licensed arborists.
There are some recognized limitations to this program,
including:
• No requirement to show proof of safety training;
• The current two-tier system is confusing to the
public and stakeholders believe the system should
be only one tier (the top tier); and
• No effective enforcement mechanism for ensuring
compliance with this requirement.
The application process requires numerous modes
of contact, including an e-mail address, and the city
is progressing towards multilingual options for all
information. Boulder Forestry would like to increase
contact with licensees through meetings, newsletters,
and training in hopes of further strengthening the high-
quality standards of tree care in Boulder.
WHAT DO WE HAVE?75
Emergency Storm Response
Boulder Forestry often responds to emergencies
involving trees. This includes public trees that have
been damaged by storms or high winds, involved in
automobile accidents, and vandalized. Forestry also
responds if a private tree falls or drops branches into
the ROW. During and immediately after major storm
events, Forestry staff conduct comprehensive surveys
to identify and prioritize work, including pruning and
removal, to provide clearance and ensure public safety
in the ROW. Forestry and Public Works collaborate to
complete the cleanup. Forestry staff remove damaged
branches in trees and Public Works removes downed
trees and branches. In large storm events, the city
engages contract crews to assist with cleanup and debris
removal.
Although Forestry and Public Works coordinate regularly
during large storm events, there is no formal emergency
response protocol. Sometimes there has been confusion
and misunderstanding of Forestry’s responsibilities and
priorities. As a result, Public Works and Forestry have
each expressed the desire to review policy and develop
protocols to address emergency response, including
storm calibration and plans for the mobilization of
equipment and personnel.
to be inclusive and inviting to all Boulder community
members include:
• Articles in local newspapers volunteer-led tree
plantings in city parks;
• Annual Arbor Day celebration;
• Tree give-away program;
• Seedling giveaway for BVSD fifth graders at the
Water Festival;
• Fall photo contest;
• Online self-guided notable tree tour and
accompanying application for Snow Much Fun
Scavenger Hunt;
• Map your ash tree and replacements; and
• Citizen science project with 100 Resilient Cities.
Door hangers are the primary method used to notify
adjacent property owners of upcoming tree care
operations on their street. Due to the high percent
of rental properties, Boulder Forestry must also send
letters to property owners in addition to the door
hangers. Notification is extremely challenging given the
number of rental properties.
Successful outreach campaigns find ways to give notice
to both owners and managers in addition to tenants. For
high profile projects and when major traffic disruptions
are scheduled, Forestry employs additional methods to
reach concerned stakeholders, including news releases,
social media, flyers, and website resources.
Communication, Public
Outreach, and Notification
As a part of normal operations, Boulder Forestry
maintains active communication lines with multiple
audiences, including the Boulder community, other city
departments, green industry leaders, woodworkers,
regional foresters, and city, state and federal agencies.
The city primarily communicates with residents through
established outreach programs, including, the Boulder
Forestry Newsletter, Emerging Pests in Colorado (EPIC),
and the Colorado EAB Response Team. Methods of
communication include email, workshops, door hangers,
mailed postcards, news releases, public meetings
and workshops, research tours, online resources,
and farmer’s markets and other community events.
Community engagement activities that are organized
WHAT DO WE HAVE?76
Forestry coordinates with local tree care professionals
to provide updates to bid and contract requirements,
information and updates on emerging pests and disease
treatment strategies, and goals for improving species
diversity.
Regionally, Boulder Forestry participates in the
Emerging Pests in Colorado (EPIC) working group and
the Colorado EAB Response Team to share strategies,
conduct workshops, develop templates for management
plans, and keep apprised of advances and challenges in
pest detection and management.
Boulder Forestry recognizes the importance of outreach
and collaboration with stakeholders and understands
that key messages need to be tailored to the individual
needs and concerns of different groups. Stewardship
of the urban forest requires the commitment and
engagement of the entire community, especially in the
face of managing and recovering from the devastation
that is occurring with the invasion of EAB. Forestry
staff and stakeholders have identified opportunities
to improve outreach and communications strategies,
including:
• Updated door hangers, including new messaging
to increase EAB awareness;
• Better and more proactive methods for
communication with property owners for tree
removals on private property;
• Website elements to better engage youth and
schools;
• Increased use of online story maps and other
graphic tools to promote awareness of EAB,
planting goals, and other key messaging;
• Additional contests and events to connect the
community with the urban forest; and
• Stronger EAB messaging so that the public has
clearer idea of impacts.
WHAT DO WE HAVE?77
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2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017Service RequestsYear
Public Service Requests
Public service requests are submitted through an online
portal and have been steadily increasing since 2013.
Prior to EAB detection, Forestry received an average
of 210 requests per year. From 2013 through 2015, the
average was 659 requests per year. In 2016 and 2017,
Boulder Forestry received 853 and 793 requests for
service (Chart 12). These values do not include the 1,621
emergency response requests since 2010. In addition to
online service requests from the public, Forestry also
addresses internal and jurisdictional requests.
Several factors contribute to the increase in service
requests, such as pest problems including EAB and drippy
blight of red oak, deferred maintenance and suspended
pruning cycles, and a rise in requests for clearance and
safety pruning. Severe weather has also played a role,
including the deep freeze that occurred in November
2014, killing more than 500 Siberian elms on public
property and spring snow storms in 2016, which also
caused significant damage to public trees.
Currently, Boulder does not track the rate of service
requests generated from planning staff. For example,
there is no historical record of additional reviews,
construction oversight, tree appraisals, or inspections.
Without this record, tracking changes over time to
create financial forecasts is difficult.
Previously, the turnaround for responding to service
requests was one week. Following the detection of
EAB, response time increased to two weeks. Currently,
the response time for non-emergency requests is one
month.
Chart 12: Approximate Public Service Requests Per Year
WHAT DO WE HAVE?78
Wood Utilization
Across the United States, large amounts of urban forest
residues (UFR) in the form of wood chips, brush, logs,
and leaves are generated by landscape maintenance
and tree care companies, homeowners, and municipal
tree care operations. This debris can have a big impact
on landfill operations and mismanagement of infected
debris can increase the severity and spread of pests and
disease.
Prior to 2005, when TCD of walnut was identified in
Boulder, Forestry hosted an annual firewood sale. The
sales generated little revenue but were successful at
reducing UFR and disposal costs.
When pest infestations made firewood sales impractical,
logs were ground into mulch that was then used in city
parks or moved off-site for composting by an outside
vendor (A-1 Organics in 2014-2016). The grinding and
haul away costs for this program were over $35,000 in
2016 alone and are expected to exceed $50,000 in 2018.
In 2014, Boulder entered into a memorandum of
understanding with Boulder County to utilize chips from
whole trees as a quality heating fuel. Boulder County
owns and operates two biomass fueled heating systems
at the Boulder County Parks and Open Space facility
(Longmont) and the Boulder County Jail (Boulder)
that burn woody biomass to heat their facilities. This
mutually beneficial program supplies the county with
a source of locally generated biomass and provides
a sustainable use for the UFR generated by Boulder
Forestry operations.
In 2016, a grant from the Knight Cities Foundation
allowed Boulder to partner with Bridge House and
BLDG 61 Makerspace, to develop the TreeOpp program.
Bridge House is a local nonprofit that assists individuals
experiencing homelessness. TreeOpp trains and employs
local artisans that tutor apprentices in conjunction with
Bridge House's Ready to Work program. TreeOpp uses
wood from ash tree removals to create marketable
products for the community, including furniture and
crafts.
Today, all UFR generated from Boulder Forestry
operations is transferred to Forestry’s log yard, where
staff strive to use only sustainable practices and
minimize the amount of UFR entering landfills. Since
2000, only two truckloads of wood infected with DED
were diverted to the Erie landfill. All other UFR was
successfully diverted to other use.
Many cities have realized there is no single long-term
solution for managing UFR, and, considering the high
volume and low quality typical of UFR, identifying
sustainable uses is an ongoing challenge. A suite of
plausible options is crucial to effectively manage debris
and minimize costs.
WHAT DO WE HAVE?79
2017 Operating Budget (Forestry)$
Salaries & Benefits - Standard $489,258
Admin - Supplies, Training, Cell Phones, Etc.$33,604
Pruning $167,700
Fleet $105,000
Removals $87,273
Commercial Tree Program (tree grates/guards)$62,000
Salary - Seasonals $70,000
Planting $18,500
IPM $5,000
Subtotal $1,038,335
Capital Improvement Program (EAB)$220,000
Total $1,258,335
Funding for Forestry
Operations
A stable budget allows urban forest managers to program
necessary tree care at the appropriate life stage when it
is most beneficial and cost effective. Public trees are a
vital component of Boulder’s community infrastructure.
Unlike most components, including buildings, and
pavement, the value and services provided by a tree
generally appreciate over time. To realize this potential,
specific maintenance tasks must be coordinated at
critical life stages.
Trees are living organisms, constantly growing and
changing over time and in response to their environment.
There are a number of factors that affect tree health
and structure, including nutrition, available water,
pests, disease, wind, and humidity. While it might seem
like most changes to trees take a long time to occur,
some specific maintenance is critical at certain stages
of life. For instance, young trees benefit greatly from
early structural pruning and training. Major structural
corrections can be applied easily and at a low cost when
a tree is young.
Unfortunately, if left unattended poor structure can
evolve into very expensive issues and increase liability
as a tree matures. At which point it may be impossible
to correct the issue without causing greater harm.
As a public tree nears the end of its useful lifespan,
planning and budgets should provide consideration for
more frequent inspections and eventual removal and
replacement.
Operating Budget
The annual budget for forestry operations is funded
through four primary sources; the General Fund, the
Parks and Recreation $0.25 Sales Tax Fund, the Capital
Improvement Program (CIP), which provides limited-
term funding to address specific goals, and through
reimbursement for trees removed through development
(Tree Mitigation. In 2017, the overall budget for forestry
was $1,258,335, including $220,000 in CIP funding to
address EAB management (Table 8).
A Tree Cost Estimate formula was developed by Boulder
Forestry to determine the cost to maintain Public Works
trees which includes: the cost of replacement planting,
rotational pruning, pesticide applications and removal.
The formula can be adapted for the different life
stages of a tree (Establishment, Growth, Maturity, Over
Maturity) and can assume proactive management (10
year rotational prune, etc). The formula estimates that
the 4,458 trees on lands currently under the jurisdiction
of Public Works require annual maintenance costs of
approximately $75,000 to maintain the trees.
To put these costs in perspective, the overall budget for
Boulder in 2017 was $321,866,000. Forestry’s budget
of $1,258,335 represents less than 0.4 percent of the
overall annual budget for Boulder (Chart 13).
The General Fund and the Parks and Recreation Sales
Tax fund provide the largest and most consistent funding
for Forestry operations. Funding is dependent upon tax
revenue and is subject to social and political will.
Since 2014, the Forestry budget has been supplemented
annually with approximately $220,000 in CIP funding
to address EAB management, including ash removals,
pesticide treatment, tree planting, tank watering,
and wood debris management. Previously, CIP funds
have supported updates to the tree inventory. Funding
from CIP is generally short-term in nature, intended to
address specific issues and goals.
Since 2014, annual funding for forestry operations
(including CIP) has increased by 9 percent. Excluding
short-term CIP supplements, base funding for forestry
operations has only increased from $880,000 to
$1,038,335. Over that same four-year period, the U.S.
dollar experienced inflation by 3.4 percent. As a result,
the actual purchasing power of the forestry budget has
decreased from 2014 levels.
Table 8: Operating Forestry Budget (2017)
WHAT DO WE HAVE?80
Public Works
40.7%
Open Space and
Mountain Parks
10.5%
Police
10.4%
Fire
5.7%
Parks and Recreation:
Other
7.4%
Parks and Recreation:
City Forestry
0.4%
Other
24.9%
Mitigation
Per ordinance, Boulder Forestry receives compensation for
public trees removed or damaged through development
projects, vehicular accidents, and vandalism. Funding is
earmarked for public tree planting and establishment.
The general Forestry budget contains enough funding to
plant approximately 75 trees annually. The mitigation
fund allowed Forestry to plant an additional 200-400 trees
annually. However, the mitigation funding is sporadic
and not a reliable source for long-term planning.
Chart 13: Municipal Budget
Funding Mechanisms in Various U.S. Cities
Special Assessments: One of the most stable sources of funding for urban forestry programs is the special assessment. Some states authorize cities to assess all property owners for specific
public benefits and services such as sewer systems and public trees. The assessment can be levied as a fee per foot of ROW frontage or as a percentage of the property value.
Taxes: Many cities attain funding for urban forestry through special taxes. St. Louis, Missouri implements a property transfer tax and a sales tax (1/2 cent) to supplement forestry operations.
Burlingame, California devotes a portion of a gas tax to urban forestry.
Capital Improvement Projects: A short-range plan, usually four to ten years, which identifies capital projects and equipment purchases, provides a planning schedule and identifies options
for financing the plan. If trees are defined as capital assets, then funds can be allocated to the protection and management of trees during infrastructure and utility projects.
Development Fees: Private property owners in an area that will benefit from development may be required for a proportion share of the public infrastructure required to serve a development.
Trees can be considered public facilities, and the costs to plant and care for them can be supported by these development fees.
Stormwater Fees: Stormwater fees are often implemented through an assessment to property owners to build and maintain stormwater infrastructure. The trees and vegetation of an urban
forest help mitigate stormwater runoff and lessen the burden placed on conventional stormwater infrastructure. Communities like Milwauakee have recognized that the urban forest provides
legitimate stormwater management activity and can be funded by such stormwater fees. With that level of recognition, Milwaukee recently approved a small increase in the stotrmwater
fee, and earmarked it for urban forestry.
Biogenic Utility: A biogenic utility is a utility founded on the services provided by trees. The services can be calculated in dollars, pounds of pollution filtered, gallons of rainwater
intercepted, tons of carbon dioxide avoided, and kWh of energy not used. Denver Water, in Colorado, is the utility organization that supplies drinking water to over a million people. Denver
Water collaborated with the Forest Service, which signed a $33 million cost-sharing agreement for forest management and watershed restoration. The average residential water user will
pay an extra $27 over the course of five years to match the Forest Service’s $16.5 million allocation.
Donations
On occasion, the Parks and Recreation Department
receives donations from individuals and organizations.
BPRD maintains a list of specific projects that would
benefit from donated funding for those who express an
interest. Otherwise, donations are used at the discretion
of the Director to best meet the current needs of the
department, including forestry operations.
Most donations are one-time gifts and as such do
not represent a consistent or sustainable funding
source. Regardless, every donation is appreciated and
acknowledged by a letter from the Parks and Recreation
Advisory Board.
WHAT DO WE HAVE?81
Tree Size Class Park Tree
Pruning
Street Tree
Pruning Removals
1-7" Diameter $104 $56 $142
8-15" Diameter $105 $91 $245
16-30" Diameter $203 $208 $605
31"+ Diameter $379 $397 $1,287
Funding Shortfalls
Ideal funding provides the resources necessary to
support the quality services historically provided by
Boulder Forestry and allows BPRD to meet community
expectations for the care and maintenance of the
urban forest. At current levels, funding shortfalls have
significantly reduced Forestry’s ability to provide regular
maintenance to street and park trees. While funding has
remained somewhat stable since 2014, EAB response
and recent weather events have required managers to
reallocate maintenance budgets to respond to these
emergencies and reduce their impacts on public safety.
As a result, pruning rotations have been extended
beyond the previous interval of eight years (park trees)
to ten years (street trees) (2012).
Deferred maintenance can be expected to have additional
future impacts on operational budgets as trees that are
neglected are more likely to experience damage and
failure during extreme weather events. Neglected and
storm-damaged trees are also less likely to realize their
expected useful lifespan, reducing their overall services
and utility to the community and reducing the overall
benefit to investment ratio for the urban forest. More
importantly, neglected trees increase risk exposure to
Table 9: Average Tree Care Costs (2012-2016)
WHAT DO WE HAVE?82
Glendale (2005)Bismarck (2005)Cheyenne (2005)Boulder (2017)Longmont (2017)Ft Collins (2017)Berkeley (2005)Average
Investment Per Public Tree $13 $18 $19 $20 $31 $44 $65 $30
Total Forestry Investment $276,436 $316,640 $327,897 $1,038,335 $647,400 $2,280,000 $2,372,000 $1,036,958
Total Public Trees (Street + Park)21,481 17,821 17,010 50,800 21,061 52,000 36,485 30,951
Population 220,000 56,234 53,011 107,167 92,852 167,000 104,000 114,323
calculated from the routine operating budget ($1.04
Million) and does not include EAB CIP funding.
Fort Collins and Longmont, two other Colorado
communities, are examined for context. Fort Collins has
approximately 52,000 public trees and a total budget
of $2.28 million. Longmont now manages 21,061 public
trees, and has a base budget of $647,400.
The mean annual salary for highly-skilled Boulder city
arborists is between $61,084 and $ 79,560. The United
States Bureau of Labor Statistics collects data and
regularly develops a mean of all occupations in the
country. In 2014, the mean annual wage was $47,230
while the mean salary for a municipal field arborist
was $47,837. Entry-level positions, seasonal workers,
laborer, clerical, and truck driver jobs were lower. It is
important to note that the cost of living in Boulder is 21
percent greater than the national average, suggesting
that employee compensation should be correspondingly
higher than communities with a lower cost of living.
property and public safety. Trees of different sizes have
different needs for tree care. Boulder has calculated
these average tree care costs (Table 10).
Industry standards in urban forestry suggest that
cities should provide rotational pruning and general
maintenance on a five to seven-year rotational cycle.
Structural and clearance pruning may require shorter
intervals for affected trees.
National Comparison
The most common primary funding mechanism used
for urban forestry programs among municipalities in
the United States is the General Fund (86%) (Hauer and
Peterson, 2014). On average, the General Fund provides
71 percent of all funds used for forestry budgets.
On average, forestry budgets account for 0.52 percent
of total municipal budgets. The average per tree budget
is $31.67. By comparison, Boulder currently invests
$20 per tree and less than 0.4 percent of the overall
municipal budget (Table 10). The $20 per tree value was
Table 10: Boulder’s Urban Forest Budget in Comparison with Other Communities
On average, US forestry
budgets are 0.52% of overall
municipal budgets. To reach
the average, Boulder would
need an annual forestry
budget increase of $497,735.
On average, US
municipalities invest $31.67
per public tree. To reach the
average, Boulder would need
an annual forestry budget
increase of $458,836.
WHAT DO WE HAVE?83
Proposed Budget
To provide the recommended core programs and
responsibilities, Boulder forestry will require additional
funding (Table 11).
Specifically, current funding levels are inadequate to
support:
• Pruning and maintenance cycles: The industry
recommendation is five to seven-year rotation;
• EAB management: The costs for treatment and
removal will continue to rise over the next several
years;
• Traffic control and towing costs are increasing: for
some trees, the traffic control costs exceed the
removal cost;
• A tree planting initiative to preserve Boulder’s
current level of tree canopy cover (16%): The
initiative requires increasing public tree planting
to 600 trees per year and facilitating 2,025 new
trees on private property;
• Planting initiatives should include an increased
level of young tree care. because proper watering
and structural pruning are required to ensure
young trees live to their fullest; and
• Public engagement and programming.
WHAT DO WE HAVE?84
$1,800,000
$1,600,000
$1,400,000
$1,200,000
$1,000,000
$800,000
$600,000
$400,000
$200,000
$-
Boulder Forestry Annual Funding Scenarios
Administration
Rotational Pruning
Tree Removals
Fleet
Traffic Control/Towing
Planting (Public)
Planting (Private Subsidy)
$592,862
$662,862 $732,862
$222,700
$272,700
$350,700$117,523
$178,023
$238,523
$105,000
$105,000
$155,000
$33,750
$42,250
$85,250
$25,500 $7,000
$25,500 $10,000
$35,500 $15,000
Fiscally
Constrained $1.1M
Action
$1.3M
Vision
$1.6M
Table 11: Funding Scenarios
WHAT DO WE HAVE?85
Climate Change and Severe
Weather
Boulder’s extreme weather will continue to impact
the species of trees that can successfully establish and
thrive in Boulder. Climate change will continue to be a
factor due to changes in precipitation seasons and type
(rain, ice, or snow), temperature fluctuations outside
historic patterns, and changes in regional temperature
norms. These changes blur the lines of established plant
hardiness zones and the species that can be grown in a
given region.
Around the world, foresters are reviewing plant
material lists in a proactive effort to ensure that urban
• Ice or snow settled in branch unions can cause
tissue damage and potential for decay and cavity
development;
• Severe weather can damage irrigation systems;
• De-icing chemicals can cause salt burn on foliage
and create undesirable soil conditions. Prolonged
exposure can reduce overall plant performance;
• Trees can fail in wind events and damage
property or adjacent trees as they fail;
• Prolonged drought can cause summer defoliation
and tree mortality if irrigation systems are
not maintained or without adjustment to
accommodate insufficient precipitation;
• High summer temperatures can increase
transpiration rates and require increased
irrigation regimes;
• Warmer winter temperatures may alter dormancy
requirements;
• Reduces the number of chill days, critical for
trees to produce fruit/nut crops;
• Alters reproductive ability because plants
need to flower to reproduce. In order to
flower, they need a trigger, which is usually a
long winter chill; and
• People can see tree damage and develop
concern for remaining healthy trees, leading to
premature removal or unnecessary and overly
aggressive pruning practices.
tree planting efforts result in increased resiliency and
species diversity in anticipation of climate shifts and
escalations in disease and invasive pests.
Storms, severe weather, climate change, and unusual
weather fluctuations can cause significant damage and
chronic stress in the urban forest, including:
• Snow buildup on branches during early fall or
late spring snowstorms can cause excess weight
on branches, which break or form internal cracks
that further weaken branches;
• Cold snaps after trees have just broken bud can
cause defoliation and damage to new tissues,
requiring the tree to mobilize stored resources to
leaf out again in a second flush;
• Extended periods of extreme cold can kill species
that have thrived in the area for decades,
effectively shifting the area into a different
climate zone;
Threats to the
Urban Forest
WHAT DO WE HAVE?86
Extreme weather events can be a challenge to manage
because of their unpredictable duration and frequency.
Fortunately, urban forest managers do have some tools
to prepare for, and reduce the impact of, severe weather.
For example, there is a need for routine adjustments
to irrigation to accommodate weather patterns. It is
important to note that these adjustments are not always
completed, especially on privately managed systems.
Some systems are controlled by smart irrigation
controllers, which monitor evapotranspiration and
adjust irrigation based on real-time data. Storm
response and emergency preparedness plans can simplify
storm response protocol and ensure coordination and
collaboration among departments. The primary tool in
the face of uncertain weather patterns is establishing a
diverse composition of many species.
WHAT DO WE HAVE?87
1990's Boulder
Forestry Cost Type of Event
October, 1991 $51,250 Freeze
March, 1992 $32,045 Snow
September, 1995 $363,710 (Over 3 Years)Snow
October, 1997 $7,000 Snow
February, 1999 $4,000 Wind
It's not easy being a tree;
Severe Weather Events
Extreme weather events can be a challenge for Boulder; high winds, snowfall,
flooding, and temperature fluctuations all pose threats to the health of trees. Tree-
related costs for severe weather events are mainly due to post-storm clean-up and
tree replacement.
Costs are often difficult to fully record. For example, the severe weather events in
October, 2011 had an unknown additional cost for citywide branch clean up. The
severe weather event in March and April of 2016 included an additional $375,000
in citywide branch clean up. Because these branch clean up costs are unknown or
estimates, they are not included in the Boulder forestry cost values for those years.
Key strategies in the face of uncertain weather patterns include the establishment of
diverse species composition along with proactive pruning. Collaboration and planning
among departments is also vital. Emergency response plans are critical to effectively
respond to severe weather events.
Freeze Damage Freeze Damage Snow Damage
1990's Decade Total Cost: $458,005
WHAT DO WE HAVE?88
2000's Boulder
Forestry Cost Type of Event 2010's Boulder
Forestry Cost Type of Event
September, 2000 $2,000 Snow
2002 through 2005 $122,660 Drought
March, 2003 $5,000 Snow
March, 2004 $5,000 Wind
June, 2004 $2,000 Wind
February, 2007 $2,500 Wind
June, 2007 $7,200 Wind
December, 2008 $4,500 Wind
October, 2009 $12,200 Snow
May, 2010
October, 2010
October, 2011
January, 2012
May, 2013
September, 2013
November, 2014
March + April, 2016
$1,500 Wind
$4,000 Wind
$50,000 Freeze and Snow
$29,000 Wind
No Data Freeze and Snow
$25,000 Flood
$300,000 Freeze and Snow
$150,000 Freeze and Snow
Drought Damage Wind Damage
2000's Decade Total Cost: $163,060
2010's Decade Total Cost: $559,500
WHAT DO WE HAVE?89
been controlled through biological control, but control
of this pest is dependent upon preventing introduction
and early detection.
Thousand Cankers Disease
TCD currently threatens millions of black walnut trees
across the U.S. The disease is caused by the combination
of a fungus (Geosmithia morbida), which is vectored
by the walnut twig beetle (Pityophthorus juglandis).
The disease was first observed in Boulder in 2003 and
is considered to be native to the southwestern U.S. Its
range has expanded greatly over the past two decades
(Sitz, 2017). Treatment or control measures have not yet
been identified, but voluntary quarantine of suspected
infected material is advised.
Detecting infection can be difficult. Sometimes the
infection can persist for years with no external signs or
Other Invasive Pests & Diseases
Invasive pests and disease, including EAB, are one of
the most significant threats to urban forests around
the world. The impacts from invasive pests can be
both environmentally and economically devastating.
Invasive pests are not new to the Boulder landscape.
DED was introduced into Colorado in the 1970’s and first
discovered in Boulder in 1978. Over the past 40 years,
Boulder has removed more than 1,000 American elms.
Across Colorado, approximately 30,000 have been lost
to DED. Other pests that have resulted in tree mortality
in Boulder over the past ten years, or are expected to
cause tree mortality in the near future, include: EAB,
TCD of walnut, drippy blight of red oak, Japanese
beetle, pine wilt nematode, and ips beetle in spruce.
The urban ecosystem and insect/disease problems
associated with it are constantly changing. Looking at
the history of insect infestations in Boulder, it is likely
that new insects that cause damage to Boulder’s urban
trees will continue to be introduced in future years.
Gypsy Moth
An additional threat to the Boulder landscape is the gypsy
moth (Lymantria dispar). The moth was introduced to
the Northeastern U.S. in the 1800s and has since steadily
increased its range. Today, its distribution is primarily
east of the Mississippi with outbreaks in Michigan and
Wisconsin. The moth is the most important defoliating
caterpillar in North America, affecting a wide range of
shade trees and shrubs. Infestations could be especially
devastating to trees already weakened by drought
stress.
The moths are primarily transported in the form of egg
masses attached to nursery plants, firewood, outdoor
furniture, campers, or trailers that originate from areas
where gypsy moth is present (Camper and Cranshaw,
2013). The gypsy moth has been introduced to Boulder
and other parts of Colorado in the past and reintroduction
is possible with a highly mobile population that could
transport the eggs from gypsy moth infested parts of the
country. Previously, gypsy moth spread in Colorado has
Gypsy Moth Caterpillar
Thousand Cankers
WHAT DO WE HAVE?90
symptoms. Walnut twig beetles tunnel into the bark and
introduce the fungus, which then kills an area under the
bark, known as a canker. When the beetles are abundant,
cankers can girdle twigs or branches, stopping the flow
of sugars through the phloem, and causing yellowing,
wilting, and branch die back. Trees under stress usually
die within three years of initial symptoms.
Since 2003, approximately 900 walnut trees have been
removed in Boulder due to TCD. There are less than 100
black walnut trees remaining in city parks and ROW and
most are less than ten inches in diameter. Since the
disease complex only damages a small area under the
bark, the walnut wood can be milled and used to create
useful and beautiful wood products.
Kermes Scale and Lonsdalea
Enterobacteria
Kermes scale (Allokermes galliformis) is a common insect
pest associated with northern red, pin, and gambel oaks
(Quercus rubra, Q. palustris, and Q gambelii). Typical
symptoms include reduced tree vigor and twig die back.
Kermes scale alone is rarely fatal to trees.
In 2010, new symptoms, including sap weeping and
dripping exudate, were observed on dying northern red
oaks. Further testing found the scale associated with
a bacterial pathogen (Lonsdalea quercina), which was
infecting trees and causing the new symptoms.
Susceptible oaks account for 912 trees in Boulder’s
public tree inventory, but there are many more on
private property. Boulder Forestry monitors public oak
trees, providing pruning and removal as needed. Larger
diameter red oaks were also sprayed with Ecotrol
(rosemary oil) in 2016 in an attempt to control the
scale. It is likely more mature northern red oaks will
be removed unless a reliable, effective control can be
found.
Signs of Drippy Blight Canopy Dieback due to Drippy Blight Kermes Scale
WHAT DO WE HAVE?91
Emerald Ash Borer
EAB, a small metallic-green jewel beetle which feeds
on ash trees, is thought to have been introduced to the
U.S. in the mid to late 1990s through wooden shipping
or packaging materials originating in China. It was first
detected in Michigan in 2002 and since then has moved
across the country to over 30 states and two Canadian
provinces. To date, EAB has killed hundreds of millions
of ash trees, and that number is increasing rapidly.
Annually, EAB spreads only short distances (0.5 to six
miles) through the natural dispersal and flight of adult
beetles. EAB has also spread through the movement of
infested material such as firewood.
North American ash trees have shown little resistance
to EAB and it is widely considered to be the most
destructive forest pest in North America, threatening
all native ash trees of the Fraxinus genus.
EAB was likely introduced in Boulder through infested
firewood around 2008. In late September 2013, Boulder
Forestry staff discovered an EAB infestation within the
city. The beetles were detected by staff when sampling
a dead ash tree prior to its removal. This was the first
detection of EAB in Colorado and to date, the western-
most occurrence of this invasive pest in North America.
A subsequent inter-agency survey showed EAB was well-
established within Boulder at the time of discovery.
Forestry staff and local arborists have been treating
larger diameter (>9” DBH), healthy ash with pesticides
as one defense against EAB. This prophylactic approach
will reduce the impact of EAB in individual trees where
the treatment is applied. EAB is 100 percent deadly to
ash trees that are left untreated.
Currently, ash trees comprise 12 percent of Boulder’s
public trees and this percentage is estimated to be the
same for private property. Over the next five years,
EAB is expected to reduce Boulder’s urban tree canopy
by approximately 25 percent (776 acres), reducing the
overall canopy cover from 16 percent to 11 percent. The
impact of EAB will have considerable economic, social,
and environmental impacts for decades. To date, the
cost of EAB management, including tree removal, tree
replacement, wood disposal, and pesticide treatments
has already impacted the Forestry budget and diverted
resources from routine, necessary operations.
Bark removed by woodpeckers searching for emerald
ash borer larvae and pupae.
WHAT DO WE HAVE?92
Distinctive “S” shaped curves indicate that EAB larva
have fed on the interior of the tree.
"D" shaped holes are formed when the adult EAB beetles
exit the the branches and trunk of the tree.Forestry staff sampling an ash tree with EAB symptoms.
WHAT DO WE HAVE?93
EAB Impact
In terms of invasive forest pests, EAB may well represent
the worst-case scenario. EAB management differs from
other invasive tree pest management strategies in five
major ways:
1. Mortality of susceptible hosts: There is very little
resistance to EAB in North American ash species.
Researchers have found almost 100 percent
mortality in most species of ash and especially
green ash, which is the prevalent ash species
across Colorado. EAB also kills ash trees quickly;
at high EAB populations, EAB can kill mature trees
in one to two years.
2. Scope of infestation: There are more trees
susceptible to EAB than any other invasive pest
to date. DED in Colorado killed approximately
30,000 American elm trees over a 40-year period
and threatened 200 million elms across the U.S.
EAB threatens 1.45 million ash trees in the metro
Denver area alone and threatens an estimated 7.5
billion ash trees across the U.S.
3. Difficulty in detection: Evidence indicates EAB
is typically established in an area for three to
eight years before discovery. Since beetles attack
in the upper canopies first; at low populations,
trees often do not show symptoms until several
years after initial infestation. There is no
available pheromone for trapping purposes and
EAB symptoms are similar to those of other insect
pests and environmental problems.
4. Speed of infestation within community: EAB
populations expand exponentially. Mated female
beetles produce 40-70 eggs on average but can
produce more than 200 eggs. Populations can
therefore expand quickly before detection.
Midwest cities report that without the use of
pesticides, all ash within a community are dying
after just ten to twelve years from introduction.
5. Public safety risk: Ash trees killed by EAB dry out
and start to fail within a year of mortality, posing
a risk to public safety and becoming costlier to
remove, as arborists must use special equipment
and techniques when stability is compromised.
Ash is one of the most abundant tree species in Colorado
comprising approximately 15 percent of all deciduous
trees in many urban areas. At the time of detection
approximately 12 percent of Boulder's public trees were
ash. Assuming a similar percent of private trees, the
estimated number of public, private and naturalized
ash in Boulder is more than 70,000 trees.
WHAT DO WE HAVE?94
0.4 inches in diameter. Creamy white
egg that turns to amber. Eggs are laid
from mid-June and well into August.
Females deposit their eggs individually
on ash trees, between layers of outer
bark, and in the cracks and crevices
of the trunk and major branches. Eggs
hatch in about two weeks.
Egg
Adult
Larvae
Pupae
0.25 to 0.6 inches in length. Long,
metallic, emerald green bodies. After
one to two weeks, these new adults
chew D-shaped exit holes in the bark
and emerge from the ash trees. Adult
emergence starts in late May and peaks
in June. Adults must feed on ash leaves
to mature. They start mating after about
one week and laying eggs in three weeks.
0.25 to 0.6 inches in length. During
April and May of the next year, the
overwintering mature larvae will pupate
inside their pupation cells and gradually
transform into adults.
1 to 1.25 inches in length. The new
larvae tunnel through the bark to the
cambial region and feed on phloem.
Phloem is a thin layer of tissue beneath
the outer bark that conducts sugars and
other nutrients throughout the tree.
Without the ability to transport sugars
and nutrients, the tree dies.
7 - 10 Days
1 Year
1 Month
1 - 3 Weeks
Emerald Ash Borer Life Cycle
WHAT DO WE HAVE?95
Development & Growth
In many communities across the U.S., land development
threatens urban tree canopy, especially when parcels
include high-quality established trees. Another
challenge to tree preservation is site management on
construction projects. Tree preservation of private
mature trees, although a priority for city staff is not
necessarily a priority for private developers. As a result,
long-term survival for these trees is often not attained.
When trees of appropriate species are found in good
health and condition, developers are encouraged to
retain them. It's Important to recognize that significant
barriers exist, including:
• Young trees on development sites are improperly
placed;
• There is a lack of specialized care for young,
newly planted trees;
• There are requirements for ongoing maintenance
to ensure private trees reach a mature size and
structure, but there are enforcement challenge;
• Irrigation systems are not maintained;
• Dead trees are not replaced; and
• Regulations require planting but not
maintenance; if trees die in the first year, there
is no follow-up.
thus planning for employee growth and development is
a high priority.
The planning process for the UFSP revealed few
inefficiencies in Boulder’s urban forestry program and
those that were identified are generally beyond the
control of staff, including budget shortfalls and external
threats from severe weather and invasive pests.
EAB, severe weather, and climate change are important
considerations when planning for a healthy and resilient
urban forest. Mortality estimates for the combined
assumptions of standard tree mortality and mortality
from pests is a 25 percent reduction in canopy within
the next decade if proactive measures are not taken.
A comprehensive tree planting initiative to meet the
community’s goal of no-net-loss of tree canopy is a high
priority for the UFSP. Ongoing adaptive management
and monitoring success are cornerstones to building an
even more resilient urban forest for future generations.
Increasing species diversity and protecting existing
healthy trees are crucial to preserving Boulder’s urban
forest and the contribution of trees and canopy to
quality of life and sustainability of the community.
Industry BMPs recommend routine tree pruning be
conducted every five to seven years. Since 2012, due
to safety pruning and removals necessitated by unusual
weather events, pest invasions, and increasing costs for
contact services, the routine pruning cycle has increased
to 11 years for park trees and 15 years for public
street trees. This has created a backlog of deferred
maintenance and an increased number of annual service
requests from the public. Deferred maintenance is far
more critical than simply responding to more service
requests. More than 67 percent (13,034) of young trees
The City of Boulder is well aware of the importance of
trees and urban forests to the health and sustainability
of the community. Boulder Forestry staff exhibit a
high level of expertise and dedication to managing the
community’s urban forest assets and they are supported
in their education and professional development.
Boulder Forestry has assembled a strong foundation
for managing urban forest resources and operations.
Forestry staff use a robust asset management system to
track the condition and history of every public tree, plan
work, conduct threat analysis, and develop informed
management strategies. A GIS-based land cover map
provides information about the location and extent
of existing canopy and a platform for development
of a comprehensive planting plan. A current resource
analysis details the structure, condition, value, and
environmental and socio-economic services provided by
the public tree resource. This information provides a
basis for long-term planning and establishes benchmarks
for measuring the success of management strategies.
Boulder Forestry is recognized nationally for
demonstrating leadership and best management
practices. The existing forestry program is very
progressive, with a diverse range and depth of services,
including annual tree inspections, tree risk evaluations,
maintenance and safety pruning, integrated pest
management, and community outreach. It is important
to note that many of the highly-skilled leadership
positions within Boulder Forestry are nearing retirement,
Conclusion
WHAT DO WE HAVE?96
(<6” DBH) are medium and large-maturing trees that still
have a lot of growing to do before they reach maturity.
Structural pruning is critical at this stage to prevent
costly issues and branch failures as these young trees
mature into their final size in the landscape. Deferring
maintenance affects the health and safety of trees,
results in additional failures during severe weather
events, reduces the lifespan of trees, and increases risk
to people and property.
In the past, staff were conducting safety inspections on
approximately 100 trees per year. Due to the advanced
age and size of trees in older neighborhoods, that number
is now 200 to 250 trees per year. This presents another
challenge concerning evaluation and monitoring,
especially for the TSIP and newly established trees.
Risk of trees in the TSIP are currently much lower than
trees 20 years ago because the highest risk trees were
already removed. The scope of the program represents
a significant logistical burden on Forestry operations and
may need to be scaled back to keep up with demand.
The City of Boulder has a proven track record of
interagency collaboration, as demonstrated by the
interdepartmental EAB response. Two key challenges
exist for coordination and collaboration efforts among
Boulder departments. The first challenge is clarifying
the expectations of workgroup roles and department
jurisdictions when facing an emergency response
event. There are multiple workgroups within and
between departments who play a key role in emergency
response protocols and decision making. Furthermore,
the characteristics of an emergency event will differ
dramatically and will sometimes change which group
takes on the role between these varying emergency
To provide the recommended level of care for the
community's urban forest resources, Boulder Forestry
will require additional funding. Specifically, current
funding levels are inadequate to support:
• Pruning and maintenance cycles: The industry
recommendation is five to seven-year rotation;
• EAB management: The costs for treatment and
removal will continue to rise over the next several
years;
• Traffic control and towing costs are increasing: for
some trees, the traffic control costs exceed the
removal cost;
• A tree planting initiative to preserve Boulder’s
current level of tree canopy cover (16%): The
initiative requires increasing public tree planting
to 600 trees per year and facilitating 2,025 new
trees on private property;
• Planting initiatives should include an increased
level of young tree care because proper watering
and structural pruning are required to ensure
young trees live to their fullest; and
• Public engagement and programming.
scenarios. While there are a few emergency plans in
place, disaggregating which workgroup does what
throughout all potential emergency scenarios that
Boulder might face will continue to be an ongoing
challenge. It is important to continue collaborating
with departments to define and plan for varying
emergency events that will impact the urban canopy.
This is especially true with Public Works, as this has
been identified as a critical department to work with in
the face of emergency response planning.
The second challenge is synchronizing software
and database management tools to be congruent.
Currently, there are several different tools employed
among different teams which increase technological
miscommunication. Beehive has received positive
feedback from the stakeholders who use the software.
Community outreach and public perception are high
priorities for Boulder Forestry. Nationally-lauded
workshops and presentations, combined with an
informative and easy to navigate website, provide the
community with educational opportunities.
In recent years, cost of living increases, mounting
public expectation for service delivery, and stagnant
organizational budgets have created some gaps
between public expectations and service capacity.
Emerging urban forest threats, changes in climate, and
community growth are obstacles to maintaining the
high level of service expected by Boulder residents. In
many cases, challenges can be viewed as opportunities
for development and increased efficiency.
WHAT DO WE WANT?97
PHASE ONE
Background Research and Analysis
PHASE TWO
Technical Needs Assessment and Analysis of Information and
Goal Establishment
Emerald Ash Borer (EAB) Long Term Strategy
- Detection Efforts
- Emergency Response
- Interdepartmental EAB Strategic Group
Initial Tree Canopy Data Collected
What did we do…
• Surveys..over 300 responses
• Interviews with stakeholders, forestry experts and city officials
• Tree Story Stations...over 100 submissions
• Open House...approx. 200 attendees
• Working Group Session- three sessions over 8 months
• Youth Opportunities Advisory Board Presentation
• Growing Up Boulder – Youth Engagement
Who did we hear from….
• Residents
• Neighborhood Associations
• Commercial and business organizations
• Education community
• Non-profit organizations
• Environmental organizations
• Government organizations
Public Tree Inventory Documented
- All Public Park and Street Trees
Inventoried
- Inventory Data attached to
Asset Management Software
All Public Tree Maintenance
Tracked
Urban Forest Resource Analyzed
- Structural Characteristics
Collected
- Baseline Data Derived
Advisory Boards Updated
Urban Forest Strategic Plan
Kicked-Off
- Consultants Selected
- Technical Advisory Team
Identified
- Public Engagement Plan
Developed
Tree Stories Collected
Stakeholders Interviewed
- Internal
- External
Surveys Taken
- Technical
- Public
Urban Tree Canopy Assessed
- Overall Canopy Cover Calculated
- Canopy Potential Determined
- Forest Fragmentation Identified
- Carbon Storage Calculated
- Annual Benefits Calculated
- Priority Planting Sites Identified
Public Open House
Community Working Group (3 meetings)
DRAFT Urban Forest
Strategic Plan Reviewed
Public Open House
Advisory Boards Updated
- City Council Updated
- Community Working Group
- Consulted
Youth Water Festival
Tree Give Away with National Arbor Day Foundation
Volunteer Tree Plantings
Remaining to be accomplished in 2018:
- Final Urban Forest Strategic Plan to be
Developed
- Advisory Boards to be Updated
- Presented to Parks and Recreation Board
for Consideration of Approval
- City Council Presented with Information
Packet
Remaining to be accomplished in 2018:
- PLAY Boulder Foundation’s Tree Trust
Initiative Kick-off Event
- Tree Give Away with National Arbor Day
Foundation
- Youth Water Festival
- Volunteer Tree Plantings
- Discounted Tree Sale
PHASE THREE
Action Plan -Recommendations, Priorities and Implementation
Strategies
PHASE FOUR
Draft and Final Plan Development and
Consideration by Parks & Recreation Board
201820162014201520132017
PLAN PROCESSCOMMUNITY ENGAGEMENTOur Trees. Our Legacy.
Branching Out
Community Input
Outreach for the UFSP focused on two stakeholder
groups; managing stakeholders (those who plan for,
maintain, or manage the public urban forest) and
the community at large. Each of these groups is a
crucial partner in a successful urban forestry program.
Every stakeholder has unique goals and insight that
contributed to the development and priorities of the
UFSP. Two Forks Collective coordinated with Boulder
and DRG to develop a phased outreach process to
determine the community’s views about current needs,
trends and attitudes about urban forestry programs as
What Do We
Want?
WHAT DO WE WANT?98
well as assist in the development of relationships that
will support the long-term stewardship of Boulder’s
urban forest. The public engagement process included
qualitative and quantitative methods for outreach and
engagement, including:
• Stakeholder Long Form Survey
• Community Short Form Survey
• Tree Story Stations
• Tree Speak Public Open House (2)
• Working Group Meetings (3)
• Feedback from the Youth Opportunities Advisory
Board (YOAB)
• Interviews with stakeholders, forestry experts
and city officials
The following is a summary of the public input received
on key issues for Boulder’s urban forest and the forestry
program. A full accounting is available in the Community
Input Report (2017) developed by Two Forks Collective.
Surveys
Long-Form Survey
For the long-form survey, the consultant team and
Boulder Forestry identified key stakeholder groups
that were important to get feedback from on current
forestry issues. These groups included representatives
from local businesses, neighborhood associations, local
arborists, youth and community groups, non-profits,
and education. The survey was sent out via email from
Boulder Forestry to key contacts from these stakeholder
4. To determine if knowledge of Boulder Forestry’s
activities is influenced by certain variables, such
as demographics, residency, and values.
5. To understand stakeholder willingness to engage
in tree stewardship activities, and which
factors may influence this willingness, including
identifying groups most and least willing to
engage in tree stewardship.
Short-Form Survey
As Boulder Forestry expressed the desire for the
survey to reach a larger selection of residents, a short
version of the survey was developed that only included
questions on residents’ attitudes and knowledge about
Boulder’s urban forest, Boulder Forestry activities,
and their willingness to engage in tree stewardship.
No demographic, current environmental activities, or
current attitudes and level of engagement in city issues
were included. The goal of the survey was to get a
general snapshot of attitudes and values around these
questions from a slightly larger sample, but without
identifying which groups to target in order to reduce
the length of the survey and increase the response rate.
The short-form survey resulted in 290 responses.
This survey analysis looks at findings from the five goals
of the long-form stakeholder survey to help inform the
development of the UFSP, findings from the short-form
survey and how they compare to the long-form survey,
initial themes that emerged from the tree storytelling
workshops held in the fall of 2016, and themes from
the Davey key informant surveys and interviews. This
report also compares the findings from the surveys
to larger, statistically-significant surveys conducted
groups after an initial phone call to describe the project.
The email included a brief description of the project
and a link to the survey. All responses were anonymous,
though participants were given the option to include
contact information if they were interested in being
contacted further about the project. The survey was
conducted in the fall of 2016 and resulted in sixty-two
responses total. While the survey is not a randomized
sample, and therefore generalizations about the
responses are limited, the use of validated questions
in larger community surveys allows for comparisons of
these responses to the general population.
The survey asked a combination of questions to better
understand stakeholder’s beliefs, values, knowledge
and attitudes about the urban forest, Boulder Forestry
and their activities, their views about their community,
the environment, current issues in urban forestry, and
demographic information. The survey also included
questions on current environmental behavior and their
willingness to engage in tree stewardship. The survey
used a combination of multiple-choice, open-ended,
and validated measures from other Boulder surveys to
allow for comparison.
The long-form survey had five main goals:
1. To understand what stakeholders think and feel
about the urban forest in Boulder.
2. To understand what stakeholders know, think,
and feel about Boulder Forestry’s activities,
responsibilities, and goals.
3. To determine what groups are the most or least
concerned about issues around the urban forest,
including attitudes and values.
WHAT DO WE WANT?99
Gender and Ethnicity
55-64
Age Ranges
65-74
45-54
35-44
25-34 75+
98% of respondents
are whiteWomen
Men
Who answered the long-form survey? How does this compare to
Boulder’s population?
Organization
For those who answered (43/62), 42 percent came
from a neighborhood association, 23 percent from a
commercial or business organization, 21 percent from
the education community, and 9 percent from a non-
profit/environmental organization. Only 2 percent
answered the survey from government.
Age
For those who answered (49/62), over 50 percent of the
respondents were over 50.The high level of responses
for older respondents may also be a reflection of
more time available for community involvement,
especially as over one third of the respondents
were from a neighborhood organization, and is typical
in community outreach efforts.
Education
For those who answered (48/62), respondents were
evenly divided into thirds between having a bachelor,
masters, or doctoral degree, with slightly more having
a bachelor’s degree.
Residency
Given research that has linked residency to increased
likelihood of community involvement and attachment,
the long-form survey also asked respondents about their
residency. For those who answered (50/62), 92 percent
of respondents were residents of Boulder, and over 50
percent (62%) have lived in Boulder for over 20 years.
Being a resident of Boulder from between 2-20 years
was evenly divided around 12-14 percent. The vast
majority of respondents also owned their residence
(88%). For those who answered (48/62), 50 percent did
not have children living at home, which is not surprising
given the older age of the majority of respondents,
while roughly a quarter had children aged 12 or younger
or adults over 65 living with them. When compared to
Boulder’s population, this sample has a slightly longer
residency rate (20 years or more versus an average of
17 years), and a higher rate of home ownership (88%
versus the 53% in the BVCP). The household composition
of the respondents roughly correlates with Boulder’s
household composition, with roughly a quarter of
respondents having either children under 12 or seniors
(over 65) living with them (BVCP).
Contacted further
Lastly, just under half of the respondents (48%) were
willing to be contacted further to participate in a focus
group.
1. What stakeholders think and feel about the urban forest in
Boulder (questions 1-7).
Urban Forest: Definition
When asked about what they defined as the urban forest,
almost 60 percent of survey respondents felt that it
included all trees and woody shrubs in the city, with
20 percent defining it as street and park trees. This is
encouraging in terms of stakeholders understanding that
trees are part of a larger ecosystem, and is reflected in
almost 70 percent perceiving an association between the
urban forest and open space. However, it also reflects
public confusion about Boulder Forestry responsibilities
and tools to address tree health on public and private
property. As only street and park trees are considered
recently in Boulder: the 2014 Boulder Community
Survey, the 2015 BVCP Community Survey and Focus
Group Summary Results, and the 2014 Boulder Parks
and Recreation Department Master Plan. Lastly, this
report offers recommendations for who to target, and
how, for marketing and outreach for the UFSP and tree
stewardship.
Survey Results
Chart 14: Survey Respondent Demographics
WHAT DO WE WANT?100
threatened
beauty
natural
ephemral
nature
lucky important
wise
environment
colorful
colorful
correction serene
work
open
imperative
place
green
time
lifespaceprecious
harmony
ecospace
abundance
artificial
wildlife
health
great
arboreal
varied
thankful
pure
desireable
calming
peacefulfulfilling
cooling
necessarymeaningfulenjoyable
dynamic
love appreciationvital
shade
maintenanceseasons
81% Associating the urban forest with their neighborhood quality
70% Have a
good sense of
community
66% Informed themselves on Boulder’s issues
Positive Impact
on Life
Shade & Amenity
Cooling the City
Sense of place
Other
and the threat of development, which is not surprising
given the priority of the preservation of Open Space
seen in the 2015 BVCP. Respondents were also asked if
they associated Boulder’s urban forest with the nature
surrounding Boulder. This is important since research
shows that urbanites do not always associate urban
nature with ‘nature’, and thus value it’s preservation
and creation less than ‘nature out there’. The majority
of respondents associated Boulder’s urban forest with
surrounding nature and open space (76%). While the
association between urban nature and bigger ‘outside,
untouched’ nature is not always positive-i.e. urban nature
is considered ‘weak’ nature- (Hough, 2004), previous
surveys in Boulder have indicated that there is a strong
identification with and values around environmental
stewardship and the preservation of Open Space (BVCP
and parks MP) among Boulder residents (City of Boulder
and County, 2015). Furthermore, in the 2014 Boulder
Community Survey nearly all the respondents reported
visiting both Open Space and neighborhood parks (City
of Boulder, 2014), which traditionally is indicative of a
higher personal valuation of these spaces. In addition,
Boulder residents have prioritized a unique identity and
sense of place and this has been linked to the quality of
both Open Space and neighborhood and public spaces
(City of Boulder Parks and Recreation, 2014). As trees
have traditionally been associated with a high level of
symbolism and personal attachment (versus grasses for
example) (Pearce, Davison, and Kirkpatrick, 2015), this
may explain why they are highly valued and associated
with larger nature outside the city.
A majority of respondents also somewhat or strongly
associated Boulder’s urban forest with climate change
part of the community urban forest in Boulder (and
under it’s jurisdiction), this presents an opportunity
for Boulder Forestry to clarify roles and responsibilities
with the public, as well as use this general concern as a
starting point for tree stewardship.
Urban forest: Associations and Values
Respondents were also asked to identify up to three
words to describe Boulder’s urban forest. By far the
most common response was centered on beauty, with
serene/relaxing, dynamic/vital, shade, quality of life,
maintenance and threatened, nature, diverse, health
and love following as primary themes. Secondary
themes include references to the seasons, open space,
Chart 15: Survey Respondent Associations and Values
WHAT DO WE WANT?101
Don’t know about code
enforcement, inventory counts,
planning and licensing 34%
Don’t know about emergency
response 43%
Lack of concern over fast-growing
trees to replace current trees 40%
Drought tolerant trees are
important 30%
(44% and 41%). This association again shows that for
these respondents they recognize, at some level,
the link between Boulder’s urban forest and larger
environmental issues. This also reflects one of the 2015
Boulder Valley Comprehensive Plans’ key values, which
is environmental stewardship and action on climate
change.
Urban Forest: Benefits
Neighborhood quality is also linked to neighborhood
attachment and residential satisfaction. These are
important since neighborhood attachment has been
linked to environmental behavior such as recycling, and
therefore potentially tree stewardship (Takahashi and
Selfa, 2015).
Urban Forest: Threats
Almost 80 percent of respondents felt that pests and
disease were a threat to Boulder’s urban forest. This
likely reflects recent efforts by Boulder Forestry to
educate Boulder residents about the threat of pests
and disease, and in particular EAB, to the urban forest.
However, only 51 percent of respondents felt that
climate change was threat to the urban forest, closely
followed by lack of maintenance (44%).
This question also included an ‘other’ category. For the
long-form survey, 50 percent of respondents indicated
that development and construction was a threat to
Boulder’s urban forest, with maintenance, Boulder
Forestry and Boulder’s government also mentioned as
primary themes. Secondary themes included a lack
of awareness of the interconnectedness of ecosystem
services and benefits, pests, pollution, and sprawl/
increasing population.
Boulder Forestry responsibilities it may help to have a
more targeted message about key roles that Boulder
Forestry deems essential for Boulder residents to know
about and that support the UFSP. Similarly, there was a
wide variety in responses about what the top goals of
Boulder Forestry should be, possibly reflecting a lack of
knowledge about what is needed for the health of the
urban forest. This might reflect a lack of awareness or
understanding about the scale and timing of the threats
to the urban forest as indicated by forestry staff, as
well as increased frustration with current maintenance
of the urban forest.
This question also included an open-ended response
option for both surveys. Respondents indicated
that education, maintenance, and pests were key
responsibilities they thought Boulder Forestry should
be responsible for, with some unsure about current
responsibilities or adequacy of services. Secondary
themes included clarifying homeowner versus Boulder
Forestry responsibilities, issues around drought and tree
watering, inventorying and increasing bushes and shrubs
along street frontage and in parks, and uncertainty or
dissatisfaction with current levels of maintenance and
outsourcing.
Urban Forest and Larger Boulder Policy
Respondents’ ambiguity about the impact of climate
change on the urban forest is reflected in respondents’
ambiguity on whether current Boulder policy documents
on climate change, resiliency, and comprehensive
planning had any relationship to the urban forest.
While most respondents felt there was some association
between the urban forest and the BVCP, with 75 percent
feeling that they were or somewhat related, almost equal
numbers did or did not see any relationship between
the urban forest and the climate change plan (32% and
37% respectively). However, Boulder Forestry messaging
about climate change seems to have gotten through to
a higher percentage of their listserv respondents than
the short survey with almost 80 percent of the short
form respondents associating Boulder’s urban forest
with Boulder’s climate change plan. The resiliency plan
was also more associated with the urban forest, with
68 percent perceiving some relationship, but a sizable
percentage (31%) did not see any relationship. This
ambiguity speaks to the need, also identified by Boulder
Forestry staff, for better coordination and collaboration
between Boulder departments on initiatives and
messaging around the role of the urban forest. This
should be helped if Boulder Forestry receives more
sustainable funding and in-house expertise to help them
deal with current and upcoming forestry issues.
2. What stakeholders know, think and feel about Boulder Forestry
activities, goals, and responsibilities (questions 8-15).
Most respondents were somewhat familiar or had
heard of most of Boulder Forestry’s responsibilities.
Given the wide variety of respondent knowledge about
WHAT DO WE WANT?102
Current Maintenance 43%
Current Direction 49%
Boulder Forestry reflects larger 53%
Boulder values
50% / 61%
Interested in being a tree steward
~ Long / Short survey
Satisfaction with current Boulder Forestry Activities
While there is room for improvement, this also speaks
to an opportunity for Boulder Forestry to focus on
targeted, clear goals and messaging, public engagement,
and alignment with
larger Boulder goals
and values more
explicitly through
the UFSP process
and marketing. It
also means that
current opposition
may be from a vocal
minority, not the larger population (at least from this
sample). Similarly, when educated (in the phrasing of
the question) with the reasoning behind the removal of
trees, the vast majority did not like it but understood
that it was sometimes necessary (95%). This is also seen
in the respondent’s feelings about insecticide use; given
the introduction about why it is sometimes necessary in
the survey question, 80 percent were okay with it if
necessary. This speaks to the importance of messaging
and education for Boulder Forestry, and the potential for
insecticide use to be more acceptable with education.
Tree Stewardship
This is promising in terms of the goals of Boulder
Forestry to increase public tree stewardship as part of
the UFSP and to deal with threats to the urban forest.
analysis was also undertaken to determine if there were
any characteristics that could be identified for those
who did not identify urban forestry as important. In
other words, is there a single variable or characteristic
to explain their lack of interest, and how could this be
used in outreach strategies? For question 5, there was
no single variable that could explain respondents’ lack
of concern for the urban forest.
Similarly, there was no single variable that could explain
respondents’ who did not associate Boulder’s urban forest
with climate change, nor those who did not associate it
with their neighborhood quality. As there was a fairly
small percentage who did not show concern for Boulder’s
urban forest (as framed through these questions), this
may help to explain the lack of a single variable or
characteristic to identify these respondents. A larger
sample, or a more representative sample (especially
for traditionally under-represented survey groups, such
as low-income, non-white, and younger demographics),
may yield different results. However, the association of
residential attachment with concern for urban forestry
discussed above can help with marketing and outreach
in terms of associating, through values and imagery,
urban trees with place making and home, attachment
and quality of life. This last quality in particular may
be useful as it has been highlighted as a key value for
Boulder in the 2014 Boulder Valley Comprehensive Plan.
4. Is respondents’ knowledge and feelings about Boulder Forestry’s
activities influenced by certain variables or characteristics?
Another way of asking if Boulder residents are concerned
with the urban forest is to determine how much they
know and feel about Boulder Forestry activities, since
a lack of interest would correlate with a lack of action
Most were interested in moderate maintenance (50%),
with 34 percent not interested or only interested in
one-off help such as tree planting. While the short-
form survey had a slightly higher percentage that was
interested in tree stewardship, this is not surprising
given the assumed higher level of interest and
engagement with Boulder Forestry activities for their
listserv. Also not surprising is a higher percentage of
the long-form survey respondents who felt that Boulder
Forestry should be responsible for maintenance.
With further targeted outreach and messaging Boulder
Forestry may be able to either increase the percentage
of residents interested in tree stewardship or actively
engage those interested in future programs.
3. Which groups are the most or least concerned about issues around
the urban forest, including attitudes and values (questions 5-7).
Understanding what factors may predict concern over
urban forestry in respondents can be important in order
to tailor messaging and marketing for the UFSP. For
question 5, which asked about respondents’ association
between Boulder’s urban forest and surrounding nature
and open space, respondents who had lived in Boulder
for a long time, as well as those who felt at home in
their community, were more likely to associate the
urban forest with larger nature. Trees themselves,
even street trees, are also often associated with strong
emotional and personal connections for residents. This
is supported by the associations with the urban forest
and open comments from the survey addressed above,
as well as the Tree Story outreach.
Given that the majority of respondents indicated
that they were concerned about urban forestry and
associated it with larger environmental issues, an
WHAT DO WE WANT?103
or initiative to find out more about Boulder Forestry
activities. It is also helpful to know which groups are
more likely to know about, and feel good about, Boulder
Forestry activities in order to identify populations that
might be ‘low hanging fruit’ to start with for outreach
and marketing for the UFSP.
Statistical analysis synopsis
To do this, a model comparison approach was used to
identify key indicators for respondents’ knowledge and
feelings about Boulder Forestry and their activities.
First, a single response variable was created by
averaging responses to two questions: Q8, ‘How
familiar are you with the Boulder Forestry responsibilities
below?’, and Q11C, how well respondents agreed or
disagreed with ‘Boulder Forestry’s policies reflect the
values of the Boulder Community’ to create a single
new metric called ‘Knowledge.’ All possible explanatory
variables were then defined, including the demographic
battery from the end of the survey, as well as other
values and attitudes around the urban forest.
Linear regression models were created to assess the
results. A model was created for every combination
of six or fewer variables. This resulted in more than
35,000 potential models. Each model was then ranked
based on its performance and complexity. If any two
models had the same performance, the one with
fewer explanatory variables was deemed preferable.
This ranking was quantified using Akaike’s information
criterion (AIC).
Results
The resulting best-fit model had only two explanatory
variables; ‘TimeRecycled’ and ‘FocusGroup’, which
Statistical Analysis Synopsis
For this analysis two questions were asked: 1)
What factors indicate a willingness to participate
in a potential tree stewardship program Q14, and
2) To what degree would respondents be willing
to participate (i.e. level of tree stewardship)
Q15. For both questions a similar approach was
used as for the above analysis.
For Q14, the explanatory variables included the
demographic variables, the new knowledge metric,
and questions 3, 7, and 11, which asked about
threats to the urban forest, associations between the
urban forest and neighborhood quality, and feelings
about Boulder Forestry’s current activities. These
explanatory variables were included given their
insight into respondents’ feelings about how much
threat Boulder’s urban forest is under (and therefore
Because of the increased number of variables
the number of combinations that could be
explored was reduced, which created a
logistic regression model for all combinations
of five or fewer explanatory variables. This resulted in over
16,000 models.
For Q15, the same approach was taken, with the same
explanatory variables. Because responses to Q15 have
multiple levels, a multinomial logistic regression was
used. Again, a regression was compared for every
combination of five or fewer explanatory variables,
producing 16,000 models.
Results
For Q14, the results show that the key variables
associated with their level of interest in participating in
correspond to Q17A and Q30. Additionally, all of the
top-performing models contain these to explanatory
variables, and in every model these two indicators
have the strongest explanatory effect. When examined
more closely, both of these predictors have a significant
positive relationship with the variable Knowledge. In
other words, the more times per year a person recycles,
the more likely they are to be knowledgeable and
agree with Boulder Forestry activities. Similarly, those
willing to participate in a focus group about urban
forest issues are more likely to be knowledgeable and
agree with Boulder Forestry activities. This is supported
by research that shows that current environmental
behavior is associated with a higher level of knowledge
about environmental issues (Stern, 2000) and pro-
environmental values (Liuna, Jingke, Lijuan, Wenjun,
and Kexin, 2015). Given the high rate of recycling in
Boulder, this may be a good place to start in terms of
targeted marketing outreach.
5. Which factors influence a person’s willingness and degree of
participation in a potential tree stewardship program?
The last analysis focused on identifying what factors
may influence a person’s willingness, and degree of
participation, in a potential tree stewardship program.
This goal was identified in collaboration with Boulder
Forestry given current budgetary constraints, the backlog
of maintenance, and upcoming increased maintenance
with climate change and pests. While the program is
still under discussion and has not been developed yet,
understanding respondent’s willingness to potentially
participate, as well as who might be the most willing,
can be very helpful in marketing and outreach efforts.
WHAT DO WE WANT?104
a tree stewardship program are a) Time spent gardening
(either at home or in the community), b) Education,
and c) Time spent in Boulder (residency). Specifically,
those with a bachelor or master’s degree, who have
lived in Boulder 2-5 years, or 16 plus years, and those
who engaged in gardening activities, were more likely
to interested in participating in tree stewardship. It is
unclear why those who have lived in Boulder between
11-15 years were not as likely, but this could be due
to time crunches, age, and other factors, or just the
sample for this survey. While due to a large standard
error for each estimate no one variable can be assumed
to be significantly indicative of participating in a tree
stewardship program, the best models all contained
these explanatory variables. This means that it is highly
likely that outreach and marketing for residents who
engage in gardening activities (and are thus more likely
to be comfortable taking care of trees and other plants),
who have a moderate level of education, and who are
residents of Boulder will be more effective. It is also
likely that these variables are linked, but the current
data is too messy to determine their relationship.
For Q15, explanatory variables were added to the model
and ranked on its probability that it explains respondents’
level of participation to the question. These levels of
participation are: 1) No response; 2) None of them. This
is the responsibility of Boulder Forestry and should be
covered by current taxes; 3) I would like to help out
but am unable/it’s not feasible to do so; 4) I would be
willing to occasionally water a tree outside my business/
residence/workplace; 5) I would be willing to water
and maintain a tree outside my business/residence/
workplace; 6) I would participate in tree planting; 7) I
would participate in youth education.
home (Q18) as key explanatory variables. This is not
surprising given that those who are more willing to
educate themselves about Boulder Forestry activities,
who agree with them, and who are willing to participate
in a focus group, are more likely to ‘help out’ through
tree stewardship. Similarly, Feeling at home, which is
linked to attachment to one’s community, has been
linked to an increased likelihood of environment action
(Takahashi and Selfa, 2015). Given the priority in the
2015 BVCP over quality of life and sense of place, as well
as links above between trees and neighborhood quality,
it would be prudent to link Boulder Forestry activities
to supporting and enhancing the quality and sense of
place for residents’ neighborhoods as one aspect of the
marketing and outreach campaign. This is particularly
true given the emotional and personal connection many
residents expressed to trees in the Tree Story outreach
and comments in the survey.
Tree Stories
At the same time the long and short form surveys
were underway a broader outreach activity was taking
place in a more creative form. In an effort to get the
community thinking about “trees”, we developed “Tree
Story Stations.” A series of wood boards were created
The most likely response is to not participate (2), which
indicates a bit of an uphill battle to get residents to
participate in a tree stewardship program. However,
comments from the ‘other’ response category in the
long-form survey shed some light on this reluctance.
Many indicated that age and health issues are a barrier
to increased participation, as well as time limitations
and a lack of specific information on specific trees.
This is not surprising given the older age of this sample
population, but can also be expected from residents
aged 30-45 who are more likely to be in the crunch years
of working and raising children. However, since the tree
stewardship program does not exist yes, and would likely
include more specific information on tree watering and
responsibilities, this may increase potential willingness
to participate. There were also comments about trees
in the right of way; some were already watering the
tree on their right of way since they deemed Boulder
Forestry maintenance inadequate, which may reduce
their desire to increase their participation, and many
indicated a desire for a more comprehensive and
clearer stewardship and enforcement program between
property owners, managers, and the city. As confusion
over responsibility for trees in the right of way are
known to Boulder Forestry as on-going issues, it would
be helpful for this to be part of the outreach and
marketing for the UFSP. Comments over the desire to see
a comprehensive, public, and integrated tree inventory
and maintenance program online further support the
need for integrated outreach and education.
For those willing to engage in some level of tree
stewardship, the results show that the best models
all identify a) participating in a focus group, b) the
knowledge variable developed above, and c) Feeling at
WHAT DO WE WANT?105
and temporarily placed in the Main Library, recreation
centers and at local events. People were given
information about the development of the Strategic
Plan and asked to submit stories, photos, drawings or
poems on-site or online, illustrating their connection
to trees. As an added incentive each submission would
automatically enroll you in a monthly drawing for a
variety of prizes from Boulder Parks and Recreation.
Over 100 submissions were shared at the stations
and online by a wide range of community members
including children. The submissions were very moving
and reflected how deeply connected the Boulder
community is to trees. A selection of stories were also
shared in a special display at the public meeting for
other community members to enjoy.
Tree Speak Open House
The initial public meeting hosted at a local public
gathering space, was designed to provide the
community an opportunity to learn about the role of
Boulder’s Forestry Division, an overview of the strategic
plan process, summary of the initial analysis and bring
awareness to the vast number of programs and resources
forestry provides. In addition the event hoped to
capture the community’s response to recommendations
on maintaining and growing Boulder’s urban canopy and
what types of outreach activities that would be most
effective.
Multiple stations featuring specific topics allowed
attendees to either learn individually or engage with
members of the forestry division. Two stations sought
to capture the community’s preference on maintaining
or growing the urban canopy over the next 30 years,
providing options on how to achieve proposed canopy
goals. There were also individual stations devoted to EAB
Awareness, the TreeOpp program, Tree Story submissions
and a demonstration on interactive mapping tools.
The event was well attended, with a wide variety of
participants. Approximately 130 people RSVP’d to the
event, however it was estimated that close to 200
people attended.
1
1,997
-776
Canopy Acres
Acre loss
$634,439
CANOPY LOSS 2037
28% Canopy loss*
Annual Average
Environmental Benefit
PRIVATE
1,960 trees
PUBLIC
10,000 trees
Planting
(trees)
500 ANNUAL
10,000
Planting Investment
$187,500 ANNUAL
$3,750,000
City of Boulder
Planting
Next 20 yrs.
Private: 1500
canopy loss
Public: 497
28% CAN O P Y L OSS
PublicPrivate
NET NEUTRAL 2037
0% Canopy Growth*
2
CANOPY GROWTH 2037
6% Canopy Growth*
3
2,773
0Canopy Acres
Acre loss
$876,155
Annual Average
Environmental Benefit
PRIVATE
40,500 trees
PUBLIC12,000 trees
Planting
(trees)
600 ANNUAL
12,000
Planting Investment
$225,000 ANNUAL
$4,500,000
City of Boulder
Planting
Next 20 yrs.
Private: 2121
Public: 652
0 % CA N O P Y L OSS
2,939
166
Canopy Acres
Acre gain
$931,296
Annual Average
Environmental Benefit
PRIVATE
50,500 trees
PUBLIC
14,000 trees
Planting
(trees)
700 ANNUAL
14,000
Planting
Investment
$262,500 ANNUAL
$5,250,000
City of Boulder
Planting
Next 20 yrs.
Private: 2,204
Public: 735
6% CAN O P Y GAIN
CANOPY GAIN
PublicPrivate
PublicPrivate
Tree Speak Open House | March 9, 2017 | Boulder Urban Forest Strategic Plan | Project lead: Kathleen Alexander, 303-441-4406 9
89%
11%
0%
Canopy Scenarios
WHAT DO WE WANT?106
Station Responses
Canopy Scenarios
Participants were given a graphic overview of Boulder’s
current urban canopy along with information on current
threats and their impact on the canopy over the next 20
years. Community members were then presented with
three scenarios and the requirements to achieve each
outcome presented. Community members presented their
preference for a scenario by voting with a sticker. The
three scenarios presented were canopy loss, net neutral-
no loss in canopy, and net gain-a small growth in canopy
over the next 20 years. 89 percent of those who voted
preferred canopy growth over the other two options.
The community was then asked to provide their
preference on a list of tactics that would help achieve a
net neutral or net canopy gain. Below are the community
preferences for the tactics outlined.
How do we take care of it?
1. Tree Planting Requirements for Private
Projects 21% - Increase the minimum
requirements for tree planting and on-going
care for private development or re-development
projects.
2. Tree Planting for Public Property 15.6% -
The city should plant additional trees on public
lands, in parks and on street rights-of-way.
3. Subsidized Tree Planting for Private Property
14.5% - The city should host a program to help
subsidize the cost of tree planting on private
property. This could include passing on bulk
pricing for trees and/or support in planting trees.
4. Tree Planting Requirements for City Projects
14% - Increase the minimum requirements
for tree planting on city development or re-
development projects.
5. Increased Tree Protection Standards for Private
Projects 12.6% - Tree protection standards exist
for public trees. Add defined requirements for
acceptable tree removals and tree protection
during construction for private property trees on
private development projects.
6. Create a Foundation 11% - The community
should create a foundation to solicit private/
corporate funding to supplement tree planting,
maintenance and/or education.
7. Mitigation Funding for Tree Removal 6% -
Mitigation is required by code for public trees
removed on any development project. Add
a requirement for trees removed on private
property for development projects. Funding
could be ear-marked to support community tree
planting projects.
8. Increased Tree Protection Standards for
City Projects 5% - City development or re-
development projects should have defined
requirements for acceptable tree removals
and increased tree protection standards during
construction.
9. Other Ideas (comments):
• More diversity in tree species
• Full time staff devoted to planting and young
tree care and maintenance
• CSU Master Arborist Program (similar to Master
Gardeners (plus 3 votes)
• Outreach volunteers to help homeowners plant
and care for trees (plus 3 votes)
• More budget money for Forestry
• Plant more female trees to reduce woes of
allergy sufferers. Worth it for diversity.
• Don’t let developers remove trees
Working Groups
Working Group 1
In an effort to collect more in depth insights from the
community and initiate relationships for long-term
stewardship, Boulder Forestry and the consultant
teams, identified eight key stakeholders to participate
in a series of working group sessions. These individuals
included a representative from a local nursery, practicing
certified arborists, neighborhood association members,
a member from a local tree related non-profit, and a
member of Boulder Community Hospital. The working
group participants attended two facilitated discussion
sessions.
The first working group session was designed to familiarize
working group participants of Boulder Forestry activities
and work to date regarding Boulder’s public trees. This
was followed by a presentation of the baseline urban
tree canopy analysis for Boulder, canopy over the next
20 years including EAB and other invasive pests, climate
change, severe weather events and development.
WHAT DO WE WANT?107
• Additional Information: Provide detailed
information to the community on the
maintenance costs associated with each canopy
scenario and how this fits within the city’s
priorities and budget.
The working group was then asked to provide their
thoughts around community wide solutions to preserve
Boulder’s urban tree canopy. Below are the opportunities
the working group identified.
• Using the Boulder Arts community as a model,
the community needs to present to the city their
desire for an additional tax that can be applied
toward efforts to preserve and grow Boulder’s
tree canopy.
• Identify effective tree related non-profits and
emulate their tactics.
• Have the city emphasize the gap that exists
between what is needed to maintain and
grow Boulder’s urban canopy and what can be
accomplished with the existing budget.
Working Group 2
In the course of reviewing the feedback from the
initial working group session, comparisons were made
to other communities with experience implementing
desired programs and strategies. Davey Resource Group
reviewed over 25 different programs considered to
be successful urban forest strategies. Working group
participants were provided these real-world examples
of successful programs across the following topics:
volunteer engagement, resilience and sustainability;
tree planting initiatives, city-non-profit partnership
and tree protection. In the second session the working
group was divided into three smaller groups and given
one of the following topics and questions to focus on:
Volunteer Engagement
• How does this get started and who should be
responsible for management and funding?
• What type of program would be most effective in
Boulder?
• Tree Planting Initiatives
• What challenges and opportunities do you see for
engaging residents and encouraging tree planting
(and care) on private property?
• Should taxpayers subsidize or facilitate tree
planting and care for private property? How?
Tree Planting Initiatives:
• What challenges and opportunities do you see for
engaging residents and encouraging tree planting
(and care) on private property?
The group was then presented with three scenarios that
take into consideration the gap in existing resources for
maintaining canopy given known threats.
• Scenario 1: a 28 percent canopy loss by 2037
• Scenario 2: Net Neutral Canopy by 2037
• Scenario 3: 6 percent canopy growth by 2037.
Working group participants reviewed the scenarios and
provided feedback on how they thought the community
would react to impending canopy loss and what their
preference would be regarding the three scenarios
presented. All working group participants agreed that
establishing a goal to grow the urban canopy was
optimal.
The discussion followed three basic themes:
• Messaging: Improve the city’s messaging
regarding our current canopy, strongly
emphasizing impending threats and their overall
impact over the next 20 years.
• Awareness: Education on the importance of trees
should be presented in the context of tree’s
impact on human health.
“Trees are directly associated to human
health. Clean air is one of the most valued
resources. Messaging should be focused
around health, (trees are) critical for the
health of our children, creating a healthy
environment for our children. It is critical
for human life for trees to exist in our
community.”
~Working Group Participant
“We need to communicate how long
it takes to properly replace canopy in
addition to the loss that is inevitable,
and how taking care of trees can help
maintain the canopy.”
~Working Group Participant
WHAT DO WE WANT?108
allow the community to interact with forest
management.
• Work collaboratively with all other sustainability
and resiliency initiatives that focuses on climate
action, conservation and livable communities.
Tree Protection on Private Property:
• The working group supports the idea of exploring
tree protection on private property and
recognizes that many communities along the
Front Range currently have some form of this
within the city.
• The group understands that tree canopy goals
can’t be met just from planting, we need to
effectively manage and protect existing trees.
• Need to initiate a systematic methodology for
exploring an option for this in Boulder that
is based on science, criteria and evaluation
metrics.
• Could start small with a pilot program and
work towards a comprehensive approach that
would result in smart regs, incentives instead of
penalties.
• Need rigorous engagement and buy-in from
community with an understanding that the
urban canopy doesn’t see property lines and is a
community resource.
Working group participants agreed to continue to be
part of Boulder’s Urban Forest Strategic Plan process
by reviewing the draft plan providing feedback and
recommendations on the strategies outlined.
• Consider innovative and effective marketing
strategies such as leaving dead trees in place
temporarily, illustrating future view corridors
without Ash, etc.
Tree Planting Initiatives:
• The working group recommended that an
advocacy group outside of city staff needs to
champion an initiative to educate, inspire,
mentor and train community members on
planting initiatives, protecting and caring for
trees on private property and how to ensure
sustainability of the urban forest.
• An advocacy group should also consider funding
programs and incentives for tree protection,
planting and maintenance in the form of grants,
discounted nurseries, or consider tax initiatives
to fund forest initiatives similar to other
designated taxes for resource conservation.
• Trees are a critical component of public health,
economic vitality and livability in a community.
They should be prioritized and funded similar to
any other critical infrastructure especially with
the resiliency and sustainability in mind.
• Also consider a long term approach through
changes to development codes to increase
planting or preservation and care of existing
trees on private property.
• Consider an attractive and effective marketing
campaign to increase public awareness through
social media, professional groups, youth
engagement and digital interactive tools that
• Should taxpayers subsidize or facilitate tree
planting and care for private property? How?
Tree Protection on Private Property
• Do you support some level of tree preservation
requirement for private property?
• Would you support a tree removal permit process
separate from the development process?
• Should mitigation (in lieu of preservation) for
private tree removals be allowed?
The outcomes of these smaller focused discussions
echoed may of the recommendations from the first
session while identifying some key components that
were seen as necessary for success. Below is a summary
of key findings for each topic covered.
Volunteer Engagement:
• Focus on the issue of EAB and other critical
threats to the urban forest to provide a “call to
action” in the community.
• Clearly and effectively communicate the
consequences of EAB and its impact on the
forest.
• Encourage community participation through
volunteerism, promotions, fundraising, and
partnership.
• Focus on more “close to home” initiatives such
as working with neighborhood groups, schools,
churches or commercial centers manage and
care for their trees through planting, pruning,
treating, etc.
WHAT DO WE WANT?109
ResponsibilityCity (tax$)50 10 15 20
Partnerships
Community
Timing
A
C D E
B
presentations, school tree plantings,
opportunities for input, etc.
Each overarching goal had 3-4 specific actions. The
working group was asked to discuss the actions presented,
prioritize them in order of importance, specify where
these actions fell on a timeline between 1-20 years, and
designate the level of responsibility between the city,
strategic partnerships and the community. The groups
collective decisions for each action were then charted
on separate maps.
Q1: Establish a no-net-loss urban tree canopy (UTC) goal
through 2037.
ACTIONS:
A Communicate the goal to the community and engage
them in identifying and executing solutions.
B Develop and implement a Public Tree Planting Plan
to achieve the UTC goal. The plan should have
both citywide and neighborhoods specific planting
and diversification targets to increase street tree
stocking with a diverse mix of well adapted species.
C Educate private property owners on diversification
goals needed for large maturing trees and proper
tree maintenance to ensure trees live to maturity.
D Incentivize, educate and partner with private
property owners to provide cost sharing, free
replacement trees or incentives to contribute to
planning efforts on private property.
E Asses canopy cover for progress and adjust planting
and/or preservation goals as needed-recommended
time frame: every 10 years.
Some key comments that came out of the discussion for
goal no. 1 include:
• There is an opportunity for contractors and
commercial arborists to help educate the
general public on species diversity and the city’s
proposed goals. As well as providing educational
support around tree maintenance and care
for both young and mature trees and how
this directly plays into achieving the citywide
preference of no-net-loss UTC.
• Marketing and communication: Benefit of
communication, possibly hiring professional firm.
• Communicating the same message- work with
partner groups to get message out.
• Initiate a Tree Keepers organization to help
Working Group 3
For the third working group exercise, participants
were provided in advance, a draft version of the Urban
Forest Strategic Plan (UFSP) along with a summary of
community outreach efforts to date and a document
outlining UFSP Goals, Priorities and Actions derived
from all of the data and community input gathered thus
far. The session was designed to focus on 7 goals where
the working group would have the most impact. Below
are the seven goals in no particular order or ranking.
1. Establish a no-net-loss urban tree canopy (UTC)
goal through 2037
2. Create an Urban Forest Emergency Response
and Drought Plan including overall citywide
coordination and clean-up efforts.
3. Updates to city codes and policies to better
protect public and private trees to achieve the
UTC goal.
4. Establish and increase funding and staff resources
to support all Forestry maintenance operations
to desired community level of service for urban
forest management.
5. Explore the establishment of a partner non-
profit urban forest foundation or “tree trust”
to leverage additional financial and community
support for the urban forest.
6. Develop a community-led volunteer program
focused on urban tree canopy.
7. Continue existing and develop additional youth
engagement programs including educational
WHAT DO WE WANT?110
ResponsibilityCity (tax$)50 10 15 20
Partnerships
Community
Timing
A
C
B
with maintenance and promptly recognizing and
recording harmful pests.
• Partner with a non-profit organization that can
provide the educational programing needed
through a stable volunteer base.
• It is vital to have educated neighborhoods to help
generate buy-in and participation in helping to
achieve the stated UTC goal.
• Focus funds on educating the community rather
than providing free replacement trees. Free
trees don’t always establish a strong foundation
for continued care and maintenance.
• Examine possible incentives for rental property
owners to help maintain and care for trees on
their properties.
Goal 2. Create an Urban Forest Emergency Response
and Drought Plan including overall citywide
coordination and clean-up efforts.
ACTIONS:
A Develop an Urban Forest Emergency Response Plan
including overall citywide coordination with clear
role clarification among departments and criteria
for different levels of pruning and citywide cleanup
efforts.
B Educate property owners about trees and drought so
they can be prepared and know what to expect when
water restrictions are enacted.
C Coordinate with Utilities Division to develop a
Parks Drought Plan that establishes priorities and
appropriate amount and timing of irrigation per tree
species per park site based upon science and research
based horticultural Best Management Practices.
Some key comments that came out of the discussion for
goal no. 2 include:
• Bring back ‘Spring Clean-Up Day’- a former
citywide effort
• Ensure that tree maintenance education is shared
across all existing vehicles of communication
(email/newsletters/social media).
• Look at Fort Collins Emergency Response Protocol
as an example to emulate.
• Educate and communicate is a resonate need in
the plan, there needs to be “someone” whose
job it is to do this. The city should exploit every
city opportunity to communicate need to water
and tree maintenance- it will affect everyone.
Goal 3: Updates to city codes and policies to better
protect and maintain public and private trees to
achieve the UTC goal.
ACTIONS:
A Revise licensing requirements for Certified Arborists
performing tree work in Boulder (may include shift
from existing two-tier to single Certified Arborist
License, require proof of safety training, educate
all licenses on pertinent city codes, develop
enforcement mechanism to ensure company
compliance with all licensing requirements, etc.).
B Start community dialog on appropriate updates
pertaining to trees on Public Property:
i. Develop Park Design and Construction Standards,
update Tree Protection (for public street trees),
Diversity and Streetscaping requirements in
the City Design and Construction Standards and
ensure consistency.
ii. Develop pesticide application permitting system
for private treatment of street trees similar to
City of Denver requirements. Ensure industry
best management practices are followed for
the maintenance of all public and diseased
trees. Update code to address enforcement and
penalties
iii. Review current ordinance and policies for
public tree protection and strengthen where
appropriate.
WHAT DO WE WANT?111
ResponsibilityCity (tax$)50 10 15 20
Partnerships
Community
Timing
A
C
B
iv. Update codes to add appeals process for
enforcement of tree nuisance abatement on
private property and lengthen the time frame for
remedy to timeframe appropriate for tree and
site conditions.
v. Update codes to improve and enforce long-
term maintenance of landscape requirements
on private property including provisions for
inspection and enforcement. Add personnel
necessary to oversee and monitor tree protection
in construction on public property.
Some key comments that came out of the discussion for
goal no. 3 include:
• These actions would require a 2-year public
engagement process similar to the process that
occurred under the Boulder Zero Waste Plan.
iv. Enforce existing requirements for irrigation and
mulching for public street trees by adjacent
property owners.
v. Prioritize the upgrade of streetscaping along
arterials to allow for trees long term through
Capital Improvement programs including
installation of permanent irrigation systems
(example locations include 30th St, Iris Ave., and
Foothills Pkwy).
vi. Create green infrastructure master planning
document to improve stormwater management
vii. Review policies and enforcement for slacklining
pilot project utilizing trees in city parks.
C Start community dialog on appropriate updates
pertaining to trees on Private Property:
i. Convene a group of stakeholders to develop
regulations for any new requirements for tree
protection for private property trees. Determine
what level of protection is desired by the people
of Boulder.
ii. Benchmark codes from other communities
(i.e. prevent the removal of existing trees
prior to acquiring an approved landscape plan,
tree removal permitting process, preservation
requirements for certain private property trees,
require mitigation for significant, desirable
private trees removed through development
projects when replacements cannot be planted
on site, mitigation requirements, etc.)
iii. Review and strengthen parking lot shade
guidelines and enforcement.
• This could fall under a 2018 citywide ecosystem
management plan.
• Would it make sense for the Boulder Forestry
division to reside under Resilience /Sustainability
rather than Parks and Recreation?
• Other cities become accredited Tree Care
Industry Association- These associations perform
an audit every 3 years.
Goal 4. Streamline all forestry maintenance operations
and establish and increase funding and staff resources
to support desired community level of service for
urban forest management.
ACTIONS:
A Strengthen and streamline Forestry operations
maintenance processes and programs (includes
outreach, pruning, IPM, tree risk, commercial trees,
wood utilization, asset management, contracted
services and continued implementation of the EAB
Long Term Strategy.
B Establish a sustainable funding mechanism for
Boulder Forestry programs, including tree planting
and rotational pruning.
C Engage executive management in discussion and
collaboration regarding available/potential funding
options that support the community vision for
the urban forest and the desired level of service
expressed by stakeholders and community members.
D Bank mitigation fees for private trees removed
through site review projects (trees that cannot be
replaced on site must be mitigated with funds going
into the Tree Fund).Use funds to support new tree
WHAT DO WE WANT?112
ResponsibilityCity (tax$)50 10 15 20
Partnerships
Community
Timing
A
C D
B
planting, establishment, and maintenance, including
programs that increase trees on private property.
Some key comments that came out of the discussion for
goal no. 4 include:
• Citizens every two years have a funding requests-
we should be asking residents to fund certain
forestry efforts.
• Cultural Landscape Rehabilitation Funding
could be source to help with tree planting and
maintenance.
• Engage everyone, create lobby mechanism to get
message out and get it on ballot.
• Organize all “public trees” into common
management and establish funding mechanism
• A ballot initiative should be established to help
fund Action B. This is illustrated on the graph as
Action E .
Goal 5. Explore the establishment of a partner non-
profit urban forest foundation or “tree trust” to
leverage additional financial and community support
for the urban forest.
ACTIONS:
A Create a call to action to articulate “Why Now?”
B Facilitate the development of a leadership team to
direct the vision and capacity building of an emerging
nonprofit. Tap into existing networks, resources,
and populations (non-profits, businesses, NPO’s,
government agencies, school districts, neighborhood
associations).
C Develop specific and actionable goals and funding
sources. The city can initiate a program with seed
money and deliverables, but other fund-raising
efforts will be necessary to support continued
volunteer efforts. Explore grants for project funding
and to diversify funding sources and partners.
D Evaluate outreach strategies and divide outreach
between Boulder Forestry and urban forest
foundation regarding raised money, trees planted
and new memberships.
E Partner with private property owners to provide
cost-sharing, free replacement trees, or incentives
for private property tree planting. Note: This option
was not reflected on the graph, as the working
group participants couldn’t determine where this
action should be located and how this effort may be
executed.
Some key comments that came out of the discussion for
goal no. 5 include:
• We need to identify potential benefactors to kick
off a larger foundation.
• Corporate sponsorship.
• Create a tree trust committee to evaluate the
establishment of a foundation.
• PLAY Boulder Foundation (PLAY) wants to take on
the main arm of the foundation as the Tree Trust. ResponsibilityCity (tax$)50 10 15 20
Partnerships
Community
Timing
A
C
D
B E
The feedback collected from these three working group
sessions has helped to reevaluate and prioritize the actions
for specific goals for the UFSP. Additionally this information
will be used to help inform recommendations for a
marketing strategy, identifying strategic partners, tactics and
communication strategies.
WHAT DO WE WANT?113
Goal 6. Develop a community-led volunteer program
focused on urban tree canopy.
ACTIONS:
A Build a team of engaged advocates that understand
the community’s unique urban forestry challenges
and opportunities.
B Build a strong individual member base. Emulate
tactics from other local organizations that are
successful in advocating volunteers.
C Develop volunteer-led programs and train volunteers
to lead or assist with programs (may include:
forestry maintenance and general support such
as clearance pruning, pest surveys and reporting,
mulch distribution, managing online requests, youth
engagement/educational programs, educating
community, host a program to help subsidize the
cost of tree planting on private property, offering
block grants to subsidize private plantings and assist
neighborhoods in tree planting efforts, development
of an urban forest newsletter, etc.)
Goal 7. Continue existing and develop additional
youth engagement programs including educational
presentations, school tree plantings, opportunities
for input, etc.
ACTIONS:
A Continue partnership with Utilities to educate youth
about trees through city Water Festival.
B Collaborate with Boulder Valley School District (BVSD)
to develop urban forestry educational program for
elementary aged children and present annually.
C Continue seedling giveaway to Boulder Valley School
District 5th graders.
D Develop additional youth engagement programs.
The working group ran out of time before being able
to reflect their decisions for Q.6 and Q7 on the graph
presented.
Some key comments that came out of the discussion for
goal no. 6 and no. 7 include:
• Infilling Arborist careers, Arborists are recognized
as a skilled profession and therefore qualifies
for workforce development initiative- Front
Range apprenticeship program is currently
being designed to create a pipeline teaching
horticulture as career.
• Having the City of Boulder partner with local
schools to help educate kids and create
ambassadors.
• BVSD could partner with a non-profit for
educational programing.
• Need to start educating kids at an earlier age
• All about collaboration with all stakeholders.
Cooperative effort.
Who coordinates?
• Tree Museum- at CU-an existing resource that
could be utilized
for education.
In conclusion, the recurring themes that have emerged
from all three of the working group discussions include;
clear effective communication regarding the importance
of the urban forest and its’ effect on each individual
community members. The need for community
participation, and that the community’s desire for a
level of service and urban forest management they are
willing to allocate additional resources to.
Actions that identified the need for communication and
education were given immediate priority and were seen
as ongoing. This is evidenced in the charts for goals 1, 2
and 5 where all actions that include communicate and/
or educate resided on the timeline between 0-5 years.
Communication related actions were also prioritized as
mainly the responsibility of the city and included the
recommendation of hiring an outside marketing firm to
craft an effective and engaging message.
From the working group perspective education related
actions were seen as something that would be most
effectively executed by strategic partners. This is
consistent with past working group sessions in that
it focuses on cooperation with community partners,
sensing that strategic partners would likely be more
effective in soliciting community participation, through
their approach, ability to access various types of funding
and resources. In addition the group emphasized that
the urban forest is comprised of more than just public
trees, it is a community asset, and therefore, the
community envisions the need for a non-profit partner,
urban forest foundation or tree trust to help cultivate
and steer community involvement. During the final
meeting it was shared that Boulder PLAY would like to
become the foundation arm for a Tree Trust. Members
of the working group recommended that a committee
be established to provide some foundational framework
for a Tree Trust to successfully take hold.
WHAT DO WE WANT?114
effort to see if the students identified an element of
the plan they felt their peers would be interested in as
a topic for their 2017 Fall ATP.
John Marlin, a member of the Boulder Forestry division,
gave an overview of the plan, the role of Boulder Forestry
and impact of pests such as the emerald ash borer. As a
whole students were most interested in the large loss of
canopy due to emerald ash borer and how they could be
part of the solution. With this topic in mind the group
split into 4 smaller groups to discuss specific ideas on
what a future ATP project would entail. As a result a
semester long project will be co-developed with the
students, allowing them to take their creative ideas
and help educate the public around threats to Boulder’s
Urban canopy.
Young Children's
Tree Preferences
Boulder Forestry coordinated with Growing Up Boulder,
Boulder Journey School, and Boulder County Head Start
in an effort to collect insights and generate awareness
among young children. Growing Up Boulder is Boulder’s
child-and youth-friendly city initiative and is based out
of the Community Engagement Design and Research
Center at the University of Colorado Boulder; its mission
is to empower Boulder’s young people with opportunities
for inclusion, influence, and deliberation on local issues
that affect their lives.
Through a series of activities that included outdoor
exploration, discussion video and drawing, children
were able to express their preferences and expand their
understanding of trees in their natural environment.
Overall, the greatest amount of discussion in each
working group session continually focused on actions
that closely align with the goals and actions stated in
the ‘Engage’ section of UFSP Goals. This tells us that the
community is in agreement with the UFSP stated need
for the community to work alongside the department
in order to achieve goals outlined in the strategic plan.
YOAB
In an effort to encourage Boulder’s youth to become
more civically engaged, Boulder has established a Youth
Opportunities Advisory Board (YOAB). YOAB is a group
of 16 City of Boulder resident high school students, who
work to promote the youth voice in the community,
provide opportunities for youth across the city and advise
the municipal government on youth-related policies
and issues. In addition to monthly meetings, each year
students are involved in an Alternative Team Project,
(ATP). ATP’s are semester-long projects comprised of
3-4 students who select their own topics based on the
opportunities available and what is meaningful to them.
Boulder Forestry coordinated with YOAB to present the
Boulder Urban Forestry’s Strategic Plan process in an
ADDITIONAL THOUGHTS TO CONSIDER:
• Professional communication and marketing
• Care is more consequential than planting
• Tree give-away care supplement. e.g. 10 min
education pamphlet.
• Someone needs to be in charge of the education
and communication.
• Reexamine spring clean up for tree maintenance.
• Should Forestry be under Sustainability or
Resilience? ex. Recycling and Compost.
• Forestry is a citywide resource more than Boulder
Parks and Rec or Public Works.
• Support accreditation of private companies.
• Bond funding to support Forestry/EAB.
• Cultural landscape rehabilitation funding for
historic properties.
• Identify benefactors or corporate sponsors.
• Create a committee to direct the Tree Trust.
• Tree Trust vs. tree trust (general term.)
• Clarify tree fund in no. 4.
• Arboretum
• Include career development and training for youth
(Youth Engagement).
• Start earlier than 5th grade, eco-cycle partnership
for education.
• Champion tree list, highlight in the plan.
WHAT DO WE WANT?115
The following summarizes young children’s thoughts
about trees.
• Provide shade.
• Have berries, seed pods, and acorns to squish
and use for imaginative play.
• Encourage wildlife (squirrels and chipmunks).
• Are deciduous, so they can play in the leaves.
• Bear fruit, because they can eat the fruit and
climb these trees more easily.
The results of these activities were communicated
through a brief video and poster which was shared at
the public meeting.
Final Open House
The final draft of Urban Forest Strategic Plan (UFSP)
was presented to the Boulder community at Upslope
Brewing Company. This meeting provided a chronology
of the research, community outreach and milestones
that occurred throughout the process. Additionally this
meeting provided Boulder Forestry the opportunity to
present a comprehensive summary of the strategic goals
and actions that will take place in order to meet the
needs of Boulder’s urban forest as well as community
stated desires for the future of their urban forest.
Multiple stations featuring specific topics allowed
attendees to either learn individually or engage with
members of the forestry division. The stations focused
on sharing the goals and actions outlined within the
UFSP, providing continued education around EAB, GIS
mapping, data collection and introducing the partnership
with the PLAY and their initiative of creating a Tree
Trust. A core objective of the event was to clarify where
city’s Forestry’s efforts will be concentrated and clearly
communicate the level of community participation
needed in order to achieve collective goals.
The Goals and Actions boards showed goals across four
main categories: Plan, Protect, Manage and Engage.
In response to one of the actions within the Engage
category, Boulder forestry partnered with PLAY, one
of the featured stations at the event. PLAY has been
in the process of developing a Tree Trust, an initiative
designed to help assist with educating and engaging
community participation around Boulder’s urban forest.
Their station focused on introducing the Tree Trust
initiative to the community, recruiting volunteers and
gathering community preferences around priorities for
the Tree Trust over the next few years.
PLAY solicited feedback on activities related to each
UFSP goal category. Feedback from the community
revealed an overall preference for activities under the
categories of Protect and Manage. The specific activities
that received the most interest were: Fund tree plantings
and care program for private trees through a Tree Trust
membership model, and Digital mapping of private
trees through a neighborhood/HOA mapping program.
Community members also shared some of their own
ideas, which included a summer camp for kids involving
tree identification and care, educating neighborhoods
on tree care and initiating friends of the urban forest.
The event was well attended and participants were very
engaged and able to successfully field their questions with
members of the forestry division. The station focused
on GIS mapping tools had a number of participants
interested in finding out more about their own trees.
PLAY also had many lucrative conversations around the
Tree Trust, receiving 6 volunteer requests, two of which
committed to joining the Tree Trust committee and one
interested in spearheading a Friends of the Tree Trust
membership program focusing member retention at the
neighborhood level.
Conclusion
We can conclude from the engagement process that
the Boulder community values their urban forest,
understands impending threats and wants to see the
urban canopy thrive and grow.
We also know that the continued health and maintenance
of Boulder’s urban forest is a complex task that requires
WHAT DO WE WANT?116
priorities for the UFSP explore; the consolidation
of urban forestry responsibilities, increasing staff
resources and funding, providing a more consistent
contracting operating procedure, improvements to
the tree inventory database, further development and
integration of the IPM program, and periodic review and
alignment of UFSP priorities.
Protect
The urban forest represents a valuable asset, one which
must be nurtured and protected. This is accomplished
through municipal code, policies, and design and
construction standards that support tree planting and
longevity. The priorities of this goal include; revision of
tree protection codes and policies, improved standards
for tree maintenance, expanding options for tree
mitigation payback, streamlining pesticide permitting,
and improvements to the TSIP.
Engage
The Boulder community places a high value on
environmental stewardship. Engaging with and educating
the community with the most current information on the
urban forest will mobilize activists and facilitate policy
implementation. In the development of the UFSP, many
stakeholders expressed a desire for a community-based
urban forest advocacy group to promote, protect, and
enhance Boulder’s urban forest. Priorities to engage the
community are; communicating UFSP goals and plans,
diversifying funding sources and partners, facilitating
private property tree plantings and maintenance, and
the establishment of a partner non-profit urban forest
foundation.
resiliency and sustainability, preservation, tree planting
initiatives, food gardens, and solar solutions (Davey
Resource Group, 2017). The case studies offer insight
into strategies that were particularly effective, as well
as possible pitfalls to avoid. Lessons learned from these
programs were incorporated into the priorities and
actions of the UFSP.
Plan Goals and Priorities
Based upon review of the current urban forestry program
and resources,and input from the community and other
stakeholders, the UFSP identifies four goals.
Plan
Urban forestry is an important part of Boulder’s
resilience strategy. Increasing the resilience and
sustainability of the urban forest directly supports
the resilience of the community. The priorities of this
goal include; establishing a no-net-loss canopy goal,
developing a planting initiative that increases trees on
public and private property, increasing species diversity,
development of specific resiliency plans (climate,
emergency, drought, pests etc.), and integrating urban
forestry goals with other city guiding documents.
Manage
Boulder has an exceptional Forestry program and
already implements many industry BMPs. Management
joint efforts from the community and Boulder Forestry.
Though this process members of the Boulder community
have helped identify the core areas where assistance is
needed:
• Clear concise messaging around the benefits and
threats to Boulder’s urban forest.
• Broader, ongoing community wide education
focused on maintaining Boulder’s urban forest.
• Community participation in activities that best
support Boulder Forestry efforts.
The emerging partnership with PLAY is a strong first
step that has the potential to help with education
and community action. However, additional help
will be needed to support a citywide communication
effort that aligns with the strategic goals and actions
outlined in the UFSP and also effectively align with
efforts from strategic partners.
Davey Resource Group worked with Forestry to identify
successful programs throughout the U.S. in order
to explore best practices and potential solutions to
address the challenges and opportunities identified
by Boulder stakeholders. We explored the structure
and policies of more than 25 different programs and
interviewed program leaders to better understand the
key components that lead to success. DRG reviewed
focused on nonprofit tree advocacy, volunteers,
Conclusion
Case Studies
HOW DO WE GET THERE?117
The UFSP analysis provides a spatial understanding of
the past, present, and future potential for tree canopy,
and is a valuable tool to help managers align urban
forestry management with the community’s vision for
Boulder’s urban forest.
In Boulder, plantable areas include 4,335 acres, and
within that area, 905 acres are high or very high priority
planting areas. These high and very high priority planting
areas offer the highest return on investment.
Boulder Forestry will achieve this goal through smart
planning, effective management, tree protection
and community engagement. These four themes are
explored in the following pages.
The strategic plan includes three cost scenarios,
following the city’s business planning approach that
requires departments to prepare for a future without
increased revenue. This approach acknowledges the
need for an effective organization to balance priorities—
and their associated expenditures—using three tiers of
fiscal alternatives.
• The Fiscally Constrained ($) alternative plans for
prioritized spending within existing funding.
• The Action ($$) alternative describes the
additional services or capital improvement that
could be undertaken when additional funding is
available.
• The Vision ($$$) alternative represents the
complete set of services and facilities desired by
the community.
Goals, Priorities,
Actions
Given current losses to EAB and anticipated losses
to continued climate change stressors, Boulder
Forestry’s overarching 20-year goal will be to restore
and maintain, rather than increase, its current
canopy cover of 16%.
How Do We
Get There?
HOW DO WE GET THERE?118
Plan Manage Engage
• Develop and implement a 20-year Planting Plan for public trees to support the 16% urban tree canopy cover by 2037.
• Participate in an inter-departmental Urban Ecosystems Management Strategic planning process to integrate ecosystem protection and monitoring across urban, agricultural and wildland systems.
• Create an Urban Forest Emergency Response Plan for citywide coordination to ensure appropriate coverage and minimize risk to the public.
• Establish a dedicated, sustained funding source beyond the departmental budget for Boulder Forestry operations to increase the level of service to meet the community’s high standards.
• Expand the Public Tree Planting program to support efforts toward the goal of 16% canopy by 2037.
• Shift management responsibility for all trees in public street ROW and around public buildings under Boulder Forestry to maximize advantages in expertise and scale.
• Increase investment in proactive, preventative maintenance by exploring options to increase the frequency of pruning events for public street trees.
• Refine the Integrated Pest Management (IPM) Program to improve tree health while minimizing cost and negative impacts to ecosystems and the public.
• Streamline the Tree Safety Inspection Program (TSIP) to manage risk and minimize City exposure to claims as well as reduce the financial and logistical costs on forestry operations.
• Continue implementation of the EAB response strategy to maintain public safety, ecosystem services, and forest function in the face of unprecedented canopy loss.
• Transition to a common software Asset Management System to allow efficient forestry business processes across city work groups and provide essential baseline data for strategic forest management. • Continue to explore all wood utilization options to improve resiliency to increased cost or disappearance of any single waste stream. • Explore the expansion of the Commercial Tree Program (CTP) beyond the immediate downtown area to maintain urban tree canopy, protect property and better manage public safety issues.• Develop a staff succession plan within Forestry to encourage continual professional development and facilitate transitions in leadership to minimize disruption to operations.
• Deliver a State of the Urban Forest Report biennially for elected officials, key urban forest stakeholders, and the public.
• Provide the community with balanced and objective information to assist them in understanding the problems, alternatives and options to achieve the Boulder urban tree canopy goal.
• Partner with the community on projects to broaden knowledge, support and funding for the Boulder urban tree canopy goal.
• Develop and expand opportunities for community involvement in the commitment to achieve the Urban Tree Canopy goal.
• Involve the public on the analysis, alternatives and recommendations for further urban forestry related planning processes and potential code changes.
Protect
• Strengthen Boulder Forestry’s role in all city CIP projects to minimize damage to tree assets and canopy loss.
• Strengthen existing city requirements for trees on Public Property to increase tree protection, improve site preparation and strengthen tree species diversity requirements to maintain the urban tree canopy and increase forest resiliency.
• Strengthen existing and develop new city requirements for Private Property to increase tree protection, improve site preparation and strengthen tree species diversity requirements to maintain the urban tree canopy and increase forest resiliency. • Revise licensing requirements for all tree care companies performing tree work in Boulder to improve public safety and tree health.
PRIORITIES PRIORITIES
GOALS
HOW DO WE GET THERE?119
Urban forestry is an important part of Boulder’s resilience strategy. Resilience is the ability of a community to prepare for and respond effectively to stress.
Some stressors occur suddenly, like the 2013 flood, drought, and invasive pests. Others take their toll over time, including ever-increasing maintenance costs,
ongoing development pressure, and the senescence of large specimen trees. Whatever the stressor, what is most important is that resilient communities not
only bounce back from these challenges but also "bounce forward." These resilient communities preserve the quality of life today and improve their legacy for
future generations. Boulder’s urban forest serves as a buffer to many community stressors, providing cooling shade, cleaner air, and a reduction in stormwater
runoff to avoid sudden and more severe flooding. Increasing the resilience of the urban forest directly supports the resilience of the community.
The following priorities and actions support this goal:
PLAN
1. Develop and implement a 20-year Planting Plan for public trees to support the 16% urban tree
canopy cover by 2037.
a. Outline achievable canopy cover goals by maintenance district, accounting for current canopy level, land use, soils, irrigation, vulnerability
to heat islands and storm water, community desires and equity.
b. Determine ideal percentages for species diversity at every scale from block, to maintenance district to citywide.
c. Conduct urban tree canopy (UTC) analysis every ten (10) years to record changes and progress towards community canopy goals.
d. Conduct tree resource analysis every ten (10) years to record changes and progress towards planting and diversification goals.
e. Identify species that will be resilient to potentially drier, hotter conditions of Boulder’s future climate.
f. Identify baseline species diversity within maintenance districts, develop lists of desirable species for each maintenance district and
establish diversification goals per maintenance district. Prioritize large stature shade trees to maximize leaf area and ecosystem service
provision per tree.
g. Establish a specific number of plantings for each year through 2037. Prioritize tree planting within neighborhoods based on canopy
priorities. Focus tree planting where community need is greatest.
h. Ensure tree planting and diversification goals are included and prioritized within all city projects.
i. Future planting schedules will be adjusted to account for any season that falls short of its goal.
j. Develop process to monitor survival of new plantings and modify planting schedule to account for losses.
k. Develop process to comprehensively reassess canopy by maintenance district every ten years to determine if progress is proportional to
goals. This evaluation process should include revisiting planting plans if the program is not on track to meet 2037 goals.
Priorities and ActionsTimeframeCost
Year
1-5 $$
HOW DO WE GET THERE?120
2. Participate in an inter-departmental Urban Ecosystems Management Strategic planning process
to integrate ecosystem protection and monitor across urban, agricultural and wildland systems.
a. Participate in a consortium of environmental planners, activists, researchers, and organizations to develop an integrated ecosystems
management strategy that can address increasing environmental threats and build on opportunities to enhance ecosystems and ecosystem
services in and around the city.
b. Collaborate on the Plan with staff from multiple departments such as OSMP, Long Range Planning, Public Works, Utilities, etc.
3. Create an Urban Forest Emergency Response Plan for citywide coordination to ensure appropriate
coverage and minimize risk to the public.
a. The response plan should include branch clean-up efforts, wind/snow storms, floods, and planning for each stage of drought.
b. Using data from the 2002 drought and other dry periods, prioritize trees within city parks based upon species, size, contribution to the
site and overall value to the community to maintain adequate tree canopy.
c. Determine which areas of park landscapes should be irrigated to preserve highest priority trees based on drought severity and duration
and use appropriate amount and timing of irrigation for species preservation in line with water conservation goals.
d. Keep watering regimes during drought conditions in mind when designing future park irrigation systems.
e. Ensure adequate water for trees in median areas during periods of mild to moderate drought.
f. Work with the Utilities Division to establish temporary modified water budgets for parks during periods of drought and when establishing
new landscapes when original landscapes were impacted by natural hazard.
g. Clarify roles of city personnel for coordination, communication, pruning/removal of public trees, and debris cleanup management in the
event of wind or snow storms or other local natural disasters causing major damage to trees.
h. Develop criteria for appropriate levels of city inclusion into branch clean-up efforts based upon storm impacts; criteria may include:
Minor events - residents responsible for their own debris removal; Moderate events - limb drop-off services provided by the city; Major
events – citywide clean-up.
Priorities and Actions
Year
1-5 $
Year
6-10 $$
Timeframe Cost
HOW DO WE GET THERE?121
Boulder has an exceptional Forestry program and already implements many industry BMPs, from selecting quality nursery stock, to regular maintenance and
pruning, to the removal process when salvageable wood is utilized. Boulder’s 50,800 public trees are maintained and inspected regularly, with their history
and status tracked in a management database. Since 2013, the personnel, training, equipment, and budget to support these activities has not kept pace with
community expectations, leading to longer pruning cycles, increasing response times, and some deferred maintenance. Reasons for this include the steeply
increasing costs of contract pruning and traffic control plans and an unprecedented number of recent tree removals due to severe weather events and invasive
pests, including the EAB.
These management priorities, goals, and tactics provide guidance for steering Boulder’s advanced and proactive urban forest management program back in line
with the community vision for the urban forest.
The following priorities and actions support this goal:
MANAGE
1. Establish a dedicated, sustained funding source beyond the departmental budget for Boulder
Forestry operations to increase the level of service to meet the community’s high standards.
a. Engage executive management regarding potential funding options, such as voter-supported bonds to fund capital projects for improved
infrastructure and streetscaping along arterials and improved future maintenance.
b. Develop process to collect mitigation fees for private trees removed through development projects to increase tree planting and post-
planting care.
c. Identify the funding mechanism when new public trees are added through development.
d. Research the ability to use urban forest planting and/or preservation projects to earn carbon credits and create an additional funding
source.
e. Allocate funding to temporarily increase the annual tree planting budget for ten years to support urban tree canopy goal.
f. Anticipate budget changes due to living wage requirements for tree planting and maintenance contractors.
g. Identify options for short-term funding to manage emergency response for tree damage after storm events, including debris management.
Priorities and ActionsTimeframeCost
Year
1-10 $-$$$
HOW DO WE GET THERE?122
2. Expand the Public Tree Planting program to support efforts toward the goal of 16% canopy by 2037.
a. Develop a more strategic approach to species and site selection to ensure the resilience and optimize ecosystem service provision of
Boulder’s urban forest.
b. Conduct a cost-benefit analysis of contracted versus In-house plantings to maximize available resources.
c. Increase the number of trees planted on public property to support urban tree canopy goal.
d. Coordinate with other city departments to maximize the number of trees planted through CIP projects.
e. Collaborate with nurseries to propagate a more diverse palette of trees that tracks Boulder’s diversity requirements and updated planting
recommendations. Determine if nurseries may offer discounts for lower income families.
f. Continue collaboration with regional urban forest managers to explore opportunities for cost-sharing and bulk pricing for tree stock and/
or growing trees through multi-year contracts.
g. Experiment with new tree species to assess their performance in Boulder’s climate. Establish a pilot for different nursery stock to assess
potential inclusion in procurement/planting processes.
h. Develop a consistent methodology to monitor and track new planting survivability long-term.
i. Formalize and document planting program business processes with a focus on entering new trees into inventory and assigning early growth
stage maintenance at planting.
3. Shift management responsibility for all trees in public street ROW and around public buildings
under Boulder Forestry to maximize advantages in expertise and scale.
a. Collaborate with other city work groups to document current public tree assets and jurisdictions.
b. Calculate the cost maintaining existing trees outside of Boulder Forestry jurisdiction and identify potential funding sources for all
maintenance.
c. Initiate conversation between departments regarding consolidation of city owned trees under Boulder Forestry along with proportional
resources.
d. Collaborate with Public Works on protocol for clearance pruning, including training of Public Works staff and joint pruning operations.
e. Collaborate with flood utilities to develop proactive tree removal plan for ash trees infested with EAB along creek flood ways.
Priorities and Actions
$$
Timeframe Cost
$
Year
1-5
Year
6-10
HOW DO WE GET THERE?123
4. Increase investment in proactive, preventative maintenance by exploring options to increase
the frequency of pruning events for public street trees.
a. Maintain the current eight-year pruning rotation for city park trees to address structural defects in trees before time and growth make
them costly and hazardous.
b. Phase in the reduction of the systematic pruning rotation for street trees from the current 14 years to the industry recommended
eight years while expanding the number of size classes pruned. Evaluate progress annually to ensure program is moving towards the
eight-year goal.
c. Estimate cost/benefit of expanding pruning rotation to include Flatirons Golf Course.
d. Develop a process to standardize and assign follow-up work and structural prunes on young trees.
e. Annually revisit contract specifications and in-house policies and directives to ensure that tree care operations adhere to current
industry standards, including ANSI A300 Standards for Tree Care Operations, ANSI Z133.1-2012 for Arboricultural Operations Safety
Requirements, and ISA Series BMPs.
f. Ensure that all tree care operations comply with federal and state wildlife protection requirements. Forests in natural areas should be
managed as minimally as possible to preserve wildlife habitat, natural resource value, and creek integrity.
g. Strengthen contracting process to be more consistent: check all contracts for completion and consistency, coordinate with purchasing
office instead of directly through the city attorney’s office to streamline contracting process, develop continuing services agreements
in addition to our annual services agreements.
h. Streamline and coordinate traffic control to require tree care companies subcontract work, or allow tree care contractors to directly
invoice Forestry for needed traffic control.
i. Train park staff to provide young tree clearance pruning to reduce demand for clearance pruning in parks.
j. Explore cost/benefit and funding mechanisms for establishing a second in-house crew.
Priorities and ActionsTimeframeCost
$$-$$$Year
1-5
HOW DO WE GET THERE?124
5. Refine the Integrated Pest Management (IPM) Program to improve tree health while minimizing
cost and negative impacts to ecosystems and the public.
a. Ensure BMPs are followed for the maintenance of all diseased/infested trees for both public and private property.
b. Continually read current scientific literature, attend conferences, consult with researchers, and meet with vendors to identify new
solutions to pest problems.
c. Annually review and update specifications for applicators.
d. Establish pilot program to conduct select injection treatments in-house to reduce contracted cost and increase logistical flexibility.
e. Develop a pesticide permitting process for private treatment of public street trees with the notification requirement on the applicator
rather than the property owner.
f. Evaluate public requests to apply pesticides to public street trees to ensure application will not conflict with city policy or unacceptably
impact human health or ecological function.
6. Streamline the Tree Safety Inspection Program (TSIP) to manage risk and minimize City exposure
to claims as well as reduce the financial and logistical costs on forestry operations.
a. Ensure that forestry staff are Tree Risk qualified through the International Society of Arboriculture and that risk assessments are
conducted by qualified arborists.
b. Document TSIP processes to facilitate its transition to Beehive. Explore whether tree risk can be managed through other existing
programs and workflows after Beehive transition.
c. Reduce size of program by streamlining hazard surveys and developing specific, stringent guidelines for trees to be included in program
and a process for removing trees from program when risk is mitigated through pruning or target relocation.
d. Develop guidelines for using different classes of inspection that are proportional to likely tree risk and reasonable given the size of
the resource.
e. Shift to industry recommendations for inspection of hardware (cables/bracing) in public trees.
$
$
Priorities and ActionsTimeframeCost
Year
1-5
Year
1-5
HOW DO WE GET THERE?125
7. Continue implementation of the EAB response strategy to maintain public safety, ecosystem
services, and forest function in the face of unprecedented canopy loss.
a. Continue to partner with Colorado EAB Response team on EAB management including biocontrol releases.
b. Increase the diversity of tree species on public property and induce or incentivize planting on private property and through development.
c. Evaluate public ash scheduled for treatment annually and ensure trees still meet criteria for treatment.
d. Continue to proactively remove ash before they present an unacceptable risk to the public or overwhelm staff management capacity.
e. Strengthen and continue collaboration with other departments to assist with private tree enforcement.
f. Increase the timeframes for compliance with enforcement of private property tree removals to allow for local contractors’ scheduling
concerns, and send “pre-notices” for property owners so they have more time to react before trees become higher risk.
g. Control invasive plants by collaborating with other departments on the re-vegetation of existing natural areas.
h. Train Public Works staff to monitor trees along bike paths under Public Works jurisdiction for public safety.
8. Transition to a common software Asset Management System to allow efficient forestry business
processes across city work groups and provide essential baseline data for strategic forest
management.
a. Document data management processes for transition to Beehive.
b. Conduct staff trainings to ensure business process implementation for Beehive.
c. Develop, adopt and execute uniform work flows for asset management software across City work groups programs.
d. Adhere to uniform business processes for data entry and management to ensure the tree inventory remains up-to-date, accurate,
functional across work groups, and resilient to employee turnover.
e. Ensure all private pesticide applications to public trees are entered into the Forestry Asset Management System.
f. Develop protocol for documenting and protecting habitat of protected species on Forestry assets during Beehive transition.
g. Streamline the integration of information collected from the Citizen Science 100 Resilient Cities program into city databases.
h. Conduct a resource analysis every ten years, including population, structure, replacement value, and tree services.
i. Conduct a canopy analysis every ten years, including land cover, ecosystem services, changes over time, and land use.
Priorities and ActionsTimeframeCost
$$Ongoing
$Year
1-5
HOW DO WE GET THERE?126
9. Continue to explore all wood utilization options to improve resiliency to increased cost or
disappearance of any single waste stream.
a. Continue to divert all wood resources away from the landfill.
b. Develop distribution processes for all wood resources and document the annual amount of wood re-purposed and its end-use.
c. Continually evaluate new end-uses for urban wood waste and process improvements for woodlot.
10. Explore the expansion of the Commercial Tree Program (CTP) beyond the immediate downtown
area to maintain urban tree canopy, protect property and better manage public safety issues.
a. Analyze inventory data and determine cost to expand program focusing on higher priority areas such as those with less canopy coverage.
b. Coordinate with Community Planning and Sustainability to ensure all landscaping requirements for both public and private property are
met and enforced.
c. Build a database of commercial properties with potential planting sites and owner contact information to assist with future outreach
efforts.
11. Develop a staff succession plan within Forestry to encourage continual professional development
and facilitate transitions in leadership to minimize disruption to operations.
a. Formalize policies to develop personnel capable of assuming leadership positions.
b. Identify minimum educational and certification requirements for supervisory positions and make time and resources available to junior
staff to pursue those qualifications.
c. Encourage and accommodate employee participation in trainings, particularly supervisory trainings.
d. Conduct regular staff trainings on asset management software, young tree structural pruning, and emerging urban forest challenges and
opportunities.
12. Deliver a State of the Urban Forest Report biennially for elected officials, key urban forest
stakeholders, and the public.
a. Include updated benchmark numbers for trees planted, removed, pruned, and changes to the overall community urban forest.
b. Integrate into Annual Plan reviews.
Year
6-10 $$
Priorities and ActionsTimeframeCost
Ongoing $
$Year
1-5
Ongoing $
HOW DO WE GET THERE?127
The urban forest represents a valuable asset, one which must be nurtured and protected. One of the key directions from the stakeholder interviews and
community meetings was a directive to maintain and preserve existing trees. This is accomplished through municipal code, policies, and design and construction
standards that support tree planting and longevity. In most cases, these code revisions are small adjustments to sound existing policies.
The following priorities and actions support this goal:
PROTECT
1. Strengthen Boulder Forestry’s role in all city CIP projects to minimize damage to tree assets
and canopy loss.
a. Emphasize public trees as essential infrastructure and the need to preserve individual trees and maintain urban tree canopy in light
of climate change.
b. Prioritize the upgrade of streetscaping along arterials to allow for trees long-term through Capital Improvement projects, including
installation of water-efficient, permanent irrigation systems (example locations include 30th St, Iris Ave.).
c. Participate in the development of Park Design and Construction Standards, processes, and contract templates.
d. Collaborate with CIP project teams to identify best way to formalize Forestry participation in the planning process to identify potential
impacts on trees and advise on alternative or mitigative approaches.
e. Formalize Forestry participation during construction so that impacts to trees can be monitored and minimized.
f. Formalize Forestry participation post-construction to ensure follow-up care on newly planted trees and enforce warranty replacements.
g. Increase the planting of large maturing, drought tolerant species on all public projects requiring improved tree diversity.
h. Require mitigation for significant, desirable public trees removed through CIP projects when equal public replacements cannot be
planted on-site. Provide multiple options for mitigation calculations rather than only appraised value to ensure equitable calculations
and minimize staff time.
i. Require adequate planting space (soil volume) for all new tree plantings based on industry BMPs. Integrate structural cells whenever
possible, and as funding allows, in commercial areas for all projects.
j. Require, through code, all new plantings have a water efficient, permanent irrigation system maintained for the life of the tree.
k. Explore hiring temporary forestry inspectors for bond-related parks and transportation CIP projects involving trees.
l. Review policies and enforcement for slacklining pilot project utilizing trees in city parks.
$$-$$$
Priorities and ActionsTimeframeCost
Year
1-5
HOW DO WE GET THERE?128
2. Strengthen existing city requirements for trees on Public Property to increase tree protection,
improve site preparation, and strengthen tree species diversity requirements to maintain the
urban tree canopy and increase forest resiliency.
a. Review and update current ordinances and the city Design and Construction Standards to reduce ambiguity in tree protection standards,
increase requirements for tree planting and diversity, emphasize location of new trees for urban heat island mitigation, and develop
guidelines for tree management and planting to accommodate both a growing urban tree canopy and solar panels.
b. Review approved public tree planting list biennially to add or replace species based on performance or new information. Maintain
species list as a separate document from code or standards to streamline updates.
c. Require adequate planting space (soil volume) for all new tree plantings based on industry BMPs. Integrate structural cells with
stormwater inlet option whenever possible in commercial areas for all projects. Consider permaculture concepts to build soil nutrition
and capture rainwater.
d. Improve stormwater management with green infrastructure on public property through private development, including minimum
green infrastructure requirements for new and redeveloped sites.
e. Require all new plantings have a water efficient, permanent irrigation system maintained for the life of the tree. Enforce existing
requirements for irrigation and mulching for public street trees by adjacent property owners.
f. Formalize consequences for unpermitted pesticide applications to public trees. Update code to address enforcement and penalties.
$
Priorities and ActionsTimeframeCost
Year
1-5
HOW DO WE GET THERE?129
3. Strengthen existing and develop new city requirements for Private Property to increase tree
protection, improve site preparation, and strengthen tree species diversity requirements to
maintain the urban tree canopy and increase forest resiliency.
a. Benchmark tree protection and diversity requirements for other cities as a comparison.
b. Develop five-year public engagement plan for city code, city manager rule, policy, and guideline updates. Update codes to align with
the community vision for tree protection and mitigation for private property trees and phase in gradually over a specified period of
time.
c. Update tree protection requirements in city codes and City of Boulder Design and Construction Standards and related permitting
processes to protect and prevent the removal of existing trees prior to acquiring an approved landscape plan.
d. Require mitigation for significant, desirable private trees removed through development projects when replacements cannot be
planted on-site. Provide multiple options for mitigation calculations rather than only appraised value to reduce staff time needed.
e. Update codes to improve, inspect and enforce long-term maintenance of landscape requirements on private property.
f. Add personnel necessary to oversee and monitor tree protection during construction on private property.
g. Require adequate planting space (soil volume) for all new tree plantings based on industry BMPs. Integrate structural cells with
stormwater inlet option whenever possible in commercial areas for all projects. Consider permaculture concepts to build soil
nutrition and capture rainwater.
h. Improve stormwater management with green infrastructure on private property through private development, including minimum
green infrastructure requirements for new and redeveloped sites.
i. Review parking lot shade guidelines and enforcement. Strengthen policies to provide increased shade within a 20-year establishment
period.
j. Update codes to add appeals process for enforcement of tree nuisance abatement on private property and lengthen the timeframe
for remedy to timeframe appropriate for tree and site conditions.
$$
Priorities and ActionsTimeframeCost
Year
6-10
HOW DO WE GET THERE?130
4. Revise licensing requirements for all tree care companies performing tree work in Boulder to improve
public safety and tree health.
a. Explore requirement for all licensed tree contractors to obtain the ISA certified arborist certification and provide proof of formal safety training
by licensees.
b. Use meetings, newsletters, and trainings to increase contact with licensees, strengthen the high-quality of tree care, and ensure knowledge
of pertinent city codes.
c. Continue to increase accessibility of licensing process and website to accommodate different languages and disabilities.
d. Formalize protocol for responding to wildlife in trees during pruning or removal operations for both city staff and contractors.
e. Develop protocol for response by contractors when conflict with protected animal species cannot be avoided.
f. Develop enforcement mechanism to ensure company compliance with all licensing requirements, city codes and natural resource protection
requirements.
$
Priorities and ActionsTimeframeCost
Year
1-5
HOW DO WE GET THERE?131
The Boulder community places a high value on environmental stewardship. In the development of the UFSP, many stakeholders expressed a desire for a
community-based urban forest advocacy group to support environmental stewardship and promote, protect, and enhance Boulder’s urban forest. Connecting
with and educating the community with the most current information on the urban forest will mobilize activists and facilitate policy implementation. Specific
priorities include; opportunities to establish and promote a deeper understanding of the year-round benefits of trees, challenges and opportunities facing the
urban forest, opportunities for volunteers and collaboration, updates to the Forestry website, the development of specific outreach materials for new plan
components (e.g., drought, landscaping, EAB), and print material outreach such as updated door hangers.
Priorities to engage the community are; communicating UFSP goals and plans, diversifying funding sources and partners, facilitating private property tree
plantings and maintenance, establishing a partner non-profit urban forest foundation and using the forestry website, flyers, tabling events, tree talks, and
social messaging to connect with the Boulder community.
The following priorities and actions support this goal:
ENGAGE
1. Provide the community with balanced and objective information to assist them in understanding
the problems, alternatives, and options to achieve the Boulder urban tree canopy goal.
a. Formalize clear and consistent design and language for Boulder Forestry outreach materials.
i. Hire a professional firm to develop and execute a consistent outreach strategy outside of the capacity of the department.
ii. Coordinate the outreach strategy as citywide rather than a departmental effort.
iii. Communicate no-net-loss goal to the community and engage them in identifying and executing solutions. Create a call to action and
clearly articulate “Why Now?”
iv. Share and promote Boulder Forestry's vision, capabilities, and expertise to increase public support and willingness to fund and expand
Boulder Forestry’s role.
v. Encourage community members to act in urgency to the predicted decline of the urban tree canopy.
a. Systematically contact commercial property owners list directly and via DBI/DMC newsletters to engage with tree maintenance
activities such as watering, replacing mulch, etc. to maintain tree health.
vi. Promote public tree planting plan for the community to support the Urban Tree Canopy goal including; prioritized areas, diversification
goals, and maintenance guidelines.
vii. Promote drought preparedness messaging to the community to minimize loss and/or damage including; basic steps to conserve water
$
Priorities and ActionsTimeframeCost
Year
1-5
HOW DO WE GET THERE?132
while preserving trees, when and how much to irrigate trees, how to conduct simple inspections of their irrigation system, and identify
over watering and advantages of drought tolerant trees compared to low water use trees.
viii. Promote the public tree EAB response plan for the community to provide the available community actions to respond constructively to
the anticipated impact.
a. Increase public outreach and notification so residents are aware of full scope of EAB impact and urgency and what they can do to
support and sustain the urban canopy.
b. Develop outreach campaign for applicators and residents to increase awareness and compliance with pesticide permitting process.
c. Promote timely removal and replacement of dead/dying ash trees on private property for safety.
d. Develop sign designs and a plan for ash tree removals in high traffic areas, like the Boulder Creek Path for education and awareness
for community members and visitors.
e. Inform public of vetted resources available, such as the planting plan, for replacement options to support canopy goals and public
safety.
ix. Promote individual forestry programs and respective strategies, especially sensitive programs such as Integrated Pest Management.
x. Update Boulder Forestry notification door hangers;
a. Evaluate the tree removal notification process to ensure residents understand the timeline and reasons for specific tree removals.
b. Develop educational door hangers (i.e. cartoon of thirsty tree to get residents to water routinely).
c. Develop door hangers to explain why some trees must be treated with pesticides.
b. Continue to update and improve the Boulder Forestry website.
i. Increase user access to key information and resources.
ii. Publicize current canopy characteristics such as population size, diversity, and ecosystem services compared to 2037 goals.
iii. Maintain a public-facing tree inventory platform for resident information, requests. This platform can also serve as a place to calculate
and publicize ecosystem services.
iv. Add a dynamic map of contracted work and rotational pruning schedules.
v. Provide easy access to or integrate licensing and permitting process workflows.
vi. Highlight interesting and fun apps and tools already available, such as the Notable Tree List and public tree identification.
vii. Develop a digital platform for people to build community through shared passion for trees and the natural environment.
Priorities and ActionsTimeframeCost
HOW DO WE GET THERE?133
viii. Educate the public about why and which pesticides are used.
ix. Provide transparent budget and cost information for all policy actions.
x. Create a system for public suggestions for process improvement ideas.
c. Continue existing youth educational programs.
i. Continue partnership with city utilities to educate youth about trees through the Water Festival.
ii. Continue seedling giveaway to Boulder Valley School District elementary students.
d. Collaborate with private tree care companies to disseminate outreach materials and educate residents on behalf of Boulder.
e. Increase the use of social media (e.g., Facebook, Twitter) to better communicate with residents to build advocacy.
2. Partner with the community on projects to broaden knowledge, support and funding for the
Boulder urban tree canopy goal.
a. Support the development of a non-profit urban forest foundation or tree trust to support canopy goals and management.
i. Facilitate the development of a staff leadership team to direct the vision and capacity building of the emerging non-profit.
ii. Define the level of resources, staff, and funding that the department will allocate to a non-profit partner.
iii. Define success criteria for continued support of a non-profit.
iv. Identify and develop strategies with partners to solve community challenges through trees, for example: jobs training for youth.
v. Explore partnerships that can identify and support opportunities for grants, diversified funding, new partnerships, crowd-funding, etc
f. Continue to work with partners to expand waste utilization strategies to accommodate anticipated increase in debris.
i. Develop new or expand existing wood product markets for wood utilization.
ii. Communicate opportunities to end-users of wood to maximize re-use.
c. Identify and develop strategies with partners to remove barriers to volunteer participation for all community members, such as webinars
to aid with time challenges.
Priorities and ActionsTimeframeCost
$Year
1-5
HOW DO WE GET THERE?134
3. Develop and expand opportunities for community involvement in the commitment to achieve the
Urban Tree Canopy goal.
a. Continue to engage neighborhoods with volunteer tree planting events. Prioritize those areas with lower urban tree canopy or those
greatly impacted by EAB.
b. Identify and partner with vendors or sponsors to defray planting and ash removals costs for private property owners.
i. Continue to facilitate and/or subsidize tree planting for private property owners through existing tree-giveaways and sales.
ii. Explore partnerships that can identify and support opportunities for grants and financial assistance for low-income residents and non-
profits to facilitate tree removal and planting or help defray costs.
iii. Provide cost-sharing, free replacement trees, or incentives for private property tree planting.
iv. Explore options for grants and financial assistance or a payback program for low income residents or non-profits to facilitate tree
removal costs.
v. Offer mini-grants to subsidize private plantings and assist neighborhoods in tree planting efforts.
vi. Work strategically with other Boulder Forestry programs to source high-quality, diverse, low cost nursery stock. Tree requests are
made online and distributed at neighborhood events to facilitate easy transport.
vii. Provide information on proper tree planting and free mulch at tree giveaways/sales.
viii. Develop strategies to remove barriers to participation for all community members.
ix. Ensure tree planting programs are championed by an NGO or community leader to provide an alternative and effective voice in
communicating the critical nature of the current situation.
c. Recruit and train committed volunteers.
i. Assist with forestry maintenance activities and general support.
ii. Emulate tactics from local other local organizations that are successful in activating volunteers.
iii. Educate engaged advocates that understand the community’s unique urban forestry challenges, opportunities, policies, and funding
sources.
iv. Develop and implement additional youth engagement opportunities.
a. Develop additional opportunities such as photo contests, apps, interactive websites, etc.
b. Coordinate with BVSD on an environmental educational program for elementary-aged children.
c. Develop an arborist/green industry job training program for youth.
Priorities and ActionsTimeframeCost
$$Year
1-10
HOW DO WE GET THERE?135
v. Develop a community urban forestry newsletter collaboration between Boulder Forestry staff and volunteers.
vi. Provide opportunities for volunteers to take on leadership roles. Trainees become advocates for the urban forest, armed with knowledge
of area trees, policies, and threats.
d. Perform community satisfaction measurements and track participation in outreach events.
i. Create and deliver biannual surveys for urban forest stakeholders to ensure that management strategies continue to be aligned with
the community’s vision for the urban forest.
ii. Conduct annual UFSP reviews; update available resources, opportunities, and changes in community expectations.
4. Involve the public on the analysis, alternatives, and recommendations for further urban forestry
related planning processes and potential code changes.
a. Provide multiple opportunities for input from the public on Boulder Forestry Emergency Response Plan and Urban Ecosystems Management
Plan.
b. Work with an outside consultant to develop a five-year public engagement plan for City code, city manager rule, policy, process and
guideline updates pertaining to both public and private property trees.
c. Convene a group of stakeholders to review benchmarks and develop options and recommendations.
d. Hold community listening sessions to gauge public support for input on updates to City codes and policies.
e. Provide multiple opportunities for feedback; require a clear and transparent process with the community.
$
Priorities and ActionsTimeframeCost
Year
1-5
HOW DO WE GET THERE?136
HOW ARE WE DOING?137
The UFSP is a living document and city staff must
identify timeframes for reviewing accomplishments and
updating targets dates for action items.
Annual Plan Review and Update
The UFSP is an active tool that will guide management
and planning decisions over the next 20 years. The
goals, priorities, and actions will be reviewed yearly for
progress and integration into annual work plans. The
UFSP presents a long-range vision with timeframes that
are intended to be flexible. This will allow management
to adapt in response to emerging opportunities, available
resources, and changes in community expectations.
Each year, specific areas of focus should be identified,
which will inform budget and time requirements for
urban forest managers.
Resource Analysis
Boulder urban forest managers can update the tree
resource analysis over time and in conjunction with
inventory database updates. The structure, replacement
value, and tree services were initially quantified in
2015. Future studies can compare changes against these
benchmarks. This allows for the evaluation of changes
in tree condition, species diversity, services, and overall
resource value. A recommended action of the UFSP is
to complete this analysis every ten years to illustrate
progress and success towards UFSP goals.
Canopy Analysis
Canopy changes can occur gradually or suddenly. Using
GIS analysis, managers can measure and illustrate
changes in overall land cover as well as by neighborhood
and land-use. This information can be used to inform
canopy goals and monitor attainment. A canopy study
should be conducted every ten years, or after major
canopy-impacting events as needed.
State of the Urban Forest Report
This report, delivered to elected officials and key urban
forest stakeholders every two years, includes numbers of
trees planted and removed, and changes to the overall
community urban forest (e.g., structure, services,
and value). It will serve as a performance report to
stakeholders, and as an opportunity for engagement. The
data will be used to highlight the successful attainment
of UFSP priorities as well as to inform stakeholders
about any issues or stumbling blocks. This information
can be integrated into urban forest managers’ Annual
Plan Reviews and be used to pursue additional project
support and funding.
Community Satisfaction
The results of the UFSP will include measurable
improvements to efficiency and reductions in
maintenance costs. Over time, Boulder will need to
prepare people for bigger and longer-term benefits.
Achievement of UFSP goals will affect several positive
changes. These changes will support better tree health
and greater longevity, and also help prevent tree
failures. Meeting community expectations for the care
and preservation of the urban forest resource is an
important measure of success. Community satisfaction
can be measured through surveys, community meetings,
and public support for the UFSP. Community satisfaction
can also be reflected by the level of engagement and
support for urban forest programs. A periodic survey of
urban forest stakeholders will help managers ensure
that management strategies continue to be aligned with
the community’s vision for the urban forest.
Monitoring and
Measuring Results
How Are We
Doing?
HOW ARE WE DOING?138
APPENDIX139
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bouldercolorado.gov/wildlife/urban-wildlife-management-plan
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APPENDIX143
This section will discuss and define the methodologies
used for specific calculation referenced in the Plan:
i-Tree Canopy
Air Quality
The i-Tree Canopy v6.1 Model was used to quantify
the value of ecosystem services for air quality. i-Tree
Canopy was designed to give users the ability to
estimate tree canopy and other land cover types within
any selected geography. The model uses the estimated
canopy percentage and reports air pollutant removal
rates and monetary values for carbon monoxide (CO),
nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2),
and particulate matter (PM) (Hirabayashi 2014).
Within the i-Tree Canopy application, the U.S. EPA’s
BenMAP Model estimates the incidence of adverse health
effects and monetary values resulting from changes in
air pollutants (Hirabayashi 2014; US EPA 2012). Different
pollutant removal values were used for urban and rural
areas. In i-Tree Canopy, the air pollutant amount annually
removed by trees and the associated monetary value
can be calculated with tree cover in areas of interest
using BenMAP multipliers for each county in the United
States.
To calculate ecosystem services for the study area,
canopy percentage metrics from Urban Tree Canopy
land cover data performed during the assessment were
information about the model, please consult the i-Tree
Hydro v5.0 manual (http://www.itreetools.org).
To calculate ecosystem services for the study area, land
cover percentages derived for the project area and all
municipalities that were included in the project area
were used as inputs into the model. Precipitation data
from 2005-2012 was modeled within the i-Tree Hydro
to best represent the average conditions over an eight
year time period. Model simulations were run under a
Base Case as well as an Alternate Case. The Alternative
Case set tree canopy equal to 0 percent and assumed
that impervious and vegetation cover would increase
based on the removal of tree canopy. Impervious surface
was increased 0.8 percent based on a percentage of the
amount of impervious surface under tree canopy and
the rest was added to the vegetation cover class. This
process was completed to assess the runoff reduction
volume associated with tree canopy since i-Tree Hydro
does not directly report the volume of runoff reduced
by tree canopy. The volume (in cubic meters) was
converted to gallons to retrieve the overall volume of
runoff avoided by having the current tree canopy.
Through model simulation, it was determined that tree
canopy decreases the runoff volume in the project area
by 15,001,357 gallons per year using precipitation data
from 2005-2012. This equates to approximately 5,408
gallons per acre of tree canopy (15,001,357 gals/2,774
acres).
To place a monetary value on stormwater reduction,
the cost to treat a gallon of storm/waste water was
given by the local partners. This value was $0.0118 per
gallon. Tree canopy was estimated to contribute roughly
$177,016 to avoid runoff annually to the project area.
transferred to i-Tree Canopy. Those canopy percentages
were matched by placing random points within the
i-Tree Canopy application. Benefit values were reported
for each of the five listed air pollutants.
Carbon Storage and Sequestration
The i-Tree Canopy v6.1 Model was used to quantify the
value of ecosystem services for carbon storage and
sequestration. i-Tree Canopy was designed to give users
the ability to estimate tree canopy and other land cover
types within any selected geography. The model uses
the estimated canopy percentage and reports carbon
storage and sequestration rates and monetary values.
Methods on deriving storage and sequestration were
drawn from academic research (Nowak et al. 2013).
To calculate ecosystem services for the study area,
canopy percentage metrics from Urban Tree Canopy
land cover data performed during the assessment were
transferred to i-Tree Canopy. Those canopy percentages
were matched by placing random points within the
i-Tree Canopy application. Benefit values were reported
for carbon storage and sequestration.
i-Tree Hydro
The i-Tree Hydro v5.0 Model was used to quantify the
value of ecosystem services for stormwater runoff.
i-Tree Hydro was designed for users interested in
analysis of vegetation and impervious cover effects on
urban hydrology.
This most recent version (v5.0) allows users to report
hydrological data on the city level rather than just a
watershed scale giving users more flexibility. For more
Methodology
APPENDIX 144
APPENDIX145
2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2033 2038 NOTES
Rotational Pruning
Recommendation is to move to 8-year rotation for all trees.
A phased approach is preferred: Move from 14-year to 10-year for trees > 9” DBH, then
down to 8-year rotation for trees > 9” DBH then eventually 8 years for all trees.
Phase 1 - move from 15 year to 10 year rotation for public trees >9" DBH NA $55,000 $56,650 $58,350 $60,100 $61,903 $63,760 $65,673 $67,643 $69,672 $80,769 $93,634
Phase 2 - move from 10 year to 8 year rotation for public trees >9" DBH NA NA NA $50,000 $51,500 $53,045 $54,636 $56,275 $57,964 $59,703 $69,212 $80,235
Phase 3 - 8 year prune rotation for all public trees NA NA NA NA NA NA $78,000 $80,340 $82,750 $85,233 $98,808 $114,546
Subtotal $0 $55,000 $56,650 $108,350 $111,600 $114,948 $196,396 $202,288 $208,357 $214,608 $248,789 $288,415
Removals (Non-Ash)Average # non-ash tree removals is expected to increase due to senescence /public safety
concerns for silver maples and impacts due to climate change
Phase 1 - Add'l 50 tree removals/year $30,250 $31,158 $32,092 $33,055 $34,047 $35,068 $36,120 $37,204 $38,320 $39,469 $45,756 $53,044
Phase 2 - Add'l 100 tree removals/year NA NA NA $60,500 $62,315 $64,184 $66,110 $68,093 $70,136 $72,240 $83,746 $97,085
Phase 3 - Add'l 100 tree removals/year NA NA NA NA NA NA $60,500 $62,315 $64,184 $66,110 $76,640 $88,846
Subtotal $30,250 $31,158 $32,092 $93,555 $96,362 $99,252 $162,730 $167,612 $172,640 $177,820 $206,142 $238,975
Traffic Control and Towing Traffic control and towing costs are not currently budgeted and must come out of pruning
and removal budgets; funding request based upon average from past 5 years.
Current level of service unfunded $22,500 $23,175 $23,870 $24,586 $25,324 $26,084 $26,866 $27,672 $28,502 $29,357 $34,033 $35,054
Phase 1 - increases due to higher # prunes/removals NA $11,250 $11,588 $11,935 $12,293 $12,662 $13,042 $13,433 $13,836 $14,251 $16,521 $17,017
Phase 2 - increases due to higher # prunes/removals NA NA NA $8,500 $8,755 $9,018 $9,288 $9,567 $9,854 $10,149 $11,766 $12,119
Phase 3 - increases due to higher # prunes/removals NA NA NA NA NA NA $40,000 $41,200 $42,436 $43,709 $50,671 $52,191
Subtotal $22,500 $34,425 $35,458 $45,021 $46,372 $47,763 $89,196 $91,872 $94,628 $97,467 $112,991 $116,381
Tree Planting - Facilitate / Subsidize for Private Property
Recommendation is to facilitate and subsidize a private tree planting initiative for20 years
using same guidelines as 2018 Boulder Tree Sale. Phased approach from 150 to 350
trees/year, 500 trees/year then 750 trees/year. Subsidy is $20/tree. Cost could be reduced
if subsidy is via private donations. Subsidy not adjusted for inflation.
Phase 1 - subsidy for 350 trees $7,000 $7,000 $7,000 $7,000 $7,000 $7,000 $7,000 $7,000 $7,000 $7,000 $7,000 $7,000
Phase 2 - subsidy for 500 trees NA NA NA $3,000 $3,000 $3,000 $3,000 $3,000 $3,000 $3,000 $3,000 $3,000
Phase 3 - subsidy for 750 trees NA NA NA NA NA NA $5,000 $5,000 $5,000 $5,000 $5,000 $5,000
Subtotal $7,000 $7,000 $7,000 $10,000 $10,000 $10,000 $15,000 $15,000 $15,000 $15,000 $15,000 $15,000
Staffing
Phase 1 NA NA NA NA NA NA NA NA NA NA NA NA
Phase 2 - coincides with pruning /removal increases NA NA NA $70,000 $72,100 $74,263 $76,491 $78,786 $81,149 $83,584 $96,896 $99,803
Phase 3 - coincides with pruning /removal increases NA NA NA NA NA NA $70,000 $72,100 $74,263 $76,491 $88,674 $91,334
Subtotal $0 $0 $0 $70,000 $72,100 $74,263 $146,491 $150,886 $155,412 $160,075 $185,570 $191,137
TOTAL - Additional Funding Needed $59,750 $127,583 $131,200 $326,926 $336,434 $346,227 $609,814 $627,658 $646,038 $664,969 $768,492 $849,908
ADDITIONAL FUNDING NEEDED EACH YEAR TO ACHIEVE UFSP GOALS (includes annual 3% increase for inflation)
Funding
APPENDIX 146
Emerald Ash Borer - Parks & Recreation CIP Funding
2014 (from
Forestry Ops
Budget)
2015 (actual)2016 (actual)2017 (actual)2018
(estimated)
2019
(estimated)
2020
(estimated)
2021
(estimated)
2022
(estimated)
2023
(estimated)
2024
(estimated)
2025
(estimated)
2026
(estimated)
2027
(estimated)
2028
(estimated)NOTES
Tree Planting
Planned
prior to EAB
detection
$100,000 $73,385 $40,683 $72,833 $140,000 $140,000 $140,000 $140,000 $140,000 $140,000 $140,000 $140,000 $140,000 $140,000
Assumes 600 trees planted / year starting in 2019; planting
funding from multiple sources including EAB CIP, Forestry Ops
and Mitigation
Pesticide Apps $25,406 $56,000 $45,504 $23,226 $50,876 $45,000 $25,000 $45,000 $45,000 $25,000 $45,000 $45,000 $25,000 $45,000 $45,000 Treating 1339 public ash trees on 3-year rotation with Tree-age;
# trees and cost varies annually depending upon cycle year
Tree Removal $17,484 $20,000 $72,461 $113,791 $115,000 $125,000 $145,000 $130,000 $130,000 $150,000 $135,000 $52,500 $50,000 $20,000 $20,000
Total cost to remove approx 4500 untreated ash is $1.64
million; total removal cost 2014-2028 = $1.3 million because
some trees will be removed with in-house crew
Tree Watering Forestry Ops
budget $14,100 $19,800 $16,159 $20,000 $20,000 $20,000 $20,000 $20,000 $20,000 $20,000 $20,000 $20,000 $10,000 $10,000 Costs may fluctuate depending upon weather conditions
Wood Debris Forestry Ops
budget $13,125 $31,805 $0 $70,000 $120,000 $120,000 $120,000 $120,000 $120,000 $120,000 $80,000 $25,000 $20,000 $20,000 fluctuates based upon # of ash trees removed
Spoils Pile
(screening/disposal)Not tracked $0
$10,000
(Forestry Ops
budget)
$0 $30,000 $30,000 $30,000 $30,000 $30,000 $30,000 $30,000 $30,000 $30,000 $30,000 $30,000 fluctuates based upon # of trees planted
Education / Outreach Not tracked Not tracked Not tracked Not tracked $10,000 $15,000 $15,000 $10,000 $10,000 $10,000 $5,000 $5,000 $5,000 $5,000 $5,000
Miscellaneous
supplies Not tracked Not tracked $2,723 $2,432 $5,000 $5,000 $5,000 $5,000 $5,000 $5,000 $5,000 $2,500 $2,500 $2,500 $2,500
Biocontrols USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS USDA APHIS
TOTAL SPENT $42,890 $203,225 $245,678 $196,291 $373,709 $500,000 $500,000 $500,000 $500,000 $500,000 $500,000 $375,000 $297,500 $272,500 $272,500
Budgeted $0 $230,000
$246,675
($220,000
+$26,675
carryover)
$220,000
$373,709
($350,000 +
$23,709
carryover)
$500,000 $500,000 $500,000 $500,000 $500,000 $500,000 $375,000 $300,000 $275,000 $275,000
APPENDIX147
Survey Regression Analysis
Linear regression models were built to determine survey
respondent values towards Boulder Forestry activities
and topics. A model comparison approach was used to
identify key indicators for 2 topics:
1. Knowledge and feelings about Boulder Forestry
and Boulder Forestry activities
2. Factors which influence a person’s willingness
and degree of participation in a potential tree
stewardship program
For the first topic, a model comparison approach was used
to identify key indicators for respondents’ knowledge
and feelings about Boulder Forestry and their activities.
First, a single response variable was created by averaging
responses to two questions: Q8, ‘How familiar are you
with the Boulder Forestry responsibilities below?’,
and Q11C, how well respondents agreed or disagreed
with ‘Boulder Forestry’s policies reflect the values of
the Boulder Community’ to create a single new metric
called ‘Knowledge.’ All possible explanatory variables
were then defined, including the demographic battery
from the end of the survey, as well as other values and
attitudes around the urban forest.
A linear regression model was created with every
combination of six or fewer variables. This resulted in
more than 35,000 potential models. Each model was
then ranked based on its performance and complexity. If
Public Survey
Communities can calculate the services of their urban
forest by using a complete inventory (or sample data)
in conjunction with the USDA Forest Service i-Tree
software tools. This state-of-the-art, peer-reviewed
software suite considers regional environmental data
and costs to quantify the ecosystem services unique to
a given urban forest resource.
Individuals can calculate the services of trees to their
property by using the National Tree Benefit Calculator
(www.treebenefits.com/calculator) or with i-Tree
Design. www.itreetools.org/design).
Calculating Individual
Tree Services
APPENDIX 148
The most likely response is to not participate (2), which
indicates a bit of an uphill battle to get residents to
participate in a tree stewardship program. Comments
from the ‘other’ response category in the long-form
survey shed some light on this reluctance. Many
indicated that age and health issues are a barrier to
increased participation, as well as time limitations and
a lack of specific information on specific trees.
For those willing to engage in some level of tree
stewardship, the results indicate that the best models
all identify:
• Participating in a focus group
• The knowledge variable developed above, and
• Feeling at home (Q18)
As the key explanatory variables. This is not surprising
given that those who are more willing to educate
themselves about Boulder Forestry activities, who
agree with them, and who are willing to participate in
a focus group, are more likely to ‘help out’ through tree
stewardship. Similarly, Feeling at home, which is linked
to attachment to one’s community, has been linked to
an increased likelihood of environment action (*). Given
the priority in the 2015 BVCP over quality of life and
sense of place, as well as links above between trees and
neighborhood quality, it would be prudent to link Boulder
Forestry activities to supporting and enhancing the
quality and sense of place for residents’ neighborhoods
as one aspect of the marketing and outreach campaign.
This is particularly true given the emotional and personal
connection many residents expressed to trees in the
Tree Story outreach and comments in the survey.
between the urban forest and neighborhood quality,
and feelings about Boulder Forestry’s current activities.
These explanatory variables were included given their
insight into respondents’ feelings about how much threat
Boulder’s urban forest is under (and therefore Because
of the increased number of variables the number of
combinations that could be explored was reduced, which
created a logistic regression model for all combinations
of five or fewer explanatory variables. This resulted in
over 16,000 models. For Q15, the same approach was
taken, with the same explanatory variables. Because
responses to Q15 have multiple levels, a multinomial
logistic regression was used. Again, a regression was
compared for every combination of five or fewer
explanatory variables, producing 16,000 models. For
Q15, explanatory variables were added to the model and
ranked on its probability that it explains respondents’
level of participation to the question. These levels of
participation are:
1. No response
2. None of them. This is the responsibility of
Boulder Forestry and should be covered by
current taxes
3. I would like to help out but am unable/it’s not
feasible to do so
4. I would be willing to occasionally water a tree
outside my business/residence/workplace
5. I would be willing to water and maintain a tree
outside my business/residence/workplace
6. I would participate in tree planting
7. I would participate in youth education.
any two models had the same performance, the one with
fewer explanatory variables was deemed preferable.
This ranking was quantified using Akaike’s information
criterion (AIC).
The resulting best-fit model had only two explanatory
variables; ‘TimeRecycled’ and ‘FocusGroup’, which
correspond to Q17A and Q30. Additionally, all of the
top-performing models contain these two explanatory
variables, and in every model these two indicators
have the strongest explanatory effect. When examined
more closely, both of these predictors have a significant
positive relationship with the variable Knowledge. In
other words, the more times per year a person recycles,
the more likely they are to be knowledgeable and
agree with Boulder Forestry activities. Similarly, those
willing to participate in a focus group about urban
forest issues are more likely to be knowledgeable and
agree with Boulder Forestry activities. This is supported
by research that shows that current environmental
behavior is associated with a higher level of knowledge
about environmental issues*. Given the high rate
of recycling in Boulder, this may be a good start for
targeted marketing outreach.
For the second topic, two questions were asked: 1)
What factors indicate a willingness to participate in a
potential tree stewardship program Q14, and 2) To what
degree would respondents be willing to participate (i.e.
level of tree stewardship) Q15. For both questions a
similar approach was used as for the above analysis.
The results for Q14 showed that the explanatory
variables included the demographic variables, the new
knowledge metric, and questions 3, 7, and 11, which
asked about threats to the urban forest, associations
APPENDIX149
Survey Graphs
Long-Form Survey Questions
The following charts represent th responses to the
2Forks long-form survey questions. Charts were created
only from questions with easily graphed responses.
Some questions, such as open response questions, were
not charted. Thus, some questions do not have a chart.
APPENDIX 150
APPENDIX151
APPENDIX 152
APPENDIX153
APPENDIX 154
APPENDIX155
APPENDIX 156
APPENDIX157
APPENDIX 158
APPENDIX159
APPENDIX 160
Short-Form Survey Questions
The following charts represent th responses to the 2Forks
short-form survey questions. Charts were created only
from questions with easily graphed responses. Some
questions, such as open response questions, were not
charted. Thus, some questions do not have a chart.
APPENDIX161
APPENDIX 162
APPENDIX163
Table 1: Land Cover Classes
Table 2: Benchmark Values
Table 3: Boulder’s Population
Table 4: Ecosystem Services From Tree Canopy
Table 5: Forest Fragmentation
Table 6: Priority Planting Sites
Table 7: Replacement Value of Top 5 Species
Table 8: Operating Forestry Budget (2017)
Table 9: Average tree care costs (2012-2016)
Table 10: Boulder’s Urban Forest Budget in Comparison with Other Communities
Table 11: Funding Scenarios
Chart 1: Land Cover
Chart 2: Rent vs Own
Chart 3: Municipal Compensation Requirements
Chart 4: Public vs Private Trees
Chart 5: Comparison Community Canopy Cover
Chart 6: Age Distribution of Boulder's Public Trees
Chart 7: Annual Services From Prevalent Public Tree Species
Chart 8: Return on Investment for Public Trees
Chart 9: Overall Condition of Public Trees
Chart 10: History of Tree Planting & Removal – Boulder Forestry
Chart 11¬: Ash as % of Public Trees
Chart 12: Approximate Public Service Requests Per Year
Chart 13: Municipal Budget
Chart 14: Survey Respondent Demographics
Chart 15: Survey Respondent Associations and Values
2, 45
4
20
47
48
50
51
79
81
82
84
2, 45
20
43
44
49
52
53
54
54
58
67
77
80
99
100
Table of Figures
Map 1: Land Cover
Map 2: Canopy in Boulder and Open Spaces and Mountain Parks
Map 3: Canopy Cover by Maintenance District
Map 4: Forest Fragmentation
Map 5: Priority Planting
Figure 1: Cooling Effect of Tree Shade (Balogun et al., 2014)
Figure 2: Impact of Trees and Vegetation (Akbari, 2002)
Figure 3: High Detail Forest Fragmentation
Figure 4: High Detail Priority Planting
2, 46
21
46
48
50
18
18
48
50
APPENDIX 164
Arboriculture
• The science, art, technology, and business of tree
care.
Community Urban Forest
• The collection of publicly owned trees within an
urban area, including street trees and trees in
parks and other public facilities.
Heritage Tree
• A large, individual tree with unique value, which is
considered irreplaceable due to age, size, rarity,
aesthetic, botanical, ecological, and/or historical
value.
Inventoried Trees
• Includes all public trees collected in the inventory
as well as trees that have since been collected by
city staff.
Life-Cycle Analysis
• Life Cycle Assessment is a systematic inventory
and analysis of the environmental effect that
is caused by a product or process starting from
the extraction of raw materials, production, use,
through to the waste management.
Tree Canopy
• The layer of leaves, branches, and stems of trees
that cover the ground when viewed from above.
Tree in Proximity to Trails/Facilities
• A tree that, as the result of size and location,
has the potential to impact or interfere with the
use, safety, and/or condition of a defined trail,
structure, or facility (e.g., picnic table, bench,
parking area, etc.)
Urban Forest
• The collection of privately owned and publicly
owned trees and woody shrubs that grow within
an urban area.
Urban Forestry
• The cultivation and management of native or
introduced trees and related vegetation in urban
areas for their present and potential contribution
to the economic, physiological, sociological, and
ecological well-being of urban society.
Natural Area
• A defined area where native trees and vegetation
are allowed to grow and reproduce naturally with
little or no management except for control of
undesirable and invasive species.
Private Tree
• A tree located on private property, including
residential and commercial parcels.
Public Tree
• A tree located in the public ROW, city park, and/
or city facility.
Right Tree Right Place
• The practice of installing the optimal species
for a particular planting site. Considerations
include existing and planned utilities and other
infrastructure, planter size, soil characteristics,
water needs as well as the intended role and
characteristics of the species.
Significant Tree
• A healthy evergreen or deciduous tree of specific
size as defined by policy and/or regulation.
Structural and Training Pruning
• Pruning to develop a sound and desirable scaffold
branch structure in a tree and to reduce the
likelihood of branch failure.
Dictionary
APPENDIX165
Soil Volume and Tree
Stature
Above: Tree growth is limited by soil volume. Larger stature trees require larger
volumes of uncompacted soil to reach mature size and canopy spread (Casey Trees,
2008).
Above: General relationship between soil volume requirements and
mature tree size (James Urban, various sources, 1992).
APPENDIX 166
Above: Bioswales are landscaped drainage areas with gently sloped sides designed to
provide temporary storage while runoff infiltrates the soil. They reduce off-site runoff
and trap pollutants and silt.
Above: Stormwater tree pits are designed to
collect runoff from streets, parking lots, and
other impervious areas. Stormwater is directed
into scuppers that flow into below-grade planters
that then allow stormwater to infiltrate soils to
supplement irrigation.
Alternative Planter
Design
APPENDIX167
Above: Structural soil is a highly porous, engineered aggregate mix,
designed for use under asphalt and concrete as a load-bearing and leveling
layer. The created spaces allow for water infiltration and storage, in
addition to root growth.
Above: Suspended sidewalks use pillars or structured cell systems to
support reinforced concrete, increasing the volume of uncompacted soil in
subsurface planting areas and enhancing both root growth and stormwater
storage.
APPENDIX 168
Above: Permeable pavements allow stormwater and oxygen to infiltrate the surface, promoting
tree health and groundwater recharge.
APPENDIX169
Standard Tree Planting
Detail (Placeholder)
Right: Standard Detail
of Tree Protection
Measures
APPENDIX 170