HomeMy WebLinkAboutIowa City Urban Forest Management Plan 11-28-18
URBAN FOREST
MANAGEMENT PLAN
2018 | IOWA CITY, IA
Urban Forest
Management Plan
- IOWA CITY, IA -
Acknowledgements
Accepted in November 2018
Cover photo source: Think Iowa City
All other photos unless noted are from the City of Iowa City
- THE CITY OF IOWA CITY -
Parks and Recreation Department
Parks and Forestry Division
City of Iowa City Parks and Recreation Commission
The City Council of Iowa City
Citizens of Iowa City
- THE IOWA DEPARTMENT OF NATURAL RESOURCES URBAN FORESTRY -
- PLAN-IT GEO, LLC -
City of Iowa City | 410 E Washington St | Iowa City, IA | 52240 | www.icgov.org
Our vision for the future of Iowa City is to create a healthy and sustainable
urban forest that is properly managed and cared for, benefiting our citizens with
improved economic and environmental well-being,
increasing public safety, and enabling our employees to provide cost-
effective maintenance
Our urban forest will have a large variety of trees consisting of various sizes, ages, and
species. The trees will be selected and maintained according to the Best Management
Practices (BMPs) established by the International Society of Arboriculture (ISA)
Table of Contents
Executive Summary I
Introduction 1
OVERVIEW OF THE BENEFITS OF IOWA CITY’S TREES 2
PURPOSE OF THE URBAN FOREST MANAGEMENT PLAN 3
State of the Urban Forest 6
OVERVIEW OF THE CITY’S URBAN FORESTRY PROGRAM 7
TREE AND PLANTING SITES INVENTORY SUMMARY 13
Criteria & Indicators for Urban Forest Goals & Strategies 24
IOWA CITY’S 20-YEAR FRAMEWORK FOR URBAN FOREST… 25
Adaptive Management & Monitoring 31
RECOMMENDED METHODS FOR MONITORING PERFORMANCE… 33
First 5-Year Urban Forest Management Plan Strategies 36
EDUCATION 38
ORGANIZATION & MANAGEMENT 40
PLAN IMPLEMENTATION 42
URBAN FORESTRY PROGRAM PROJECT FUNDING 43
Summary & Conclusion 44
Appendices i
APPENDIX A. URBAN FOREST SUSTAINABILITY &… ii
APPENDIX B: STREET & PARK TREE INVENTORY METHODOLOGY iv
APPENDIX C: COUNT OF TREES BY CITY PARKS & TRAILS vii
APPENDIX D: BEST PRACTICES FOR TREE PRESERVATION ix
APPENDIX E: TREE MAINTENANCE BEST PRACTICES xi
APPENDIX F: URBAN FORESTRY RESOURCES xvi
APPENDIX G: TREE & PLANTING SITE MAPS xix
APPENDIX H: EAB MANAGEMENT GUIDELINES & COMMUNITY… XXV
Tables & Figures
LIST OF TABLES
Table 1. Summary of the status of City of Iowa City’s urban forestry program and resource 4
Table 2. Summary of the ordinance review 9
Table 3. Existing efforts with urban forestry references presenting opportunity 10
Table 4. Departments and entities that impact urban forest management 11
Table 5. Examples of potential partners in implementing strategies of the UFMP 12
Table 6. Parks with the highest tree count 14
Table 7. Top 10 genera 15
Table 8. Top 10 species 15
Table 9. Summary of maintenance needs for street and park trees 19
Table 10. Summary of maintenance need by street and park 19
Table 11. Vegetation Resource – Performance Indicators 25
Table 12. Resource Management – Performance Indicators 26
Table 13. Community Framework – Performance Indicators 29
Table 14. Institutional Framework – Performance Indicators 30
Table 15. Goal One strategies 38
Table 16. Goal Two strategies 40
Table 17. Goal Three strategies 42
Table 18. Goal Four strategies 43
Table 19. Summary of the 2018 Iowa City Urban Forest Management Plan 45
LIST OF FIGURES
Figure 1. Summary of the benefits of City-managed trees 1
Figure 2. Plan development process 3
Figure 3. Land use distribution of inventoried trees 14
Figure 4. Top 10 tree genera 15
Figure 5. Top 10 tree species 15
Figure 6. Iowa City's tree diameter distribution versus ideal distribution 16
Figure 7. Condition of street and park trees 17
Figure 8. Comparison of the condition of street and park trees 17
Figure 9. Condition distribution among the top 10 species 17
Figure 10. Count of tree observations 18
Figure 11. Maintenance needs summary 19
Figure 12. Summary of street and park tree removals by DBH 19
Figure 13. Summary of the tree risk assessment for street and park trees 20
Figure 14. Map of trees with a risk rating of Extreme 20
Figure 15. Summary of infrastructure conflicts with street and park trees 21
Figure 16. Condition classes of ash trees 22
Figure 17. DBH distribution of ash trees 22
Figure 18. Key characteristics for ash (Fraxinus) tree and emerald ash borer…ID 22
Figure 19. Location and size of planting sites 23
Figure 20: The management plan implementation process 32
Figure 21. The benefits and values of City-managed trees 45
Figure 22. Types of tree pruning xii
Figure 23. Types of pruning cuts and the proper branch cutting technique xiii
Figure 24. Example of trees directionally pruned for clearance from power lines xiv
Figure 25. Example of branches to be pruned for newly planted trees to promote good structure xv
- IOWA CITY, IA -
URBAN FOREST
MANAGEMENT PLAN
October 2018
Iowa City Urban Forest Management Plan | 1
Executive Summary
INTRODUCTION
Iowa City is dedicated to building a thriving urban and
community forest for a healthy and vibrant city. Realizing the
community forest is a valued asset, Iowa City, herein referred
to as “the City”, invested in a collaborative planning process,
involving extensive urban forest resource and program
analysis to develop a clear, concise and timeline oriented
Urban Forest Management Plan. The overall goal of the
planning process was to develop a sustainable Urban Forestry
Program, led by the Division of Parks and Forestry, who is
committed to this measured, monitored, and strategic long-
term investment. The strategic planning process engaged City
staff, with the interest of the community, to evaluate all
aspects and components of a comprehensive community
forestry program. Together, this team developed goals and
strategies to guide the City’s Urban Forestry Program over the
next 20 years. Clear criteria and performance indicators of
urban forestry and the measures to monitor progress will
allow for future planning and adaptive management over the
coming years with the clear goals for the community set.
Bringing to light the importance of urban forest planning, in
2014, the emerald ash borer (EAB) insect pest was found in
the City. This Asian pest feeds on ash trees and quickly causes
tree mortality. With approximately 2,000 ash trees across
city-maintained areas, Parks and Forestry and partners are
actively developing a plan to address EAB. Additionally,
community outreach is being conducted due to the substantial number of ash trees on private property. Threats
to the urban forest such as EAB and unforeseen pests necessitates development of this Urban Forest
Management Plan. Learn more about EAB at https://www.icgov.org/emeraldashborer. The EAB infestation, past
pest and disease issues such as Dutch Elm Disease, and potential future issues warrant the need for proper urban
forest planning.
Starting the ambitious planning effort began with the Parks and Forestry spearheading the comprehensive street
and park tree inventory of trees managed by the City. Over 45,000 trees were inventoried to collect tree species,
size, condition, and maintenance needs. Over 5,000 potential tree planting sites were also mapped, which will
help as the City implements the Plan to increase tree diversity and overall tree canopy, providing more
environmental, economic, and social benefits to the community. The information collected from the inventory
informed the strategies in the Plan for diversifying the urban forest and prioritizing risk tree and routine
maintenance. With this data, the value of the city-managed trees can also be quantified, providing valuable
information to the community as the City pursues enhanced community interest, support, and engagement with
the urban forest.
Image Source: Travel Iowa
Iowa City Urban Forest Management Plan │ I
Iowa City Urban Forest Management Plan | 2
The Benefits & Value of the City-Managed Trees
The trees in Iowa City provide value in terms of increased property values, air quality improvements, reduction
in stormwater values and an increase in water quality, energy savings from the shade of their canopy and
protection from cool winds, and their ability to sequester and store carbon. These values, originating from
research conducted by the U.S. Forest Service in 13 states across the country, equate to nearly
$4.2 million total annual value to Iowa City
The City wants to sustain and enhance these benefits trees provide to the community by developing and
following this strategic Urban Forest Management Plan. At the same time, stresses from the urban environment
including air pollution, pests and diseases such as emerald ash borer, invasive species, climate change, damage
by vehicles, increased impervious surface, infrastructure conflicts, soil compaction, and maintenance neglect
reduce the diversity and magnitude of these benefits and may lead to tree-related problems. With this
understanding it was imperative that the City develop an Urban Forest Management Plan which will be a
roadmap that first looked at the questions of What do we have? What do we want? How do we get what we
want? and, How are we doing? The following will provide an overview of this process completed for the City to
develop the goals, strategies, and measures to answer these questions.
Iowa City Urban Forest Management Plan │ II
Iowa City Urban Forest Management Plan | 3
WHAT DO WE HAVE?
The first step in the planning process is to get baseline information about the natural resource and the
programs and factors influencing it. An analysis of the street and park tree inventory was conducted to
understand Iowa City’s urban forest characteristics and maintenance needs and to identify trends.
Of the 45,000 street and park trees,
there are nearly 180 unique tree
species, with the top 10 shown in the
chart (right). It includes large canopy
trees like silver maple and northern
hackberry as well as smaller, flowering
trees like crabapple. One concern that
will be addressed is the abundance of
green ash and other ash (3,516 trees)
which are at risk to the emerald ash
borer, a pest that quickly leads to tree
mortality causing surges of immediate
tree removals. The charts below show
that overall, the trees in the City are in
good or fair condition with an average
diameter of 12 inches but 18% require
immediate priority pruning and 2,110
trees are recommended for removal.
8.1%
6.4%
6.1%
5.8%
4.9%
4.4%
4.0%
3.8%
3.7%
2.6%
Top 10 tree species in Iowa City Silver maple
Northern hackberry
Green ash
Crabapple
Mulberry
American elm
Black cherry
Boxelder
Honeylocust
Norway maple
0
2000
4000
6000
8000
10000
12000
14000 Comparison of the condition of
street and park trees in Iowa City
Street Park
0
2000
4000
6000
8000
10000
12000
14000
16000
0-6in 6-12in 12-18in 18-24in 24-30in >30in
Iowa City's tree diameter distribution
5%
1%0%
72%
3%
18%
Maintenance needs summary of street and park trees
Removal High Priority Pruning
Immediate Priority Pruning Routine Pruning
Training Pruning None Needed
Iowa City Urban Forest Management Plan │ III
Iowa City Urban Forest Management Plan | 4
An analysis of the urban forest program was also conducted using the U.S. Forest Service’s Urban Forest
Sustainability and Management Audit that evaluates every aspect of urban forest management and condition
by categories such as Management Policy and Ordinances, Professional Capacity and Training, and Funding and
Accounting. This audit identified the gaps in the City’s urban forest as it pertains to the Vegetation Resource (the
trees), the Resource Management (the staff), Community Framework (the people), and Institutional Framework
(the agencies) to inform the goals, strategies, and measures provided in this Plan as described below.
WHAT DO WE WANT?
Based on the audit, gaps were identified and the status of each Criteria and Performance Indicator as it pertains
to the vegetation resource, resource management, community framework, and institutional framework, were
documented on the spectrum (low, moderate, good,
optimal). Each criterion has the information to
determine where the City is at on the spectrum and
how to get “What we want”.
HOW DO WE GET WHAT WE WANT?
With an understanding of the City’s current urban
forestry program and tree resource based on the
analyses, and the desire for “Optimal” in the Criteria
and Performance Indicator spectrum, goals and
strategies were developed. Each goal has an
overarching theme and contains the strategies to
achieve the goal as well as the reference of the
Criteria it addresses and the responsible agency for
initiating it and monitoring progress.
ARE WE GETTING WHAT WE WANT?
Using an adaptive management approach will require the
consistent monitoring of all the City’s criteria for urban
forest sustainability. The City will be able to judge if its’
new approaches to urban forest conservation are being
effective, develop relationships between management
actions and outcomes, and identify significant trends.
This will allow the City to adjust management actions
over time as changes occur both in the
physical/biological environment and in the expectations
of the City’s residents.
Iowa City’s urban and community forest is a defining and valued characteristic of making the city a desirable
place to live, work, and play. It is a resource that has a history and legacy of care and management; however,
the resource could be more efficiently managed and enhanced. The assessment, criteria and indicators, goals
and strategies, and measures for adaptive management that are presented in this Urban Forest Management
Plan have been created to provide a framework to effectively, proactively, and sustainably manage trees. While
it will take work and additional resources to implement the UFMP, its implementation will help ensure that Iowa
City’s urban and community forest will continue to be a valued part of the community.
EDUCATION
Goal One: Promote proper tree care through
education and enforcement
ORGANIZATION & MANAGEMENT
Goal Two: Improve efficiencies and collaborate to
propel urban forest management
PLAN IMPLEMENTATION
Goal Three: Build the team and the
reinforcements to implement the Plan
URBAN FORESTRY PROJECT FUNDING
Goal Four: Seek alternative mechanisms for
funding and projects to accomplish the strategies
Iowa City Urban Forest Management Plan │ IV
Iowa City Urban Forest Management Plan | 5
“Urban trees and forests are considered integral to the sustainability of
cities as a whole. Yet, sustainable urban forests are not born, they are
made. They do not arise at random, but result from a community-wide
commitment to their creation and management.”
| Clark et al.: Urban Forest Sustainability
Iowa City Urban Forest Management Plan | 1
Introduction
The trees found in our transportation corridors, parks, yards, and natural
areas constitute an “urban forest” and are valuable community assets that
play a major role in sustaining the quality of life enjoyed by residents of
Iowa City. Although these natural features may appear long-lived, resilient,
and ubiquitous; in reality, they have inherent limitations and a set of
threats that necessitate the City to take steps to protect, manage and
expand this resource so future generations will continue to enjoy its
services and benefits.
The term “urban forest” encompasses a diverse range of trees and forests
found throughout urban, suburban, and exurban landscapes in the City.
This variety requires the City to adopt a wide-range of management
approaches. The strategies used to manage native forest ecosystems only
have limited application to managing street and residential trees and, vice-
versa. There is a growing consensus that urban forests are an important
component of community infrastructure and a resource that must be
carefully managed, protected, and included in planning efforts.
The inherently close interaction between people and trees in Iowa City
requires active and diligent management of the urban and community tree
and forest resources to ensure public safety. A scientifically grounded
management program is necessary in order to maximize the value and
minimize the risk associated with trees within this complex and dynamic
human ecological system in Iowa City. The initial step in meeting these
challenges is the identification and organization of baseline information in
the form of an inventory that describes the location, composition,
structure, and health of the trees. The 2016-2018 Street and Park Tree
Inventory and an analysis of the City’s urban forestry program
accompanied the development of this management plan designed to
enhance urban forest sustainability.
This Plan was developed through a collaborative effort supported by the
City. It summarizes the urban forestry program and the resources in place
to protect and enhance it. The Plan provides the goals, strategies, and
measures required to develop and maintain a thriving urban forest for City
residents and future generations to enjoy.
“Urban forest sustainability is defined in terms of maintaining healthy
and functional vegetation and associated systems that provide long-
term benefits desired by the community. This definition places signif-
icant emphasis on the role of the communities and institutions who
manage the urban forest.”
| Dwyer et al. 2003
Iowa City Urban Forest Management Plan | 2
OVERVIEW OF THE BENEFITS OF IOWA CITY’S TREES
Iowa City’s urban forest plays a significant role in maintaining the health and vitality of urban life. The urban
forest provides a wealth of benefits to neighborhoods and residents through the reduction of energy
consumption, the removal of pollutants from the air and water, reduction in stormwater flows, increased
valuation of private property, increased worker productivity, reduction in stress and violent crime, as well as
providing recreational opportunities and aesthetic diversity. In summary, urban forests provide “triple bottom
line” benefits: social, economic, and environmental.
Trees provide services which can be assigned a financial value, using the peer-reviewed i-Tree research, which
are summarized below based on the 2016-2018 street and park tree inventory.
The total annual benefits of Iowa City’s inventoried trees (45,014 trees, 43,898 with benefits values) are
estimated at $4,173,539 (street trees make up 66% of that value). Stormwater retention represents 36% of the
monetary value ($1,525,508) followed by property values. Increases in property values are estimated at over
$986,171 though it should be noted that the research is dated and uses regional estimates. It is still important
to demonstrate that trees add value to properties in terms of aesthetics, well-being, increased tourism, sense of
community, etc. Energy savings is valued at $459,295, or 11% of the total value. If the young trees continue to
grow and are maintained properly and new trees are planted after removals, these benefits are likely to sustain
and potentially increase.
At the same time, stresses from the urban environment including air pollution, pests such as emerald ash borer
(EAB), diseases, invasive species, climate change, damage by vehicles, increased impervious surface,
infrastructure conflicts, soil compaction, and maintenance neglect reduce the diversity and magnitude of these
benefits and may lead to tree-related problems. This understanding influenced the desire and, ultimately, the
need to develop Iowa City’s Urban Forest Management Plan.
Figure 1. Summary of the benefits of City-managed trees
Iowa City Urban Forest Management Plan | 3
This strategic plan for the management of Iowa City’s urban forest addresses the numerous challenges to
growing and maintaining a healthy urban forest in an efficient manner. Management of the urban forest, with
its long biological life cycles and slow growth, is a long-term investment. The Plan recognizes that attempts to
enhance its vigor, longevity, and diversity must reflect this reality.
PURPOSE OF THE URBAN FOREST MANAGEMENT PLAN
Understanding the benefits and functions of our urban forest, the City has developed this Urban Forest
Management Plan.
“Without a management plan, the governments and individuals responsible for taking care of
an urban forest will not be effective in meeting the true needs of the trees and the community.
A management plan establishes a clear set of priorities and objectives related to the goal of
maintaining a productive and beneficial community forest.” │ American Public Works
Association, 2007
Plan Purpose
- Summarize the current state of the urban forest resource, resource management, community framework,
and institutional framework
- Provide the criteria and indicators for achieving goals of sustainable urban forest management
- Provide methods of measures and monitoring of the criteria and indicators to enable adaptive management
- Provide goals and strategies to advance the City along the criteria and indicators of urban forestry spectrum
How the Plan Was Developed
Developing the Urban Forest Management Plan was a gradational process where the results of each step
informed the next, leading to development of the goals, strategies, and adaptive management measures.
Program & Data Analysis
First, research was conducted to gather information about the City’s urban
forest. This involved an extensive review of existing plans, policies,
ordinances, practices, and initiatives.
Data pertaining to the City’s urban forest such as the street and park tree
inventory were gathered and analyzed to identify the urban forest
structure, maintenance needs, and potential risks. Results from the analysis
were then applied to the Urban Forest Program Audit (described on the
next page) and ultimately, to the Plan’s Goals and Strategies.
After initial information and data were gathered and analyzed, the City staff
provided additional input to inform development of the Plan.
Criteria & Performance Indicators │Measures, Goals, & Strategies
Using the results of the steps listed above, the Plan was developed by establishing Criteria and Performance
Indicators for urban forest management and sustainability. This process identifies where the City is currently on
a management and sustainability spectrum and a description of the criteria for advancing on the spectrum.
Table 1 on the next page summarizes the outcomes which are described in the Criteria & Indicators for Urban
Forest Goals & Strategies section. This shows Iowa City’s status. While the City is achieving near optimal levels
for some elements, there exists a need for improvement in others.
Based on the City’s current status, goals and strategies were developed to advance the City’s urban forest
resource and program along this spectrum. Monitoring and methods for measuring progress were established
to enable the City to evaluate the status and adjust and adapt strategies accordingly.
Program & Data Analysis
Criteria &
Performance
Indicators
Measures,
Goals,
& Strategies
Figure 2. Plan development process
Iowa City Urban Forest Management Plan | 4
Table 1. Summary of the status of the City of Iowa City’s urban forestry program and resource
The Urban Forest
Sustainability and
Management Spectrum
Category Spectrum Level: Low Moderate Good Optimal Total
The Urban Forest
(“Vegetation Resource”) 0 3 1 1 5
Management of the Urban Forest
(“Resource Management”) 2 5 7 3 17
Community & the Urban Forest
(“Community Framework”) 1 2 1 0 4
Agencies & the Urban Forest
(“Institutional Framework”) 0 4 0 0 4
Total 3 14 9 4 30
As seen in the table above, overall, the City resides in the “Moderate” level of urban forest management and
sustainability according to the Criteria & Performance Indicators. These criteria and indicators were established
by the U.S. Forest Service and industry professionals and were tailored to Iowa City. Of the total 30 urban forestry
criteria, the City is moderately performing 14 of these instead of performing or achieving these at the “Good” or
“Optimal” level. This illustrates the need for improved urban forestry management. Criteria where the City is
performing lower than “Good” were evaluated to develop the goals, strategies, and adaptive management
measures.
The following describes the planning process in more detail.
URBAN FOREST PROGRAM AUDIT
To effectively provide urban
forest goals and strategies, the
City’s urban forest and the
management program were
reviewed and analyzed through
an extensive research and
information gathering process.
The process involved utilizing a
model for strategic urban forest
planning that was first introduced by James R. Clark et al. (1997). It recommends the use of a series of
management criteria and performance indicators (C&I) to measure urban forest management success. Built into
this process for the City’s Plan is the updated comprehensive criteria and performance indicators developed by
W. Andy Kenney et al. (2011). See the "Criteria Key" in the Recommended Methods for Monitoring Performance
Criteria section for an adapted list of these C&I’s for Iowa City.
To summarize this approach, the Vegetation Resource criteria and performance indicators are used to monitor
the urban forest resource to provide an accurate assessment within the City’s changing environment. The
Community and Institutional criteria and performance indicators assess changing economic and social conditions
The Urban Forest Sustainability & Management Audit for analyzing the City’s program
Program & Data Analysis → Criteria and Performance Indicators → Measures → Goals & Strategies
Iowa City
Iowa City Urban Forest Management Plan | 5
critical to urban forest sustainability. The Resource Management criteria and performance indicators provide
the means for measuring how well management is proceeding in sustaining or enhancing these urban forest
conditions and for tracking subsequent changes.
The process of analyzing the urban forest following these respected guides was conducted using the U.S. Forest
Service’s Urban Forest Sustainability and Management Audit which applies the aforementioned resources. This
audit completed for Iowa City involved extensive information and document gathering and research to identify
policies, practices, programs, and standards pertaining to 11 categories of urban forest sustainability and
management as defined by Clark et al. (1997), Kenney et al. (2011), and the U.S. Forest Service.
Categories of the Urban Forest Sustainability and Management Audit and Percent Achieved
- Management Policy and Ordinances: 64% Achieved
- Professional Capacity and Training: 38% Achieved
- Funding and Accounting: 58% Achieved
- Decision and Management Authority: 75% Achieved
- Inventories: 62% Achieved
- Urban Forest Management Plans: 75% Achieved
- Risk Management: 56% Achieved
- Disaster Planning: 36% Achieved
- Practices, Standards, and BMPs (Best Management Practices): 83% Achieved
- Community: 71% Achieved
Overall: 68% Achieved (view a detailed summary of the Audit results in Appendix A)
Each category has a series of elements pertaining to the category. For example, the Management Policy and
Ordinances category has the elements, “Climate Change”, “No Net Loss”, “Risk Management”, “Tree Canopy
Goals”, “Tree Protection”, “Utility”, “Human Health – Physical & Psychological”, “Wildlife Diversity / Habitat /
Protection”, “Performance Monitoring”, “Public and Private [tree] Ordinances”, “Development Standards”,
“High-Conservation Value Forests”, and “Urban Interface (WUI)”. All available documents, plans, etc. were
reviewed, noted, and tallied in the audit worksheet. After the research and discovery phase, each category’s
element was “ranked” as 0) Not Practiced, 1) In Development, 2) Adopted Common Practice, 3) Exceeds
Common Practice based on the City’s current status. In the audit, this ranking provides an evaluation of the level
at which the City is achieving each category and overall urban forest management and sustainability.
This urban forest audit identified the gaps in the City’s urban forest as it pertains to the Vegetation Resource,
the Resource Management, Community Framework, and Institutional Framework to inform the goals, strategies,
and measures provided in this Plan. For more information on the U.S. Forest Service’s Urban Forest Sustainability
and Management Audit, visit https://www.interfacesouth.org or view an example in Appendix A.
STREET AND PARK TREE INVENTORY ANALYSIS
In addition to the analysis of the urban forestry program and the categories of urban
forest sustainability and management, a street and park tree inventory was
conducted beginning in December of 2016 and completed in March of 2018. This
inventory was completed by International Society of Arboriculture Certified Arborists
using the tree inventory software, Tree Plotter, developed and used by Plan-It Geo,
contracted for the inventory. For a description of the tree inventory methodology
and protocols, see Appendix B.
This Plan summarizes the City’s tree structure, maintenance needs, and potential
risks which were used to inform maintenance recommendations and overall urban
forest management and enhancement while pursuing sustainability of the resource. Tree inventory crew
Image Source: Plan-It Geo
Iowa City Urban Forest Management Plan | 6
State of
the Urban Forest
To summarize the analysis of the urban forest resource and programs impacting it which informed the goals
and strategies in this Plan
Image Source: Plan-It Geo
“What
Do We
Have?”
Iowa City Urban Forest Management Plan | 7
OVERVIEW OF THE CITY’S URBAN FORESTRY PROGRAM
Iowa City, located in Johnson County, IA was established in 1839 and encompasses 25 square miles, making it
one of Iowa’s larger communities with a July 2016 population estimate of 74,398. As part of the development of
the City’s IC2030 Comprehensive Plan Update, the public was asked what they like most about the City in one
word. Based on the results, elements such as parks, trails, community, walkable, neighborhoods, and green were
some of the highest counts. This emphasizes the important role that the City’s urban forestry program has in
creating and maintaining a place that the community enjoys.
Staffing
The Parks and Forestry Division of the Parks and
Recreation Department is responsible for the care and
maintenance of all City-owned trees located in parks,
easements, and City rights-of-way. Other duties
include snowplowing in the winter and other
miscellaneous duties to assist in the maintenance of
public green space. There are 1,800 acres of managed
parks and natural areas throughout the City and the
recent inventory tallied nearly 50,000 trees in parks
and along streets that Parks and Forestry manages.
The staff within the Division includes the
Superintendent, a Senior Maintenance Worker
(SRMW), one Maintenance Worker III (MWIII), one
Maintenance Worker II (MWII), and two Maintenance
Worker I (MWI) positions. Also, during the months of
April through October a Variable Employee is staffed.
TRAINING AND EXPERIENCE REQUIREMENTS
SRMW: Degree in Forestry or related field,
International Society of Arboriculture (ISA) Certified
Arborist certification, Pesticide Applicator License, and
a Commercial Driver’s License (CDL).
MWIII: High School degree and two years of
experience, Pesticide Applicator License, and CDL. In
addition to these requirements, the current MWIII
staff is also an ISA Certified Arborist, ISA Certified
Municipal Arborist, and has the ISA Tree Risk
Assessment Qualification (TRAQ).
MWII: Two years of experience and a CDL.
MWI: One year of experience and a CDL.
Funding & Budget
For the Parks and Forestry Division to operate, the
majority of the budget comes from the General
Fund and approximately 10% comes from the Road
Use Tax. Variable, small amounts also come from
the Division’s Memorial Tree Fund.
BUDGET SUMMARY
(2018)
Tree Planting & Initial Care……………….. $67,145.00
Tree Maintenance & Removals..……… $123,000.00
Management & Wages …………….……. $479,551.15
Equipment, Operating Supplies, Training, and
Tech Support………………………………….. $110,778.00
In addition to the General Fund and Road Use Tax,
the Division actively pursues available grants for
tree planting and maintenance. Each year, the
Division orders seedlings from the State Nursery
for free to do timber stand improvement projects
in several parks with wooded areas. For areas
along streets within the public right-of-way, the
Division often utilizes the MidAmerican Energy
“Plant Trees, Save Energy” program. The amount
varies each year for the program’s Trees Please
Grant. For 2018 the City will receive $10,000.
Program & Data Analysis → Criteria and Performance Indicators → Measures → Goals & Strategies
Iowa City Urban Forest Management Plan | 8
Current Tree Maintenance Practices
The Parks and Forestry Division operates and maintains the urban forest with an established maintenance and
planting schedule. The 2016-2018 street and park tree inventory consists of over 45,000 trees and nearly 5,000
planting sites. The summary of this data is provided in Tree and Planting Sites Inventory Summary section. The
purpose of the inventory was to gather accurate and current data about the structure of the urban forest as well
as the maintenance needs and priorities. This Plan provides recommendations for maintenance program
improvements.
The City has staff and equipment for conducting tree maintenance and planting in-house. Maintenance
equipment includes a pickup truck, two wood and debris chippers, a grapple wood truck, and a watering trailer.
Depending on the size of the tree, the type of equipment, and existing workloads, maintenance is contracted.
The City Code established the location and responsibility of trees within the public right-of-way. It also provides
the site development and design standards, tree nursery standards, and proper maintenance procedures. These
ordinances and standards from the City Code (City Code: 16-1A) pertaining to the urban forest are summarized
in the Ordinance Review & Summary section of this Plan. Recommendations for adding and/or improving these
are provided in the Criteria & Indicators for Urban Forest Goals & Strategies section.
SUMMARY OF THE CITY’S MAINTENANCE PRACTICES
• Routine pruning such as the removal of dead, disease, dying, damaged, poor structured tree limbs, and for
clearance is conducted daily and requests from the public are integrated into the pruning schedule.
• Tree risk management is conducted during routine pruning and the updated inventory will assist the Parks
and Forestry with prioritization and scheduling.
• MidAmerican Energy is responsible for tree pruning for clearance around power lines.
• Young tree pruning is completed during the winter months.
• Oaks (Quercus) are only pruned in the winter months to prevent oak wilt (Bretziella fagacearum). If oaks
need to be pruned outside of this timeframe, pruning cuts are treated.
• Trees requiring immediate removal or pruning are addressed as soon as possible using in-house and
contracted tree care companies depending on the extent and workloads.
• Newly planted trees are typically mulched and the trees are watered for the first 2 years depending on the
level of precipitation. After 2 years, the adjacent property owner is asked to assist. Information on proper
tree care and watering requirements is provided.
• The number of trees planted on an annual basis is between 150 and 200 trees depending on the season and
available staff time and resources.
• The tree maintenance staff understand locations where trees are needed. The 2016-2018 tree and planting
site inventory will assist staff in prioritizing locations for planting.
• If the property owner has public right-of-way adjacent to his or her property and would like to plant a tree,
a tree planting permit application must be completed and sent to the City for review. Optionally, the
property owner may contact the City to have a tree planted for them though the planting will depend on
the specific situation, whether it is a replacement tree, and current Forestry budget constraints. The Planting
in the Right-of-Way brochure and Tree Planting Permit application are available online.
• The City has tree inventory management software known as Tree Plotter and Work Order Management that
contains all inventory points and data. This Plan provides a summary of the data and will assist the
maintenance staff with future maintenance and planting.
• Minimal vegetation control chemicals are used throughout the City’s managed parks and natural areas. Turf
areas and open green spaces are not routinely sprayed to control undesirable vegetation. Mechanical
techniques (hand weeding, mowing/trimming, over-seeding and mulching) and landscape design techniques
(such as prairie-style and new perennial design) are used to reduce the need for vegetation control chemical
use.
Iowa City Urban Forest Management Plan | 9
Ordinance Review & Summary
To provide urban forest program goals, recommendations, and strategies, an extensive ordinance, policy, and
practices review was conducted following the U.S. Forest Service’s Urban Forest Sustainability and Management
Audit. The following provides a high-level summary of these pertaining to or affecting urban forestry and is not
intended to be comprehensive but to highlight the importance placed on urban trees. The City Code is available
at: http://www.sterlingcodifiers.com/codebook/index.php?book_id=953.
Table 2. Summary of the ordinance review
Element Title Description (summarized)
No Net Loss of
Tree Canopy
City Code, Title 14, Chapter 5, Article E
"Landscaping and Tree Standards", 14-5E-6:
PRESERVATION OF EXISTING TREES, E, Table
5E-2 "Schedule of Substitution Values"
Tree planting requirements for the
removal of trees:
36" or > DBH* = 3 required trees
12-35" DBH = 2 required trees
2-12" DBH = 1 required tree
*DBH = diameter at breast height (4.5’)
Tree Risk
Management
City Code, Title 6, Chapter 1, 6-1-2: PUBLIC
NUISANCE DEFINED; PUBLIC NUISANCES
ENUMERATED, B. "Diseased Or Damaged
Trees Or Plant Materials"
Any dead, diseased, or damaged trees be
injurious to other trees, property, or
people should be managed appropriately.
Tree Protection
City Code, Title 18, Chapter 3, 18-3-2:
DESIGN STANDARDS, E: "Landscape
Preservation"
The landscape shall be preserved in its
natural state by minimizing tree and soil
removal. Structures and other site
improvements shall be located where the
maximum number of trees are preserved
on the site. Provides development plan
criteria which requires trees to be
preserved.
City Code, Title 14, Chapter 5, Article E
"Landscaping and Tree Standards", 14-5E-5:
PROTECTION AND MAINTENANCE, C
Explains the property owner’s [all types
except single-family] tree maintenance
and replacement responsibility.
City Code, Title 14, Chapter 5, Article E
"Landscaping and Tree Standards", 14-5E-6:
PRESERVATION OF EXISTING TREES, A-E
Describes tree root protection
requirements such as a minimum
protection zone extending to the tree’s
canopy drip line. Describes the role of the
city forester and that the preserved trees
must survive for at least five years or else
replacement is required.
City Code, Title 10, Chapter 8, 10-8-5:
DAMAGE TO TREES OR PLANT MATERIALS
PROHIBITED, A & B
Describes tree protection during
construction and the role of the city
forester.
Ordinance 05-4186, 12-15-2005 Street Tree
Requirements, and listed in City Code, Title
14, Chapter 5, Article E "Landscaping and
Tree Standards", 14-5E-7: STREET TREE
REQUIREMENTS
Provides minimum tree spacing, number,
and minimum planting site width for street
trees adjacent or within the public right-of-
way.
Invasive
Management
City Code, Title 14, Chapter 5, Article I
"Sensitive Lands and Features", 14-5I-6:
JURISDICTIONAL WETLANDS, F. "Design
Standards" 5 & 6
No planting of foreign or invasive species,
including intrusive native varieties, in
regulated wetland or buffer areas is
prohibited. – recommend a species list
Arborist
Standards
City Code, Title 10, Chapter 8, 10-8-10:
ARBORICULTURAL SPECIFICATIONS AND
STANDARDS OF PRACTICE
The city forester is authorized to establish
specific standards for tree planting and
maintenance.
Iowa City Urban Forest Management Plan | 10
Tree Pruning City Code, Title 10, Chapter 8, 10-8-7:
TRIMMING TREES AND PLANT MATERIALS
Describes the pedestrian and vehicle tree
clearance standards established by the city
forester.
Tree Nursery
Stock
Requirements
City Code, Title 14, Chapter 5, Article E
"Landscaping and Tree Standards", 14-5E-
7:STREET TREE REQUIREMENTS, B. "Street
Trees Within Public Right Of Way"
Any tree planted within the street right of
way must have a single trunk, with a
minimum of four feet (4') from grade to
the first branch, at the time of planting.
Minimum Soil
Volume
City Code, Title 14, Chapter 5, Article E
"Landscaping and Tree Standards", 14-5E-4:
TREE PLANTING REQUIREMENTS, C. "Siting
Requirements"
The minimum planting area required for
large trees is 256 square feet and 120
square feet for small trees.
Tree Species
List
City Code, Title 14, Chapter 5, Article E
"Landscaping and Tree Standards", 14-5E-3:
GENERAL REQUIREMENTS AND
MEASUREMENTS, A. "Permitted Species"
The city forester is to establish the list of
recommended trees for planting.
Related Plans & Initiatives
In addition to the tree and landscape preservation and enhancement listed in the City Code, trees and the entire
urban forest also have high importance in other City and region plans, studies, and initiatives. This incorporation
of trees and urban forests in these efforts displays the appreciated value considered by many organizations and
entities. The following describes these efforts at a high-level which were reviewed during the discovery phase
of the Urban Forest Sustainability & Management Audit.
Table 3. Existing efforts with urban forestry references presenting opportunity to integrate with the UFMP
Document Impacting the Urban Forest
IC2030: Comprehensive Plan
Update (2013)
- Goals for growth and proper land use
- Preserving and enhancing the environment and resources
- Goals and strategies for parks and open space use and connectivity
Gather Here Park Master Plan
(2017)
- Individual park plans for improving the service, availability and use
Natural Areas Master Plan (2018)
- Inventory and analysis of the City’s parks and natural areas
- Describes how to restore and manage these areas in order to
preserve their ecological functions and increase biodiversity (the
STAR Community)
South District Plan (2015) - Goals for tree-lined streets
- Goals for parks, trails, and open space
Climate Action and Adaption Plan
(in progress)
- Strategies to achieve emissions targets. An opportunity for this UFMP
to be integrated as trees play a major role in climate change mitigation
Others
- Complete Streets
- Sidewalk Infill Program
- Bicycle Master Plan
- Trails Master Plan
- Downtown Redevelopment Plan
- University Heights Community
- Johnson County conservation efforts
Iowa City Urban Forest Management Plan | 11
Other City Department Interaction
The many elements, challenges, and locations of trees managed by the City require cohesive management and
interactions among departments, divisions, and organizations to maintain and enhance it. To illustrate the
complexity of urban forest management, the following provides an example of some of the entities involved or
impacting trees to any extent. It shows that managing the urban forest cannot afford inward looking and requires
inclusiveness among the entire City.
Table 4. Departments and entities that impact urban forest management
Parks and Recreation Department
o Parks and Forestry Division
o Recreation Division
o Facilities Division
o Cemetery Division
➔ Parks and Recreation Foundation – the 501(c)3 that oversees the Endowment Fund
➔ Parks and Recreation Commission
Neighborhood and Development Services Department (NDS)
o Sustainability Services
o Neighborhood Services
▪ Urban Planning
▪ Neighborhood Outreach
• Neighborhood Council of Iowa City
• Program for Improving Neighborhoods (PIN) Grant
• 36 Neighborhood Associations
▪ Community Development
• UniverCity Neighborhood Partnership Program
▪ Metro Planning Organization of Johnson County (MPOJC) – Complete Street policy
and County Master Plan
➔ Neighborhood Open Space Program (between NDS and the Finance Department)
➔ City Attorney’s Office – involved with legal issues regarding urban forests
➔ City Managers Office and Communications Division
Public Works Department
o Engineering Division – oversees the Complete Streets Policy
o Streets and Traffic Engineering
o Wastewater/Water
o Transit
o Refuse/Recycling
➔ Planning and Zoning Commission
➔ Climate Action Steering Committee
➔ Board of Adjustment
Iowa City Urban Forest Management Plan | 12
Existing and Potential Partners in Urban Forestry
Beyond the City interactions there are opportunities and existing partnerships to grow the urban forest. Some
examples and their strengths and opportunities to bring to a partnership are provided below.
Table 5. Examples of potential partners in implementing strategies of the UFMP
Opportunity for Partnership and Support
Organization Grants Technical
Support
Training,
Education,
and
Resources
Advocacy Volunteer
Iowa Department of Natural Resources X X X
Iowa Urban Tree Council X X X
Trees Forever, Inc. X
University of Iowa and ISU Forestry
Extension X
Project Green X
Neighborhood Associations X
Iowa City Downtown District X
Iowa City Community School District X
MidAmerican Energy X
Volunteer Engagement & Public Education
Community support, education, and involvement are essential to an urban forestry program. The City is actively
pursuing enhancement of this with the 2016-2018 tree inventory and software, development of this Plan, Arbor
Day events for public and private schools with local media coverage, and by acquiring the Arbor Day Foundation’s
Tree City USA award annually since 1979. In 2018 the City was awarded the Tree City USA Growth Award. The
potential partnerships described above are opportunities for increasing public engagement and education. Also,
the tree inventory software application could be used by the community to learn about the trees around them,
the many benefits the trees provide, and areas planned for tree maintenance.
Arbor Day celebration in Iowa City, learn about the City’s trees on the app, and the Iowa City Planting in the Right-of-Way brochure
Iowa City Urban Forest Management Plan | 13
TREE AND PLANTING SITES INVENTORY SUMMARY
Using the inventory data in Microsoft Excel, Access, ArcGIS, and the City’s
Tree Plotter app, analyses were conducted to determine the state,
characteristics, and trends of the city-managed trees. The inventory does
not account for trees along stream corridors or undeveloped City
property.
The information is provided to guide future maintenance and
management and to better plan for the health and longevity of the City’s
urban forest.
This analysis and summary was conducted using the inventory data
completed in March of 2018 which, as of March, consisted of 45,014 trees
and 4,972 planting sites. Of those 45,014 trees, 25,451 are street trees
and 19,563 points are park trees. Planting sites were only mapped along
or within the City’s rights-of-way, not in parks. It should be noted that the
City is actively managing trees and updating the inventory database so
these counts and overall summaries may vary slightly.
Some of the analyses and summaries were completed separately for street
and park trees because of the differences in management techniques.
The following section provides the results of the analysis of the street and park tree inventory analysis by
structure and maintenance needs. This analysis informed the tree maintenance and overall resource strategies.
Iowa City’s tree inventory displayed in the City’s Tree Plotter software application
Tree inventory crew image source:
Plan-It Geo
Iowa City’s Tree Plotter app
www.pg-cloud.com/IowaCity
Iowa City Urban Forest Management Plan | 14
The Structure of City-Managed Trees
Urban forest structure describes the tree population in terms of its species composition, number of trees, age
classes, and tree distribution. These summaries assist urban forest managers in proper tree management and
planting to ensure long lasting canopy and benefits distributed equally across the City.
TREES BY LAND USE
Before summarizing trees by structure and maintenance needs, it is important to understand the distribution of
trees in relation to land use. The land use affects the type of maintenance needed or previously conducted; the
adjacent landowners and their views, perspectives, and willingness to assist; and the resources available for a
tree in a particular land use. The following chart describes the distribution of trees across land uses.
PARK TREE DISTRIBUTION
The City maintains trees approximately 50 parks. Based on the inventory, a total of 19,563 trees are in
maintained areas of parks and trails. This includes trees plotted as “stump”, “removed”, and “dead”. The
following provides a summary of the parks with the highest number of trees but a table of total trees by park is
provided in Appendix C.
Table 6. Parks with the highest tree count
Park Name Count % of Park Trees
Iowa river rc trail 1554 7.9%
Willow creek park 2355 12.0%
Hickory Hill park 2468 12.6%
Peninsula Park 2918 14.9%
Terry Trueblood Recreation Area 3605 18.4%
61%
31%
5%4%
0.1%0.2%
Figure 3. Land use distribution of inventoried trees
Park/ Vacant/ Other
Single Family
Small Commercial
Multi Family
Industrial/ Large
Commercial
N/A
Iowa City Urban Forest Management Plan | 15
TREE DIVERSITY AND COMPOSITION
Tree composition data are essential since the types of trees present in a community greatly affect the amount
of benefits produced, tree maintenance activities, and budgets. Based on the inventory data there exists a total
of 66 unique genera (includes “N/A”, “Conifer”, and “Broadleaf”) with the top five comprised of Acer (20%),
Fraxinus (8%), Quercus (8%), Ulmus (7%), Celtis (6%). The top ten genera comprise 72% (32,385) of the total
street and park tree population.
Table 7. Top 10 genera
Genus Count % Whole
Acer 8958 20%
Fraxinus 3527 8%
Quercus 3422 8%
Ulmus 3280 7%
Celtis 2903 6%
Morus 2804 6%
Malus 2666 6%
Prunus 2074 5%
Gleditsia 1688 4%
Thuja 1063 2%
Total 32385 72%
Based on the inventory data there exists a total of 178 unique tree species (includes generalized species
classifications such as “Ash” and “Birch”). The top ten species comprise 50% of the population, the highest
belonging to silver maple (8.1%), followed by northern hackberry (6.4%), and green ash (6.1%). The following
provides a summary of the top ten species identified in the 2016-2018 tree inventory.
Table 8. Top 10 species
Common Name Count
%
Whole
Silver maple 3650 8.1%
Northern hackberry 2903 6.4%
Green ash 2727 6.1%
Crabapple 2631 5.8%
Mulberry 2185 4.9%
American elm 1987 4.4%
Black cherry 1807 4.0%
Boxelder 1732 3.8%
Honeylocust 1688 3.7%
Norway maple 1189 2.6%
Total 22499 50%
The abundance of maple, particularly silver maple, pose present and future concerns. Large, maturing silver
maples tend to shed branches presenting a potential risk. Also, silver maples grow large and are often multi -
stemmed, resulting in high maintenance costs when overly mature or diseased silver maples require removal. It
is also always important to maintain species diversity at the street block and neighborhood level, which
maintains citywide tree diversity and pest/disease resiliency.
8.1%
6.4%
6.1%
5.8%
4.9%
4.4%
4.0%
3.8%
3.7%
2.6%
Figure 5. Top 10 tree species Silver maple
Northern hackberry
Green ash
Crabapple
Mulberry
American elm
Black cherry
Boxelder
Honeylocust
Norway maple
20%
8%
8%7%
6%
6%
6%
5%
4%2%
Figure 4. Top 10 tree genera Acer
Fraxinus
Quercus
Ulmus
Celtis
Morus
Malus
Prunus
Gleditsia
Thuja
Iowa City Urban Forest Management Plan | 16
SIZE AND AGE DISTRIBUTION
The distribution of tree ages influences the structure of the urban forest as well as the present and future costs.
An uneven-age urban forest offers continued flow of benefits and a more uniform workflow allowing managers
to more accurately allocate annual maintenance funds.
Figure # shows the distribution of size classes (DBH or diameter at breast height, 4.5’) for the inventoried trees
that were assigned a value. According to the figure, the 6-12in DBH range comprises the majority of the tree
inventory database with 14,372 trees or 32% and the 24-30in DBH range makes up the smallest portion with
3,019 trees or 7%, slightly less than the >30in range with 3,027 trees. Street trees average 13.1”, park trees with
11.1” and an overall average of 12.2” DBH.
According to Figure #, the aggregated data does not reflect the ideal urban forest distribution (McPherson,
Soares et al. 2011) due to the count of the 0-6in and 6-12in DBH ranges. Ideally, the 0-6in range would represent
40% of the population and the 6-12in range would represent 25% of the population. The distribution of individual
tree ages within a tree population influences present and future costs as well as the flow of benefits. An ideal
age/size distribution in the tree population allows managers to allocate annual maintenance costs uniformly
over many years and assures continuity in overall tree canopy coverage and associated benefits which are often
dependent on the growing space of individual trees (e.g. open grown versus restricted growing areas).
To optimize the value and benefit of trees, the community forest should have a high percentage of large canopy
trees which provide more ecosystem benefits. At the same time, there must be a sufficient number of younger,
smaller trees in the tree population to account for the loss of trees over time and thereby maintain a sustainable
community forest. In traditional forest management, this is similar to an uneven-aged stand or tree population.
The Management Needs of City-Managed Trees
Tree characteristics and outside forces affect the management needs for urban trees. An analysis of the
condition and maintenance requirements assists managers in planning the urban forest. Tree condition indicates
how well trees are managed and how well they perform given site-specific conditions. Tree maintenance needs
are inventoried for public safety reasons and for the health and longevity of the trees. Understanding the
maintenance needs assists tree managers in establishing daily work plans and has also complemented the
development of the Urban Forest Management Plan.
URBAN FOREST CONDITION
The inventory data was analyzed to identify trends in tree management needs and condition. Local information
on the condition of street and park trees plays an important role in community planning, municipal budge ting,
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
0-6in 6-12in 12-18in 18-24in 24-30in >30in
Figure 6. Iowa City's tree diameter distribution versus ideal distribution
City Distribution Ideal Distribution
27%
32%
17%
10%
7%7%
40%
25%
15%
10%
6%4%
Iowa City Urban Forest Management Plan | 17
and use of resources. Each inventoried tree was rated for the condition of the wood and the foliage on a scale
of “excellent”, “good”, “fair”, “poor”, and “critical/dead” using the inventory arborists’ expertise in tree species
physiology and responses to factors affecting each tree.
The tree health (condition) chart shows that of the 45,014 trees inventoried, the majority (47%) are in good
condition. 1,384 (3%) trees are critical or dead and 2,428 (5%) trees are in poor condition. Trees that are dead
or dying should be removed, with priority to remove the highest risks. Trees that are in poor condition should
be monitored, maintained, treated, and/or removed depending on each tree’s situation.
Figure 8 shows the condition of street versus park trees. As illustrated, street trees have a better overall
condition though there exists more critical or dead trees in parks. These summaries are addressed in the street
and park tree maintenance recommendations.
The top ten tree species comprise 50% of the total urban forest so the condition of these species needs to be
evaluated to determine their performance in an urban environment. The figure below summarizes the condition
distribution of each of the top ten species.
The evaluation of condition of the top ten species shows that the majority of trees are rated as either good or
fair condition.
47%
41%
5%
3%
2%0%
Figure 7. Condition of street and park trees
Good Fair
Poor Critical/Dead
Excellent N/A
0
2000
4000
6000
8000
10000
12000
14000
Figure 8. Comparison of the condition of street and park trees
Street Park
28%
49%
29%
62%
38%
55%
38%54%38%33%
51%
40%
42%
30%
53%
33%
50%
43%
47%57%
0%
50%
100%
Figure 9. Condition distribution among the top 10 species
% Excellent % Good % Fair % Poor % Critical/Dead
Iowa City Urban Forest Management Plan | 18
TREE OBSERVATIONS
Observations were noted during the inventory to
indicate common issues of the street and park
trees such as mechanical damage, cavity decay,
and improper mulching practices. A total of
39,311 observations were noted for 23,866
trees. The chart to the right summarizes the
observations for the 45,014 trees inventoried (as
of March 2018).
The trees noted with crown dieback (12,294 trees) should be monitored, especially the trees still in fair or good
condition to determine if additional decline can be prevented or reduced. Other observations such as mechanical
damage, poor structure, poor location, and improper installation/pruning/mulching may be a result of
anthropogenic causes. While some observations can be treated, many cannot be corrected and should instead
be prevented, such as mechanical damage and large girdling roots. These observations are useful in
understanding trends in maintenance practices, stress, and signs and symptoms of potential issues which help
to form the recommendations in this Plan.
4
27
57
126
132
270
373
638
705
741
755
773
871
2295
2332
2508
4866
9544
12294
0 5000 10000 15000
Grate/Guard
Memorial Tree
Remove Hardware
Improperly Mulched
Hardscape Damage
Improperly Pruned
Improperly Installed
Girdling Roots
Frost Cracks
Poor Location
Canker
Serious Decline
Poor Root System
Nutrient Deficiency
Mechanical Damage
Pests
Poor Structure
Cavity Decay
Crown Dieback
Figure 10. Count of tree observations
Mechanical damage to the trunk of a young tree
Improperly pruned tree
Source of images: Plan-It Geo
Iowa City Urban Forest Management Plan | 19
MAINTENANCE NEEDS OF STREET AND PARK TREES
The inventory included an assessment of the maintenance needs, if any, for each tree. This information along
with location, tree size, and the Tree Plotter application were used to guide the management recommendations.
The table and chart below provide a summary of the maintenance required for both street and park trees.
Table 9. Summary of maintenance needs for
street and park trees
Maintenance Need Count %
Removal 2110 5%
High Priority Pruning 532 1%
Immediate Priority Pruning 31 0.1%
Routine Pruning 32398 72%
Training Pruning 1501 3%
None Needed 8223 18%
NA 219 0.5%
Total Whole 45014 100%
Of the 45,014 total trees, 44,795 trees have a maintenance value. The majority of trees are noted for routine
pruning with 72%. Trees recommended for removal comprise 5% of the inventory with 2,110 trees and for high
priority pruning and immediate pruning, a total 532 (1%) and 31 (0.1%) trees, respectively, were noted.
The table to the right distinguishes the maintenance
needs of street and park trees separately since
maintenance methods are different for the two
areas. In summary, parks have more trees
recommended for removal with 1,173 trees but less
high priority and immediate priority pruning
compared to street trees. More street trees require
training pruning with a total of 1,262 trees.
Since the size of the tree often has a large impact on
cost, a summary of the trees for removal by DBH is
provided in the chart to the right. The 6-12in DBH
range has the highest percent with 36% (767 trees)
followed by the 3-6in range with 20% (425 trees)
and then 18-24in range with 19% (403 trees).
Table 10. Summary of maintenance need by street and park
Maintenance Need Street Park
Removal 937 1173
High Priority Pruning 381 144
Immediate Priority Pruning 23 8
Routine Pruning 16717 15576
Training Pruning 1262 239
None Needed 6047 2142
Total 25367 19282
5%
1%0%
72%
3%
18%
Figure 11. Maintenance needs summary
Removal
High Priority
Pruning
Immediate
Priority Pruning
Routine Pruning
Training Pruning
None Needed
3%
20%
36%
19%
12%
5%
5%
0%
Figure 12. Summary of street and park tree removals by DBH
0-3in
3-6in
6-12in
12-18in
18-24in
24-30in
>30in
N/A
Iowa City Urban Forest Management Plan | 20
SUMMARY OF TREE RISK ASSESSMENT
A Level 2 Qualitative Risk Assessment was completed during the 2016-2018 inventory for street and park trees
based on ANSI A300 (Part 9) standards and the protocols in the Best Management Practices : Tree Risk
Assessment, published by the International Society of Arboriculture (2011). Details about the risk assessment
process are found in Appendix B of this Plan.
Of the 45,014 trees in the inventory, 24,335 trees were assigned a risk rating. Primarily, a Low Risk Rating was
assigned with 22,859 trees (94%). Only 9 trees were assigned an Extreme Risk Rating, 5 of which are street trees.
It should be noted that these summaries of removals are as of March 2018. The City is actively managing tree
risk and these values may have changed.
Figure 14. Map of trees with a risk rating of Extreme
94%
5%
1%0.04%
Figure 13. Summary of the tree risk assessment for street and park trees
Low
Moderate
High
Extreme
Iowa City Urban Forest Management Plan | 21
INFRASTRUCTURE CONFLICTS
During the inventory, infrastructure conflicts with existing trees were noted. This information is useful for
maintenance crews when reviewing the inventory to determine tree limb clearance needs, potential issues with
trees damaging utilities, and to inform future planting efforts and replacement tree selection.
A total of 31,283 infrastructure conflicts were noted with the majority consisting of sidewalks (34%), vehicle
(33%), and pedestrian (30%). These percentages are based on the conflicts observed and not based on the total
number of trees. For example, a total of 10,550 conflicts with sidewalks were noted out of the total 31,281
conflicts observed inventory-wide. Many of these may not require immediate attention or ever cause issues
requiring maintenance but it is important to understand the types and distribution of infrastructure conflicts.
Common tree and infrastructure conflicts
From left to right: Tree and sidewalk damage (phillymag.com), tree and wire conflicts (newtownconservators.org), and
tree grate and sidewalk conflict (localecologist.org). Photos not taken in Iowa City.
8601
5835
2474
365
29 18 2 0
1732
4715
6759
30 107
449
93 74
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Vehicle Sidewalk Pedestrian Overhead
Utilities
Sign Other Fence Building
Figure 15. Summary of infrastructure conflicts with street and park trees
Street Park
Iowa City Urban Forest Management Plan | 22
Vulnerability to Emerald Ash Borer of City-Managed Trees
Emerald Ash Borer (Agrilus planipennis), also simply called EAB, is a small, metallic-green, invasive wood-boring
beetle native to east Asia that attacks and kills ash trees (Fraxinus spp.). Adult beetles live on the outside of trees
and feed on the leaves during the summer months, while the larvae feed on the living plant tissue, the phloem
and cambium, underneath the bark which ultimately kills the tree by disrupting the vascular system.
EAB was first found in Iowa City in 2014 and ash tree mortality is being noticed across the City, on public and
private property. The dying ash trees and removals has raised additional awareness and concern from the
general public. Since 2014, the City has been managing and addressing the impacts from EAB and has recently
identified trees to consider treating. Using the tree inventory data, the criteria for considering treatment for ash
trees includes ash trees between 9 inches and 35 inches in diameter, in good condition, and not conflicting with
utilities. City staff have identified a total of 400 trees that meet this criteria and are considering treatment.
Ongoing public outreach is underway and educational materials are being updated and provided to the public.
Learn more about EAB at https://www.icgov.org/emeraldashborer. Information about the City’s EAB response
guidelines, outreach methods, cost-share opportunities, and additional charts are found in Appendix H.
The following charts summarize the ash tree population within the City’s street and park inventory. These include
all trees with the common name ash, white ash, green ash, and black ash. Manchurian ash are not included in
the summaries as they are not susceptible to EAB and mountain ash is not a true ash (Sorbus genus, not Fraxinus).
The tree inventory software app should be used to prioritize EAB monitoring and management.
There are a total of 3,515 ash trees in the inventory database, of which 2,300
are street trees. The charts show that of the four ash species in the tree
inventory, 1,685 are in fair condition (of which 1,128 are street ash) followed
by 1,492 in good condition. 44 are in critical or dead condition and 271 are in
poor condition. The ash trees are primarily in the 6-12in DBH range with 984
trees (540 street ash) followed with 758 in the 12-18in range. Green ash have
the highest count (2,726) in the inventory compared to other ash species.
Figure 18. Key characteristics for ash
(Fraxinus) tree and emerald ash borer
(Agrilus planipennis) ID
Photo Source: www.csfs.colostate.edu
0
500
1000
1500
2000
Excellent Good Fair Poor Critical/Dead Not Specified
Figure 16. Condition classes of ash trees
Ash Black ash Green ash White ash
0
200
400
600
800
1000
1200
0-3in 3-6in 6-12in 12-18in 18-24in 24-30in >30in N/A
Figure 17. DBH distribution of ash trees
Ash Black ash Green ash White ash
Iowa City Urban Forest Management Plan | 23
Possible Planting Sites Summary
The 2016-2018 inventory also included the mapping of potential planting sites that meet the minimum spacing,
soil volume, proximity to utilities, etc. as defined by the City and listed in Appendix B. This was only completed
for sites adjacent or within the right-of-way. If a site met these parameters, the only information tracked was
the location and the qualitative size of the site; Proposed Site – Large, Proposed Site – Medium, and Proposed
Site-Small. There were a total of 3,274 Small Sites, 1,137 Medium Sites, and 562 Large Sites inventoried.
Discussion and recommendations for how to prioritize and use the location information is found in the goals and
strategies section. The location of these sites is in the map below or the link below provides a view of the active
map.
Figure 19. Location and size of planting sites (https://pg-cloud.com/IowaCity/?scenario=PlantingSites)
Examples of the types of planting sites inventoried shown in Google Street View
Iowa City Urban Forest Management Plan | 24
Criteria & Indicators
for Urban Forest Goals & Strategies
To provide the guidance for action to preserve and enhance Iowa City’s urban forest using the assessment of
the state of the urban forest
“What
Do We
Want?”
Iowa City Urban Forest Management Plan | 25
The following sections utilized the information and data that was analyzed and summarized to develop the
strategies in this Plan.
The following sections will provide the City with the methods for pursuing urban forest management goals and
measuring progress towards optimal levels of management. These optimal performance indicators are listed in
the tables below for the Vegetation Resource, Resource Management, Community Framework, and Institutional
Framework for Iowa City’s urban forest. The cells in the table that are in bold font and darker green/grey
represent the City’s current status. Using these Performance Indicators that follow and the methods for
monitoring (listed in the next section) will guide the City towards preserving and enhancing the urban forest
over a 20-year timespan. Following this section, a 5-year strategic plan is provided. The strategies are listed
within four goals and measures for monitoring achievement are provided in the Adaptive Management &
Monitoring section. This process allows the City to gauge progress towards optimal Performance Indicators
allowing for adaptive management and short-term strategies with long term impacts.
IOWA CITY’S 20-YEAR FRAMEWORK FOR URBAN FOREST MANAGEMENT
Criteria Table 11. Vegetation Resource – Performance Indicators Key Objective Low Moderate Good Optimal
V1
Tree species
diversity
Fewer than five
species dominate
the entire tree
population
citywide
No species
represents
more than 20%
of the entire tree
population citywide
No species
represents
more than
15% of the entire
tree population
citywide
No species
represent
more than
10% of the entire
tree population
citywide
Establish a diverse
and resilient tree
population citywide
V2
Diameter
distribution of
trees in the
City
1 of 6 DBH ranges
match the
McPherson Ideal
Distribution % (+/-
2%)
2 of 6 DBH ranges
match the
McPherson Ideal
Distribution % (+/-
2%)
4 of the 6 DBH
ranges match the
McPherson Ideal
Distribution % (+/-
2%)
6 of the 6 DBH
ranges match the
McPherson Ideal
Distribution % (+/-
2%)
Provide for uneven
aged
Distribution
citywide
V3
Street and
park tree
health
(includes pest
and disease)
Less than 30% of
trees rates as good
health condition
31 - 60% of trees
rated as good
health condition.
61 - 85% of trees
rated as good
health condition
Greater than 85%
of trees rated as
good health
condition
Healthy trees live
longer,
produce greater no.
of benefits
and reduce costs
associated
with maintenance
V4
Planting and
stocking levels
No planting of
street trees.
Abundant vacant
planting sites
10% of inventoried
planting sites are
planted (~500
trees)
50-75% of
inventoried planting
sites are planted
100% of inventoried
planting site are
planted (~2,500 –
3,750 trees)
Addition of trees ad
value, benefits and
improved function.
Based on ~5,000
planting sites along
within or adjacent
to street ROW
V5
Climate
change
resiliency
Less than 50% of
trees are of species
considered suitable
for Iowa City
50%-75% of trees
are of species
considered
suitable for Iowa
City
More than 75% of
trees are of species
considered suitable
for Iowa City
At least 90% of the
trees are of species
for Iowa City
Establish a tree
population
suitable for the
City’s urban
environment and
resilient to climate
change
Current State
Summary 0 3 1 1 Total: 5
Program & Data Analysis → Criteria and Performance Indicators → Measures → Goals & Strategies
Iowa City Urban Forest Management Plan | 26
Criteria Table 12. Resource Management – Performance Indicators Key Objective Low Moderate Good Optimal
R1
Urban forest
management
plan
Existing urban
forest management
plan limited in
scope and
implementation
Comprehensive
plan for publicly
owned and
managed urban
forest resources are
accepted and
implemented
Strategic multi-
tiered plan for
public and private
urban forest
resources is
accepted
and implemented
with adaptive
management
mechanisms
A comprehensive
urban forest
management plan
for private and
public property is
accepted and
implemented with
adaptive
management
mechanisms
A comprehensive
urban forest
management
plan for private and
public property is
integrated into
plans for
sustainability
R2
Citywide
funding
Funding for reactive
management
Consistent funding
for proactive
management
Consistent funding
to provide for net
increase in urban
forest benefits
Consistent private
and public funding
to sustain maximum
urban forest
benefits
Develop and
maintain adequate
and consistent
funding to
implement the
urban forest
management plan
R3
City urban
forestry
staffing
No training for
urban forestry staff
Certified arborist
on staff with regular
professional
development
Certified arborist
and professional
forester on staff
with regular
professional
development and
support staff
Multi-disciplinary
professional team
within the urban
forestry unit
Employ and train
adequate
Professional staff to
implement
citywide urban
forest management
plan
R4
Management
of publicly and
privately-
owned natural
areas
No information
about publicly or
privately owned
natural areas
Publicly and
privately owned
natural areas are
identified in a
generalized
“natural area
survey” or similar
document
Ecosystem structure
and function in
publicly
and privately-
owned natural
areas is
documented
The ecological
structure and
function of all
publicly owned and
privately-owned
natural areas are
documented and
used in making
management
decisions
Management
decisions are based
upon a detailed
understanding
of the ecological
structure and
function of all
publicly and
privately-owned
natural areas
R5
Urban forest
protection
policy
development
and
enforcement
No urban forest
protection policy
Policies in place to
protect public
portion of the
urban forest
Policies in place to
protect public and
private portions of
the urban forest
with enforcement
Integrated
municipal wide
policies that ensure
the protection of
the urban forest on
both public and
private land and are
consistently
enforced and
supported
The benefits derived
from the urban
forest are ensured
by the
implementation and
enforcement of the
urban forest
management
plan
R6
Urban forest
inventory
public-private
Sample-based
inventory of publicly
owned urban
forest
Complete inventory
of publicly owned
trees
Complete inventory
of publicly owned
trees and sample of
privately-owned
urban forest
Complete inventory
of the urban forest
resource
Complete inventory
of the urban forest
resource to direct
its management,
included age
distribution, species
mix, tree condition,
and assessment
Iowa City Urban Forest Management Plan | 27
Criteria Resource Management – Performance Indicators Key Objective Low Moderate Good Optimal
R7
Tree planting
and
establishment
on public and
private land
Tree planting and
establishment is
ad hoc
Tree establishment
is directed by needs
derived from a tree
inventory
Tree establishment
is directed by needs
derived from a tree
inventory and is
sufficient to meet
canopy cover
objectives
Tree planting and
establishment
program are driven
by the UFMP
objectives for
canopy cover,
species diversity,
and species
distribution
objectives to ensure
urban forest
sustainability
Tree planting and
establishment is
directed
by objective
criteria set in the
urban forest
management plan
R8
High risk tree
maintenance
Highest priority
removals only are
addressed within 5
years of notice
All high priority
removals and some
immediate pruning
is addressed within
2 years of notice
All high priority
removals and most
immediate pruning
is addressed within
2 months of notice
Proactive mature
tree care (lightning
protection, cabling,
etc.) is conducted
and risk is greatly
reduced except
after storm events
Maintain public
safety and the
longevity of the
trees and the
reputation of the
urban forest
program
R9
Public tree
condition
assessment
and
abatement
citywide
The condition of
the urban forest is
unknown
No citywide public
tree condition
assessment/
remediation
program.
Request
based/reactive
system
Complete public
tree inventory
including tree risk
information.
Request-based/
reactive risk
abatement
program system.
Use of work order
software
Inventory of public
trees includes
detailed tree risk
ratings; risk
abatement program
is in effect
eliminating
hazards using a
work order software
All publicly
managed
trees are free of
recognizable
hazards
R10
Routine tree
pruning
One-tenth of large
trees are pruned on
a 5-year rotation
(~650 trees per
year)
One-eighth of large
trees are pruned on
a 5-year rotation
(~820 trees per
year)
One-fifth of large
trees are pruned on
a 5-year rotation
(~1,300 trees per
year)
One-third of large
trees are pruned on
a 5-year rotation
(~2,170 trees per
year)
Improve tree
health, longevity,
public safety, and
clearance conflicts.
Based on ~32,600
trees >6” DBH
R11
Young tree
maintenance
No young tree
training
One-fifth of small
trees are training
pruned (~500 trees).
Newly planted trees
are training pruned
within 10 years of
planting
One-third of small
trees are training
pruned (~820
trees). Newly
planted trees are
training pruned at
3-4 years of
planting
One-half of small
trees are training
pruned (~1,235
trees). Newly
planted trees are
training pruned at 3
years of planting
Improve the
structure trees at an
early age to reduce
future maintenance
costs and issues.
Based on ~12,350
trees <6” DBH
Iowa City Urban Forest Management Plan | 28
Criteria Resource Management – Performance Indicators Key Objective Low Moderate Good Optimal
R12
Ash tree
management
No ash tree
management for
EAB is in place
An inventory of ash
trees and the
locations is current
Ash tree
management plan
in place
Ash tree
management plan is
in implementation
Plan and manage
ash trees to reduce
sudden widespread
mortality
R13
Tree site
suitability
Tree species are
considered in
planting
site selection
Guidelines are in
place for the
selection of suitable
species to meet
specific site criteria.
Best practices and
industry standards
are in place
Public trees are
planted in sites with
adequate soil
quality and
quantity, and
growing space to
achieve their
growth and form
potential. Private
owners are
provided science-
based standards on
tree selection and
site suitability
All trees are planted
in sites that will
maximize current
and future benefits
Management of
urban forest will
become more
efficient and
effective in
producing
environmental,
social and economic
benefits
R14
Invasive plant
species
management
Recognition of
invasive species
Recognition of
invasive species,
are actively
discouraged
and voluntary
control on private
and public lands
Invasive species are
recognized,
managed, and their
use is prohibited
Invasive plant
species
management plans
are developed and
implemented
for public and
private lands
Elimination of
invasive plant
species
R15
Public tree
condition
assessment
and
abatement
along
emergency
and
evacuation
routes
The condition of
trees along
emergency
evacuation
routes is unknown
No tree condition
assessment/
remediation
program along
emergency routes.
Request
based/reactive
system
Sample-based tree
inventory including
general tree risk
information along
emergency/
evacuation routes.
Risk abatement is
not systematic
Complete tree
inventory
which includes
detailed tree failure
risk ratings; risk
abatement
program is in effect
eliminating hazards
along emergency/
evacuation routes
Emergency and
evacuation routes
will be clear during
the on-set of storms
and will require
minimal clearing
of woody debris
following a storm
event
R16
Canopy
assessment
and canopy
goals
No canopy
assessment or a
low-resolution
canopy assessment
(e.g. i-Canopy) is
completed but no
goals are set
High-resolution
canopy assessment
is completed but no
goals are set
High-resolution
canopy assessment
and goals are
completed and the
existing canopy
cover equals 25-
50% of the goal
High-resolution
canopy assessment
and goals are
completed and the
existing canopy
cover equals 50-
75% of the goal
Understand canopy
cover distribution
citywide and set
goals to increase
canopy
R17
Tree
preservation
best practices
No standards or
best practices in
place
Standards in place
but outdated and
little adherence and
enforcement
Standards and best
practices are in
place and city
forester is
contacted to
oversee site plan.
City forester is
included in the
design, placement,
and construction or
repair of structures
and utilities
Street trees near
any excavation,
demolition, or
construction of any
building, structure,
or utility are
preserved or
protected
Current State
Summary 2 5 7 3 Total: 17
Iowa City Urban Forest Management Plan | 29
Criteria Table 13. Community Framework – Performance Indicators Key Objective Low Moderate Good Optimal
C1
General
awareness of
the urban
forest as a
community
resource
Urban forest seen
as a community
problem
Urban forest seen
as important to
the community
Urban forest
acknowledged as
providing
environmental,
social, and
economical services
Urban forest
recognized
as vital to the
community’s
environmental,
social and economic
well being
The general public
understands the
importance of the
urban forest to the
community
C2
Neighborhood
cooperation
Majority of
neighborhoods
Are unfamiliar with
Urban Forest
Management Plan
Isolated or limited
number of active
neighborhood
groups
Majority of
neighborhood
associations
form partnerships
with city
government to
implement the
UFMP
All neighborhoods
associations form
partnerships with
city government to
implement the
UFMP
At the
neighborhood level,
citizens understand
and cooperate
in urban forest
management
C3
Citizen,
municipal,
business,
commuter
interaction
No interaction
among
constituencies
Some interaction
among
constituencies,
with conflicting
goals
Informal and/or
general cooperation
Formal interaction
with staff
coordination
All constituencies in
the community
interact for the
benefit from the
urban forest
C4
Support by
private land
holders
Unfamiliar with
issues
Educational
materials and
advice available to
landholders
Clear goals for tree
resources by
landholders.
Incentives for
protection and
management of
private trees
Landholders
develop
comprehensive
tree management
plans (including
funding)
Private landholders
embrace citywide
goals and objectives
of the UFMP
Current State
Summary 1 2 1 0 Total: 4
Iowa City Urban Forest Management Plan | 30
Criteria Table 14. Institutional Framework – Performance Indicators Key Objective Low Moderate Good Optimal
I1
City public
agency
cooperation
Conflicting
processes among
departments and or
agencies that are
inconsistent with
the urban forest
management
Urban forest
management
processes are held
in common but
improvement in
cooperation among
departments and/
or agencies is
needed
Departments and/
or agencies are
functioning and
implementing
processes
consistent with the
UFMP on a project
specific basis
Municipal standards
in place for
implementing the
UFMP by
interdepartmental/
Interagency
processes on all
municipal projects
Ensure all city
departments
cooperate with
goals and objectives
of the UFMP
I2
Design and
development
industry and
other
government
agency
cooperation
Unfamiliar with
issues
Recognition and
acceptance of
issues
Implement design
and construction
objectives
consistent with the
UFMP
Implement design
and construction
objectives that
exceed UFMP
objectives and
support citywide
green infrastructure
Design and
development
industries, and
other government
agencies embrace
citywide UFMP
goals and objectives
I3
Landscape
and
arboriculture
industry
cooperation
No cooperation
among segments of
the green industry.
No adherence to
professional
standards and
ethics
General
cooperation among
nurseries, tree care
companies, etc.
Specific cooperative
arrangements with
City
Shared vision and
goals including the
use of professional
standards and
ethics
The landscape and
arboriculture
industries operate
with high
professional
standards and
ethics, and commits
to citywide urban
forest management
plan goals and
objectives
I4
Cooperation
within the
geographic
region
Government and
planning agencies
operate
independently
Government and
planning agencies
share similar policy
vehicles
Regional planning
is in effect
Regional natural
resource
comprehensive
planning is
coordinated
Cooperation and
interaction among
neighboring
regional planning
agencies and
governments
to support forest
sustainability
throughout the
region
Current State
Summary 0 4 0 0 Total: 4
Iowa City Urban Forest Management Plan | 31
Adaptive Management
& Monitoring
A management process to promote flexible decision making that can be adjusted in the face of uncertainties
“How Do We Get
What We Want?
& Are We Getting
What We Want?”
Iowa City Urban Forest Management Plan | 32
ADAPTIVE MANAGEMENT
Adaptive Management is a scientific approach to an urban forest management decision process. It promotes
flexible decision-making that can be adjusted in the face of uncertainties as outcomes from management actions
and other events become better understood. Careful monitoring of these outcomes both advances scientific
understanding and helps adjust policies or operations as part of an iterative learning process. Adaptive
management does not represent an end in itself, but rather a means to more effective decisions and enhanced
benefits. Its true measure is in how well it helps meet environmental, social, and economic goals; increases
scientific knowledge; and reduces tensions among stakeholders.
Figure 20: The management plan implementation process
20-Year Strategic Plan
5-Year
Management
Plan #1
5-Year
Management
Plan #2
5-Year
Management
Plan #3
5-Year
Management
Plan #4
Using an adaptive management approach will require the consistent monitoring of all the City’s criteria for urban
forest sustainability. The City will be able to judge if its new approaches to urban forest conservation are being
effective, develop relationships between management actions and outcomes, and identify significant trends.
This will allow the City to adjust management actions over time as changes occur both in the physical/biological
environment and in the expectations of the City’s residents.
The City can use the Urban Forest Sustainability & Management Audit that was provided as part of the UFMP
project to evaluate each element to identify shortcomings and opportunities. View Appendix B for an overview.
Few activities suggested by this strategic plan are as important to the success of urban forest management as
monitoring, but this step is often overlooked, poorly designed, and often underfunded by most cities. Monitoring
the City’s natural resources is a process very similar to those already developed for business. The basic
applications have already been developed, and there is little reason to reinvent the processes. This design for
the monitoring program incorporates the principles of sampling design theory and experimental design. Careful
consideration has been paid to the selection of indicators.
TYPES OF MONITORING
Monitoring here refers to the periodic and systematic measurement of observations of process or object. The
City should institute three forms of monitoring in association with the Management Plan: implementation,
effectiveness, and validation.
1. The implementation monitoring will determine if the Plan is being implemented as designed. It asks,
“Did we do what we set out to do?”
2. Effectiveness monitoring determines if the action achieved the stated goal or objective. It asks, “Did it
work?”
3. Validation monitoring determines if assumptions and models being used are valid and effective.
Annual Operating Plans
Strategies
Criteria and Performance Indicators Increasing detail Program & Analysis → Criteria and Performance Indicators → Measures → Goals & Strategies
The Process:
Criteria and performance indicators
identify 5-year management strategies
which inform annual operating plans.
The 5-year management plans allow for
an adaptive approach as the City strives
to achieve optimal levels of urban
forest management and sustainability.
Iowa City Urban Forest Management Plan | 33
Implementation Monitoring
The Parks and Forestry Division should review, on a semi-annual basis the implementation of the 5-year
Management Plan’s Strategies. There should be a stakeholder session to discuss accomplishments and
recommend strategies for accomplishing the scheduled objectives. Each year these stakeholders should jointly
publish a report to be distributed to the Mayor, City Council, Department Directors, and communities.
Effectiveness Monitoring
The 2016-2018 street and park tree inventory serves as the beginning of the effectiveness-monitoring program.
Information from Urban Forest Analysis presented in this Plan describes the present state of the urban forest.
The use of the criteria and key objectives allow the City to better understand and correlate the effectiveness of
its urban forest management practices and policies to reaching specific outcomes using the tree inventory
analysis.
Effectiveness monitoring should be conducted every 5 years.
Validation Monitoring
The City should maintain and update the tree inventory on a regular basis. This information will be used for the
City to conduct a 5-year analysis of the tree structure, maintenance needs, and potential risks, similarly to how
it was completed for this Management Plan.
RECOMMENDED METHODS FOR MONITORING PERFORMANCE CRITERIA
In the Criteria and Performance Indicators section, the table has a column “Criteria”. Each row has a criterion
with a reference number (i.e. V1 = 1st Criteria in the Vegetation Resource section). These reference numbers are
listed for each Strategy and a Criteria Key is provided below for reference.
Criteria Key
V1: Tree species diversity
V2: Diameter distribution of trees
in the City
V3: street and park tree health
V4: Planting and stocking levels
V5: Climate change resiliency
R1: Urban forest management plan
R2: Citywide funding
R3: City urban forestry staffing
R4: Management of publicly and
privately owned natural areas
R5: Urban forest protection policy
development and enforcement
R6: Urban forest inventory public-
private
R7: Tree planting and
establishment on public and
private land
R8: High risk tree maintenance
R9: Public tree condition
assessment and abatement
citywide
R10: Routine tree pruning
R11: Young tree maintenance
R12: Ash tree management
R13: Tree site suitability
R14: Invasive plant species
management
R15: Public tree condition
assessment and abatement
along emergency and
evacuation routes
R16: Canopy assessment and
canopy goals
R17: Tree preservation best
practices
C1: General awareness of the urban
forest as a community resource
C2: Neighborhood cooperation
C3: Citizen, municipal, business,
commuter interaction
C4: Support by private land holders
I1: City public agency cooperation
I2: Design and development
industry and other government
agency cooperation
I3: landscape and arboriculture
industry cooperation
I4: Cooperation within the
geographic region
Iowa City Urban Forest Management Plan | 34
Vegetation Resource
V1) Tree species diversity
Measure: Tree inventory data in Tree Plotter and/or MS Excel or Access
V2) Diameter distribution of trees in the City
Measure: Tree inventory data in Tree Plotter and/or MS Excel or Access
V3) Street and park tree health
Measure: Tree inventory data in Tree Plotter and/or MS Excel or Access
V4) Planting and stocking levels
Measure: Tree inventory data in Tree Plotter and/or MS Excel or Access
V5) Climate change resiliency
Measure: NOAA climate zones and the tree inventory data in Tree Plotter and/or MS Excel or Access
Resource Management
R1) Urban forest management plan (acceptance and implementation)
Measure: review by the Parks and Forestry Division
R2) Citywide funding
Measure: annual review by the Parks and Forestry Division
R3) City urban forestry staff funding
Measure: annual review by the Parks and Forestry Division
R4) Management of publicly and privately-owned natural areas
Measure: annual internal review of public land management to include random sampling of resources
and utilize the 2018 Natural Areas Master Plan and other plans/studies
R5) Urban forest protection policy development and enforcement
Measure: semi-annual review of process by Parks and Forestry and review of street and park tree
inventory data in tree management software relating to tree condition, observations, conflicts, etc.
R6) Urban forest inventory public-private
Measure: semi-annual review of process by Parks and Forestry and review the street and park tree
inventory data in tree management software and future inventory data
R7) Tree planting and establishment on public and private land
Measure: Review of the street and park tree inventory data and future tree inventories and analysis
R8) High risk tree maintenance
Measure: Internal review by Parks and Forestry by field sampling and reviewing data in tree and work
order management software to determine degree of risk abatement and reduction annually
R9) Public tree condition assessment and abatement citywide
Measure: Internal review by Parks and Forestry by field sampling and reviewing data in tree and work
order management software to determine degree of risk abatement and reduction annually
R10) Routine tree pruning
Measure: Internal review by Parks and Forestry by field sampling and reviewing data in tree and work
order management software to determine degree of risk abatement and reduction annually
R11) Young tree maintenance
Iowa City Urban Forest Management Plan | 35
Measure: Internal review by Parks and Forestry by field sampling and reviewing data in tree and work
order management software to determine degree of risk abatement and reduction annually
R12) Ash tree management
Measure: Internal review by Parks and Forestry by field sampling and reviewing data in tree and work
order management software to determine degree of risk abatement and reduction annually
R13) Tree site suitability
Measure: Internal review by Parks and Forestry by field sampling and reviewing data in tree and work
order management software to determine degree of risk abatement and reduction annually
R14) Invasive plant species management
Measure: Internal review of public and private lands using random sampling
R15) Public tree condition assessment and abatement along emergency and evacuation routes
Measure: Internal review by Parks and Forestry by field sampling and reviewing data in tree and work
order management software to determine degree of risk abatement and reduction annually
R16) Canopy assessment and goals
Measure: Canopy will be measured citywide and by neighborhoods and other geographic boundaries
and canopy goals will be set based on existing and future tree planting efforts and criteria in this Plan
R17) Tree preservation best practices
Measure: City forester is on site for review of construction/repair of structures and utilities that may
impact the trees within the right-of-way. Sample inventory and future inventories to see if in effect.
Community Framework
C1) General awareness of the urban forest as a community resource
Measure: Conduct a 5-year community survey
C2) Neighborhood cooperation
Measure: Conduct a 5-year community survey
C3) Citizen, municipal, business, commuter, interaction
Measure: Semi-annual review by Parks and Forestry
C4) Support by private land holders
Measure: Semi-annual review by Parks and Forestry
Institutional Framework
I1) City public agency cooperation
Measure: Semi-annual review by Parks and Forestry
I2) Design and development industry and other government agency cooperation
Measure: Annual random sampling of site specific designs and implementation of future tree inventories
I3) Landscape and arboriculture industry cooperation
Measure: The green industry use of ANSI standards, state BMP’s, state nursery grades and standards
I4) Cooperation within the geographic region
Measure: Semi-annual review by Parks and Forestry
Iowa City Urban Forest Management Plan | 36
First 5-Year Urban Forest
Management Plan Strategies
Strategies for advancing the urban forest by topic areas and the criteria and performance indicators
“How Do
We Get
What We Want?”
Iowa City Urban Forest Management Plan | 37
Once the Criteria and Performance Indicators were
identified for the Vegetation Resource, Resource
Management, Community Framework, and Institutional
Framework, a series of Monitoring Criteria were
developed to gauge progress towards optimal levels of
urban forest management and sustainability.
The first 5-year management plan represents the initial
action needed to lay the foundation for comprehensive
urban forest management. Strategies for
implementation in the first 5-year Urban Forest
Management Plan were chosen so that there was very
minimal requirement for any net increases in
operational or capital costs. These strategies have to do
with the processes, procedures, ordinances, and
education to support the institutional, community, and
technical capacities needed to move the management of
the urban forest forward.
Goals and Strategies for the first 5-Year Urban Forest
Management Implementation are arranged by category.
Each action is preceded by the year in which it is
intended to be initiated or completed. The specific
criteria addressed by each action are then listed (see the Criteria and Performance Indicators tables). Finally, the
responsible or lead City agency is indicated.
The following pages describe how each Goal and Strategy impacts the City’s placement on the Urban Forest
Criteria and Performance Indicator Spectrum. The number of Criteria and Performance Indicators affected by
the Goals and Strategies reflects the efficiency of these actions. Use this as a guide to share the importance of
each strategy and to determine which measure and milestone should be utilized to assess progress.
Program & Data Analysis → Criteria and Performance Indicators → Measures → Goals & Strategies
Assessments and planning lead to improved maintenance, community interaction, and city tree canopy
Image sources: Plan-It Geo photo stock
Iowa City Urban Forest Management Plan | 38
IOWA CITY’S URBAN FOREST GOALS & STRATEGIES AND THE IMPACT ON THE
CRITERIA & PERFORMANCE INDICATORS
(V=Vegetation Resource, R=Resource Management, C=Community Framework, I=Institutional Framework)
EDUCATION
Goal One: Promote proper tree care through education and enforcement (Table 15)
G1-1
Year 1: Update the Planting in the Right-of-Way
brochure or create a new brochure that informs and
educates residents and City staff about the UFMP, the
benefits of trees, and proper tree care.
Criteria:
• V – 1, 2, 3, 4, 5
• R – 1, 4, 5, 7, 11, 13, 14, 16
• C – 1, 2, 3, 4
• I – 1, 2, 3, 4
Responsible Agency: Forestry and Parks, Communications
G1-2
Year 1: Prepare and implement a Neighborhood Tree
Stewardship program to educate residents on tree care
and the urban forest. Utilize neighborhood associations
and other partners described in the UFMP.
Criteria:
• V – 1, 2, 3, 4, 5
• R – 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16
• C – 1, 2, 3, 4
• I – 1, 2, 3, 4
Responsible Agency: Forestry and Parks, Neighborhood
Development Services, Communications
G1-3
Year 1: Update and maintain the City’s urban forestry
webpage to include information about the UFMP and
results of the inventory and program analysis for City
residents. Include the Tree Plotter link and promote on
social media.
Criteria:
• V – 1, 2, 3, 4, 5
• R – 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16
• C – 1, 2, 3, 4
• I – 1, 2, 3, 4
Responsible Department: Forestry and Parks,
Neighborhood Development Services, Communications
Criteria Key
V1: Tree species diversity
V2: Diameter distribution of trees in the City
V3: street and park tree health
V4: Planting and stocking levels
V5: Climate change resiliency
R1: Urban forest management plan
R2: Citywide funding
R3: City urban forestry staffing
R4: Management of publicly and privately
owned natural areas
R5: Urban forest protection policy development
and enforcement
R6: Urban forest inventory public-private
R7: Tree planting and establishment on public
and private land
R8: High risk tree maintenance
R9: Public tree condition assessment and
abatement citywide
R10: Routine tree pruning
R11: Young tree maintenance
R12: Ash tree management
R13: Tree site suitability
R14: Invasive plant species management
R15: Public tree condition assessment and
abatement along emergency and
evacuation routes
R16: Canopy assessment and canopy goals
R17: Tree preservation best practices
C1: General awareness of the urban forest as a
community resource
C2: Neighborhood cooperation
C3: Citizen, municipal, business, commuter
interaction
C4: Support by private land holders
I1: City public agency cooperation
I2: Design and development industry and other
government agency cooperation
I3: landscape and arboriculture industry
cooperation
I4: Cooperation within the geographic region
Iowa City Urban Forest Management Plan | 39
G1-4
Year 1: Provide and maintain a current list of qualified
and certified ISA or ASCA arborists working in the City.
Criteria:
• V – 1, 2, 3, 4, 5
• R – 4, 5, 7, 8, 9 10, 11, 12, 13, 14, 15, 16
• C – 2, 3, 4
• I – 2, 3, 4
Responsible Agency: Forestry and Parks, Communications
G1-5
Year 2: Inspect and monitor ash trees for signs and
symptoms of EAB. Prioritize removal of ash trees in poor
and critical condition. Develop an EAB management plan.
Criteria:
• V – 3
Responsible Agency: Forestry and Parks
G1-6
Year 3: In partnership with the University and other
entities, conduct training programs on inventory and
management of natural areas for public and private
property owners.
Criteria:
• R – 4, 6, 12, 14
• C – 4
Responsible Agency: Forestry and Parks, Communications,
Program Partners
G1-7
Year 5: Form a committee of public and private natural
resource professionals to review and revise the Tree
Species List every five years.
Criteria:
• V – 5
Responsible Agency: Forestry and Parks
Criteria Key
V1: Tree species diversity
V2: Diameter distribution of trees in the City
V3: street and park tree health
V4: Planting and stocking levels
V5: Climate change resiliency
R1: Urban forest management plan
R2: Citywide funding
R3: City urban forestry staffing
R4: Management of publicly and privately
owned natural areas
R5: Urban forest protection policy development
and enforcement
R6: Urban forest inventory public-private
R7: Tree planting and establishment on public
and private land
R8: High risk tree maintenance
R9: Public tree condition assessment and
abatement citywide
R10: Routine tree pruning
R11: Young tree maintenance
R12: Ash tree management
R13: Tree site suitability
R14: Invasive plant species management
R15: Public tree condition assessment and
abatement along emergency and
evacuation routes
R16: Canopy assessment and canopy goals
R17: Tree preservation best practices
C1: General awareness of the urban forest as a
community resource
C2: Neighborhood cooperation
C3: Citizen, municipal, business, commuter
interaction
C4: Support by private land holders
I1: City public agency cooperation
I2: Design and development industry and other
government agency cooperation
I3: landscape and arboriculture industry
cooperation
I4: Cooperation within the geographic region
Iowa City Urban Forest Management Plan | 40
ORGANIZATION & MANAGEMENT
Goal Two: Improve efficiencies and collaborate to propel urban forest management (Table 16)
G2-1
Year 1: Utilize the tree inventory and work order
management software to keep data current and improve
work efficiencies. Use the system to monitor progress
towards optimal Vegetation Resource Performance
Indicators.
Criteria:
• R – 6, 9
Responsible Agency: Forestry and Parks
G2-2
Year 1: Provide training of the GIS section, tree
maintenance crews, and other staff on the utilization of
the citywide urban forest inventory in the tree
management software.
Criteria:
• R – 5, 17
• I – 1, 2, 3
Responsible Agency: Forestry and Parks, Neighborhood
and Development Services
G2-3
Year 1: Review and update arborist standards and best
practices, including tree protection and preservation
during construction/repair of structures and utilities
within the right-of-way. Create a document that
describes these and share with other personnel
responsible for overseeing design and development and
tree care. See Appendix D for an example of Best
Practices for Tree Preservation.
Criteria:
• I – 1, 3
Responsible Agency: Forestry and Parks
G2-4
Year 1: Create a system of review and risk assessment of
street, park, and public space trees that is directly tied to
the work order system. Ensure all staff understand the
workflow to maintain a current and accurate database of
the condition and maintenance needs of trees that is
tracked in the inventory software. Track all new plantings
in the software as well.
Criteria:
• R – 6, 8, 9, 15
• I – 1
Responsible Agency: Forestry and Parks
Criteria Key
V1: Tree species diversity
V2: Diameter distribution of trees in the City
V3: street and park tree health
V4: Planting and stocking levels
V5: Climate change resiliency
R1: Urban forest management plan
R2: Citywide funding
R3: City urban forestry staffing
R4: Management of publicly and privately
owned natural areas
R5: Urban forest protection policy development
and enforcement
R6: Urban forest inventory public-private
R7: Tree planting and establishment on public
and private land
R8: High risk tree maintenance
R9: Public tree condition assessment and
abatement citywide
R10: Routine tree pruning
R11: Young tree maintenance
R12: Ash tree management
R13: Tree site suitability
R14: Invasive plant species management
R15: Public tree condition assessment and
abatement along emergency and
evacuation routes
R16: Canopy assessment and canopy goals
R17: Tree preservation best practices
C1: General awareness of the urban forest as a
community resource
C2: Neighborhood cooperation
C3: Citizen, municipal, business, commuter
interaction
C4: Support by private land holders
I1: City public agency cooperation
I2: Design and development industry and other
government agency cooperation
I3: landscape and arboriculture industry
cooperation
I4: Cooperation within the geographic region
Iowa City Urban Forest Management Plan | 41
G2-5
Year 2: Encourage and support the Parks and Recreation
Commission to create an Urban Forestry sub-board.
Criteria:
• R – 1, 2, 5
• I – 1, 2
Responsible Agency: Forestry and Parks, Parks and
Recreation Commission
G2-6
Year 1: Present the UFMP to potential partners such as
Trees Forever, Inc., University of Iowa, Project Green,
Downtown District, Community School District, and
Neighborhood Associations to explore partnership
opportunities.
Criteria:
• C – 1, 2
• I – 4
Responsible Agency: Forestry and Parks, Parks and
Recreation Commission
G2-7
Year 3: Conduct a high-resolution urban tree canopy
assessment citywide and by planning boundary such as
neighborhoods. At minimum, conduct an i-Tree Canopy
assessment as an initial study.
Criteria:
• R – 16
Responsible Agency: Forestry and Parks, Planning
G2-8
Year 5: Create an updated Tree Species List and require
the use of only these species on all tree planting projects
required through code or through use of public funds.
Criteria:
• V – 1, 5
• R – 7
Responsible Agency: Forestry and Parks, Communications
Criteria Key
V1: Tree species diversity
V2: Diameter distribution of trees in the City
V3: street and park tree health
V4: Planting and stocking levels
V5: Climate change resiliency
R1: Urban forest management plan
R2: Citywide funding
R3: City urban forestry staffing
R4: Management of publicly and privately
owned natural areas
R5: Urban forest protection policy development
and enforcement
R6: Urban forest inventory public-private
R7: Tree planting and establishment on public
and private land
R8: High risk tree maintenance
R9: Public tree condition assessment and
abatement citywide
R10: Routine tree pruning
R11: Young tree maintenance
R12: Ash tree management
R13: Tree site suitability
R14: Invasive plant species management
R15: Public tree condition assessment and
abatement along emergency and
evacuation routes
R16: Canopy assessment and canopy goals
R17: Tree preservation best practices
C1: General awareness of the urban forest as a
community resource
C2: Neighborhood cooperation
C3: Citizen, municipal, business, commuter
interaction
C4: Support by private land holders
I1: City public agency cooperation
I2: Design and development industry and other
government agency cooperation
I3: landscape and arboriculture industry
cooperation
I4: Cooperation within the geographic region
Iowa City Urban Forest Management Plan | 42
PLAN IMPLEMENTATION
Goal Three: Build the team and the reinforcements to implement the Plan (Table 17)
G3-1
Year 1: Coordinate a presentation and delivery of the
Executive Summary to the Mayor for the consideration
that directs all City agencies to actively cooperate in the
implementation of the UFMP.
Criteria:
• This strategy supports all criteria and
implementation of adaptive management
process.
Responsible Agency: Forestry and Parks
G3-2
Year 1: Prepare a draft resolution, for City Council
consideration, that recognizes the UFMP as the strategic
plan for the management of the urban forest in the City.
Criteria:
• This strategy supports all criteria
Responsible Agency: Forestry and Parks
G3-3
Year 1: Establish an Internal Technical Advisory
Committee, comprised of appointed departmental
representatives. The committee will meet quarterly to
review progress, as part of the adaptive management
strategy, identify issues and make recommendations
associated with the implementation of the UFMP.
Criteria:
• This strategy supports all criteria
Responsible Agency: Forestry and Parks
G3-4
Year 2: Prepare a Land Development Regulation that
requires adherence to ANSI Tree, Shrub, and other wood
Plant Maintenance (A300 series).
Criteria:
• I – 3
Responsible Agency: Forestry and Parks
G3-5
Year 3: Incorporate the criteria and key objectives of the
UFMP into the IC2030 Comprehensive Plan, Natural Areas
Master Plan, and the Climate Action and Adaption Plan
where feasible. At minimum, attend meetings in regard
to these plans in order to discuss integrations and where
these plans and the UFMP complement one another.
Criteria:
• Institutional Framework – 1
Responsible Agency: Forestry and Parks
Criteria Key
V1: Tree species diversity
V2: Diameter distribution of trees in the City
V3: street and park tree health
V4: Planting and stocking levels
V5: Climate change resiliency
R1: Urban forest management plan
R2: Citywide funding
R3: City urban forestry staffing
R4: Management of publicly and privately
owned natural areas
R5: Urban forest protection policy development
and enforcement
R6: Urban forest inventory public-private
R7: Tree planting and establishment on public
and private land
R8: High risk tree maintenance
R9: Public tree condition assessment and
abatement citywide
R10: Routine tree pruning
R11: Young tree maintenance
R12: Ash tree management
R13: Tree site suitability
R14: Invasive plant species management
R15: Public tree condition assessment and
abatement along emergency and
evacuation routes
R16: Canopy assessment and canopy goals
R17: Tree preservation best practices
C1: General awareness of the urban forest as a
community resource
C2: Neighborhood cooperation
C3: Citizen, municipal, business, commuter
interaction
C4: Support by private land holders
I1: City public agency cooperation
I2: Design and development industry and other
government agency cooperation
I3: landscape and arboriculture industry
cooperation
I4: Cooperation within the geographic region
Iowa City Urban Forest Management Plan | 43
URBAN FORESTRY PROGRAM PROJECT FUNDING
Goal Four: Seek alternative mechanisms for funding and projects to accomplish the strategies (Table 18)
G4-1
Year 1: Continue to apply for the MidAmerican Energy
Plant Trees, Save Energy “Trees Please” grant and seek
additional funding opportunities.
Criteria:
• V – 1, 4
Responsible Agency: Forestry and Parks
G4-2
Year 5: Contract the 5-year urban forest inventory and
analysis with state universities or private consultants.
Criteria:
• R – 6
Responsible Agency: Forestry and Parks
As stated in the Adaptive Management section, the City must approach goal implementation with a flexible
decision-making process that can be adjusted in the face of uncertainties as outcomes from management actions
and other events become better understood. Careful monitoring of these outcomes both advances scientific
understanding and helps adjust policies or operations as part of an iterative learning process. Using an adaptive
management approach will require the consistent monitoring of all the City’s criteria for urban forest
sustainability. The City will be able to judge if its new approaches to urban forest conservation are being
effective, develop relationships between management actions and outcomes, and identify significant trends.
This will allow the City to adjust management actions over time as changes occur both in the physical/biological
environment and in the expectations of the City’s residents.
Figure described in the Adaptive Management section
20-Year Strategic Plan
5-Year
Management
Plan #1
5-Year
Management
Plan #2
5-Year
Management
Plan #3
5-Year
Management
Plan #4
Criteria Key
V1: Tree species diversity
V4: Planting and stocking levels
R6: Urban forest inventory public-private
Annual Operating Plans
Strategies Increasing detail The Process:
Criteria and performance indicators
identify 5-year management strategies
which inform annual operating plans.
The 5-year management plans allow for
an adaptive approach as the City strives
to achieve optimal levels of urban forest
management and sustainability.
Criteria and Performance Indicators
Iowa City Urban Forest Management Plan | 44
Summary & Conclusion
Iowa City’s 2018 Urban Forest Management Plan: Guiding the City along the Urban Forest Sustainability &
Management Spectrum
URBAN FOREST MANAGEMENT PLAN SUMMARY
Based on the analysis of the urban forest resource and existing program, criteria and performance indicators,
goals and strategies, and the measures and milestones for enhancing Iowa City’s urban forest were developed
and summarized.
Program & Data Analysis: Collection and review of documents, best practices,
initiatives, partners, surveys, and data pertaining to and impacting the urban forest. A review of
the 2016-2018 public street and park tree inventory was conducted.
The street and park tree inventory data were analyzed to determine the structure, maintenance
needs, potential risks, ecosystem benefits, and available planting space characteristics to inform
the Plan. These results were incorporated with the Urban Forest Sustainability & Management
Audit that consists of a review and ranking of 11 elements of urban forestry. This resource and
program audit informed development of the criteria and performance indicators.
Criteria & Performance Indicators: Indicators of urban and community forest
sustainability and management allow the City to identify the current status on the spectrum and
the requirements or criteria necessary to advance on a low to optimal spectrum. Criteria and
performance indicators were developed based on four categories: Vegetation Resource (the
trees), Resource Management (the staff), Community Framework (the people), and Institutional
Framework (the inter-agencies).
Measures, Goals, & Strategies: The program and data analyses established criteria
and performance indicators and the goals and strategies were developed to advance the City on
the Urban Forest Sustainability and Management Spectrum. The measures and milestones were
established so the City can evaluate progress and adjust strategies accordingly.
Image source: Classic Blank & McCune
Iowa City Urban Forest Management Plan | 45
The following provides a summary of the urban forest management planning process and outcomes.
Figure 21. The benefits and values of City-managed trees
Table 19. Summary of the 2018 Iowa City Urban Forest Management Plan
CITY & PARK TREE INVENTORY SUMMARY
2016-2018 Inventory
(based on April 2018 data)
25,451 street trees
19,563 park trees
4,972 planting sites
The following summaries are for street and park trees unless otherwise noted
Tree Diversity 66 genera, 178 species
Top 5 Species Silver Maple (8%), Northern Hackberry (6%), Green Ash (6%), Crabapple (6%),
and Mulberry (5%)
Size Distribution >30” (7%) 12-18” (17%)
24-30” (7%) 6-12” (32%)
18-24” (10%) 0-6” (27%)
Average Diameter (@4.5’) 12”
Tree Condition Excellent (2%) Poor (5%)
Good (47%) Critical/Dead (3%)
Fair (41%)
Maintenance Needs Removal (5%) Training Pruning (3%)
Priority Pruning (1%) None Needed (18%)
Routine Pruning (72%)
Removals by Size Class >30” (5%) 12-18” (19%)
24-30” (5%) 6-12” (36%)
18-24” (12%) 0-6” (23%)
EMERALD ASH BORER VULNERABILITY
Ash Tree Count 3,515
Counts by Condition Excellent (16) Poor (271)
Good (1,492) Critical/Dead (44)
Fair (1,685)
Counts by Size Class >30” (285) 12-18” (758)
24-30” (416) 6-12” (984)
18-24” (584) 0-6” (485)
Distribution of Ash Street (2,300) Parks (1,215)
Iowa City Urban Forest Management Plan | 46
URBAN FOREST PROGRAM SUMMARY
Criteria &
Performance
Indicators (the “Urban
Forest Management
& Sustainability
Spectrum”) Summary
Category Low Moderate Good Optimal Total
Vegetation Resource 0 3 1 1 5
Resource Management 2 5 7 3 17
Community Framework 1 2 1 0 4
Institutional Framework 0 4 0 0 4
Total 3 14 9 4 30
URBAN FOREST MANAGEMENT PLAN 5-YEAR GOALS
Category: Education
Goal One: Promote proper tree care through education and enforcement
Category: Organization & Management
Goal Two: Improve efficiencies and collaborate to propel urban forest management
Category: Plan Implementation
Goal Three: Build the team and the reinforcements to implement the Plan
Category: Urban Forestry Program Project Funding
Goal Four: Seek alternative mechanisms for funding and projects to accomplish the strategies
URBAN FOREST MANAGEMENT PLAN CONCLUSION & NEXT STEPS
Iowa City’s urban and community forest is a defining and valued characteristic of the City making it a desirable
place to live, work, and play. It is a resource that has a history and legacy of care and management but there are
existing and potential threats to this resource and areas for improvement in the care and enhancement of it.
This understanding incited the action to develop the Urban Forest Management Plan.
The assessment, criteria and indicators, goals and strategies, and measures for adaptive management that are
presented in this Urban Forest Management Plan have been created to provide a framework to effectively,
proactively, and sustainably manage the urban forest. This Plan should be disseminated and presented to City
agencies to gain awareness, support, and assistance in its implementation. Upon acceptance of this Plan,
outreach and education to the residents of Iowa City should be conducted.
As implementation progresses, the City should continually evaluate their progression along the Urban Forest
Sustainability and Management Spectrum using the measures and milestones provided. It is inevitable that
changes will occur to the vegetation resource, the resource management, community perspectives , and
institutional framework and thus, modifications of the strategies should be considered. This Plan provides the
20-year framework to advance along the Urban Forest Sustainability and Management Spectrum. The first 5-
year management plan goals and strategies initiate this journey. Each 5-year plan should be evaluated near the
end of each term in order to develop the next 5-year goals, strategies, measures, and milestones.
While it will take additional resources and efforts to achieve the goals of the Urban Forest Management Plan, its
implementation will help ensure that Iowa City’s urban and community forest will continue to thrive, be valued,
and provide enhanced benefits to the community and future generations.
“Our vision for the future of Iowa City is to create a healthy and sustainable urban
forest that is properly managed and cared for, benefiting our citizens with improved
economic and environmental well-being, increasing public safety, and enabling our
employees to provide cost-effective maintenance. Our urban forest will have a large
variety of trees consisting of various sizes, ages, and species. The trees will be selected
and maintained according to the Best Management Practices (BMPs) established by
the International Society of Arboriculture (ISA).”
Iowa City Urban Forest Management Plan | 47
“Trees and forests make Iowa
communities stronger. If properly cared
for, trees provide a wide variety of
benefits to people, communities and
the economy. An investment in our trees
is an investment in our future.”
│ Iowa DNR
Iowa City Urban Forest Management Plan | i
Appendices:
APPENDIX A. URBAN FOREST SUSTAINABILITY & MANAGEMENT AUDIT
APPENDIX B: STREET & PARK TREE INVENTORY METHODOLOGY
APPENDIX C: COUNT OF TREES BY CITY PARKS & TRAILS
APPENDIX D: BEST PRACTICES FOR TREE PRESERVATION
APPENDIX E: TREE MAINTENANCE BEST PRACTICES
APPENDIX F: URBAN FORESTRY RESOURCES
APPENDIX G: TREE & PLANTING SITE MAPS
APPENDIX H: EAB MANAGEMENT GUIDELINES & COMMUNITY OUTREACH
Iowa City Urban Forest Management Plan | ii
Appendix A. Urban Forest Sustainability & Management
Audit
The U.S. Urban Forest Sustainability & Management Audit was used for evaluating all categories and elements
pertaining to Iowa City’s urban forest to inform criteria and performance indicators, measures and milestones,
goals, and strategies.
THE DOCUMENT & RESOURCE DISCOVERY STAGE
1) Identify documents and resources pertaining to each of the categories
2) Review and list the documents and resources for each category element
Iowa City Urban Forest Management Plan | iii
3) Rate the level at which the City is achieving the element
4) The level at which the City is attaining optimal levels for each category element is calculated
5) Determines the level at which the City is achieving urban forest sustainability and management to
inform criteria and performance indicators, measures and milestones, goals, and strategies
Iowa City Urban Forest Management Plan | iv
Appendix B. Street & Park Tree Inventory Methodology
The 2016-2018 street and park tree inventory, facilitated by the Parks and Forestry Division, was conducted in
order to establish a baseline assessment of the City’s tree structure and maintenance needs. The tree inventory
crew used Plan-It Geo’s Tree Plotter inventory software to collect the following information:
- Location
- Common Name, Latin Name, and Genus
- Diameter at Breast Height (DBH, measured at 4.5’)
- Condition
- Observations
- Maintenance Needs
- Park Name (if applicable)
- Land Use
- Infrastructure Conflicts
- Presence of Wires
- Risk Assessment
- Date Added
- User
In addition to mapping of existing tree points, over 5,000 possible planting sites were mapped based on the
criteria established by the City. To help future planting efforts, possible planting sites were mapped and
categorized based on the available space.
Though Tree Plotter has built-in functionality to reduce error, after the inventory was completed, the arborists
and project managers completed a quality check (QA/QC) process to correct any misplaced tree points,
erroneous data, and other inconsistencies. City staff were provided with account information to access, view,
manage, update, filter, report, and export tree/planting site data. The data management, filters, and
stats/charts/graphs functionality in Tree Plotter were used to complete the inventory data analysis and
summaries to inform this Urban Forest Management Plan. The tree inventory software and collected
tree/planting site points can be viewed at www.pg-cloud.com/IowaCity.
Tree Plotter Software → Field Inventory → Data and Program Analyses → Urban Forest Management Plan
Iowa City Urban Forest Management Plan | v
TREE MAINTENANCE NEEDS CRITERIA & METHODOLOGY
The following maintenance categories were collected:
A. Immediate Removal - Trees designated as immediate removals are dead or have one or more defects
that cannot be cost-effectively remedied. EAB infested and stage were noted if present.
B. Removal - Trees designated as removals should be removed, but do not pose a liability as great as the
immediate priority or pose minimal liability. EAB infested and stage were noted if present.
C. Immediate Priority Pruning - Trees in this category require pruning to remove deadwood and/or broken
branches that pose a potential risk to people or property. These trees have broken and/or hanging limbs,
hazardous deadwood and dead, dying or diseased limbs or leaders greater than four inches in diameter.
EAB infested and stage were noted if present.
D. High Priority Pruning - Trees in this category require pruning to remove deadwood and/or broken
branches that pose a potential risk to people or property. These trees have broken and/or hanging limbs,
hazardous deadwood and dead, dying or diseased limbs or leaders greater than two but less than four
inches in diameter. EAB infested and stage were noted if present.
E. Routine Pruning - Trees in this category have characteristics that could become risks if not corrected.
Deadwood is less than two inches in diameter. EAB infested and stage were noted if present.
F. Training Pruning - This category includes trees less than 20 feet in height with correctable structural
problems or minor amounts of deadwood that pose little or no threat of personal injury or property
damage. Pruning at this stage is relatively inexpensive but can have significant effects in the future. EAB
infested and stage were noted if present.
PLANTING SITE CRITERIA & METHODOLOGY
Planting location - Locations where no tree exists,but fit with current city standards for a tree location.
Parameters include: Minimum of 10-30 linear feet (depending on species) to the trunk of the nearest tree,
minimum of 30 feet from fire hydrants, water lines, driveways and alley entrances, minimum of 10-30 linear feet
(depending on species) from street light poles, 30 feet from street intersections, parkway must be at least 6 feet
wide.
RISK ASSESSMENT CRITERIA & METHODOLOGY
A Level 2 Qualitative risk assessment was completed during the 2016-2018 inventory for street and park trees
based on ANSI A300 (Part 9) standards and the protocols in the Best Management Practices: Tree Risk
Assessment, published by the International Society of Arboriculture (2011). Trees are subject to various failure
scenarios which help determine risk rating. The failure mode (i.e., branch, whole tree, codominant stem) with
the greatest risk served as the overall tree risk rating. The specified time period for the risk assessment
completed during the 2016-2018 inventory is one year.
Ratings were determined by the following criteria:
A. Likelihood of Failure. Identifies the most probable failure and rates the likelihood that structural
defect(s) will result in failure based on observed current conditions.
B. Likelihood of Impacting a Target. The rate of occupancy of targets within the target zone and any factors
that could affect the failed tree as it falls toward the target.
C. Categorizing Likelihood of Tree Failure Impacting a Target. The likelihood of failure and target impact
are combined in the matrix below to determine the likelihood of tree failure impacting a target.
Iowa City Urban Forest Management Plan | vi
Likelihood of
Failure
Likelihood of Impacting Target High Very Low Low Medium
Imminent Unlikely Somewhat Likely Likely Very Likely
Probable Unlikely Unlikely Somewhat Likely Likely
Possible Unlikely Unlikely Unlikely Somewhat Likely
Improbably Unlikely Unlikely Unlikely Unlikely
Consequence of Failure
The consequences of tree failure are based on the level of target and potential harm that may occur.
Consequences can vary depending upon the size of defect, distance of fall for the tree or limb, and any other
factors that may protect a target from harm. Target values are subjective, but efforts were made to assess them
from the City’s perspective as discussed during the inventory project kickoff.
Risk Rating
The tree’s risk rating was determined based on combining the likelihood of tree failure impacting a target and
the consequence of failure in the matrix below.
Likelihood of
Failure
Consequences
Neglible Minor Significant Severe
Very Likely Low Moderate High Extreme
Likely Low Moderate High High
Somewhat Likely Low Low Moderate Moderate
Unlikely Low Low Low Low
Iowa City Urban Forest Management Plan | vii
Appendix C. Count of Trees by City Parks & Trails
(Names as listed in the Tree Plotter app)
Park Name Tree Count % Within
test park 2 1 0.0%
Tyrrell mill park 1 0.0%
Trail 4 0.0%
Harlocke Hill park 6 0.0%
Highland park 7 0.0%
Tower court park 9 0.0%
Bristol drive 10 0.1%
Happy hollow park 14 0.1%
Reno street park 15 0.1%
Weatherby park 18 0.1%
Iowa city water 19 0.1%
Black springs circle park 22 0.1%
Frauenholtz-Miller Park 23 0.1%
Creekside park 29 0.1%
Iowa city soccer complex 29 0.1%
Ryersons woods 29 0.1%
Crandic park 30 0.2%
Lower city park 31 0.2%
Brookland park 36 0.2%
Chadek green park 36 0.2%
Sturgis ferry park 37 0.2%
Fairmeadows 40 0.2%
Oak grove park 42 0.2%
Longfellow nature trail 45 0.2%
Thornberry dog park 45 0.2%
Glendale park 47 0.2%
Weber elementry 56 0.3%
Cardigan park 58 0.3%
North Market Park 59 0.3%
City of iowa city 61 0.3%
Pheasant Hill park 62 0.3%
Court Street trail 67 0.3%
College Green 68 0.3%
Villa park 70 0.4%
Wetherby 80 0.4%
Whispering meadows wetland park 82 0.4%
Thornbury trail 105 0.5%
Terrell mill park 106 0.5%
Court Hill Park 166 0.8%
Benton hill park 167 0.9%
Windsor ridge park 175 0.9%
Scott park 194 1.0%
Iowa City Urban Forest Management Plan | viii
Scott park trail 202 1.0%
Mercer park 223 1.1%
Waterworks Prairie park 283 1.4%
Upper City Park 291 1.5%
Hunters run park 390 2.0%
Kwanis park 441 2.3%
Willow Creek trail 647 3.3%
Oakland cemetery 958 4.9%
Sycamore trail 1027 5.2%
Iowa river rc trail 1554 7.9%
Willow creek park 2355 12.0%
Hickory Hill park 2468 12.6%
Peninsula Park 2918 14.9%
Terry Trueblood Recreation Area 3605 18.4%
19563 100.0%
Iowa City Urban Forest Management Plan | ix
Appendix D. Best Practices for Tree Preservation
The following provides an example of how to develop tree preservation best practices and standards structure,
building, and utility construction or repair that is within the right-of-way and will directly or indirectly impact
trees in proximately to the site.
Damage to City-owned trees due to permit-holder negligence or accident shall be repaired only by the Forestry
section. Forestry shall remove and replace any trees, determined to be excessively damaged. The cost of all
such repairs, removals, replacements, and an amount of value lost will be the liability of the permit-holder and
billed accordingly.
The directional bore route is outside of the tree border and under or behind the sidewalk for this project.
To preserve the tree's root system and maintain structural stability, no open cut excavation or bore pits
allowed within 8 ft of City street trees. This includes Hand Holes. Boring entry and exit points should be located
in areas that avoid root damage.
Any tree roots encountered are to be cleanly cut using hand tools. Do not remove roots using excavation
equipment.
Cables, ducts, conduits, and other utilities installed in the right of way shall maintain a 5' minimum horizontal
clearance from all City street trees.
In order to avoid damage to tree roots, branches, and trunks of City street trees, no construction equipment or
materials shall be placed, parked, or stored on any unpaved area within the drip line of any City owned tree.
The City’s Urban Forestry Inspector shall frequently monitor construction sites containing City street trees and
any change in tree conditions will be recorded. Any questions or concerns regarding City trees contact Forestry
Inspector ____________at
The top four feet of all excavations in the right of way and in all boulevard medians shall be backfilled with
clean viable soil. No concrete, slurry, gravel, sand or other such material shall be used for backfill. Restoration
shall be to original grade unless otherwise specified.
New poles, anchors, vaults, hand holes, or other above-ground structures must be located outside the drip line
of City street trees.
The median islands may contain a buried irrigation system and components. Any irrigation damaged or
disturbed will be reported to the Forestry Inspector. Any repairs needed will be completed by the Forestry
department at the contractor’s expense. Boulevard medians shall not be used to store equipment or materials.
OCCUPANCY AND DEPOSIT COMMENTS FOR WHEN TREES ARE INSIDE THE PROJECT LIMITS: I normally take a
deposit on any trees in the right away that might get damaged during larger projects and if trees are damaged
or removed I will keep the fee.
If they know the tree needs to be removed due to construction or other reasons, we will add a Forestry Service
Fee to the permit giving them permission to remove the tree and charge them $100.00 per diameter inch.
Examples:
Iowa City Urban Forest Management Plan | x
All City street trees near any excavation, demolition, or construction of any building or structure must be
sufficiently guarded and protected by those responsible for such work as to minimize potential injury to the
trees and to maximize their chance for survival.
There are City Street trees with in the project limits. A deposit of ________ is required. Deposit represents
equity value of City street trees in work area. Deposit will be returned upon completion of project if trees are
not damaged or removed.
Removal of 2 City street trees has been proposed as part this permit. The permit holder will be responsible for
the cost of removing said street trees in the City’s right of way. The value of the trees will be added to the
permit as a Forestry Service fee. Value of tree is based on $100.00 per diameter inch of the trunk at 4 1/2 feet
above ground.
Private sprinkler notes:
There are City of ### street trees located in the public right-of-way. These trees are maintained by the
Forestry department. If, during the removal or installation of any City street trees by Forestry crews that
result in damage to an irrigation system located in the public right-of-way, the Owner of said system shall bear
all responsibility and costs associated with its repair.
Should a private irrigation system become obsolete, nonfunctional, poorly maintained, or
protruding from grade, the City may require repair or removal of all or a portion of such system
within 30 days of written notice from the City to do so. If the owner fails to so repair or remove,
then after two such written notices to the owner, the City may cause removal of the system at
the owner’s expense.
Sprinkler heads are to be installed a minimum of four (4) feet away from any city owned tree.
Lawn watering systems in the right of way are for personal convenience, and may be disrupted without notice
at any time by the City in performance of its work. Any costs associated with such disruption including water
loss, repair, and replacement shall be solely the responsibility of the owner of the watering system.
Iowa City Urban Forest Management Plan | xi
Appendix E. Tree Maintenance Best Practices
Urban forests play a significant role in maintaining the health and vitality of urban life. The urban forest provides
a wealth of benefits to neighborhoods and residents through the reduction of energy consumption, the removal
of pollutants from the air and water, reduction in stormwater flows, increased valuation of private property,
increased worker productivity, reduction in stress and violent crime, as well as providing recreational
opportunities and aesthetic diversity. At the same time stresses from the urban environment including air
pollution, damage by vehicles, increased impervious surface, soil compaction, and maintenance neglect reduce
the diversity and magnitude of these benefits and may lead to tree-related problems.
The inherently close interaction between people and trees in cities requires active and diligent management of
the urban and community tree and forest resources to ensure public safety. To enhance tree canopy and
associated benefits, trees need to be properly maintained and planted.
Tree Maintenance Best Practices
The following provides an overview of tree maintenance best practices. It is not intended to be an extensive or
comprehensive summary of best practices. All tree maintenance practices should follow the American National
Standards Institute’s (ANSI) A300 Standards (Parts 1-10).
Reasons for Tree Pruning
1. Pruning for Safety
Involves removing branches that could fall and cause injury or property damage, trimming branches that
interfere with lines of sight on streets or driveways, and removing branches that grow into utility lines.
Safety pruning can be largely avoided by carefully choosing species that will not grow beyond the space
available to them and have strength and form characteristics that are suited to the site.
2. Pruning for Health
Involves removing diseased or insect‐infested wood, thinning the crown to increase airflow and reduce
some pest problems, and removing crossing and rubbing branches. Pruning can best be used to
encourage trees to develop a strong structure and reduce the likelihood of damage during severe
weather. Removing broken or damaged limbs encourages wound closure.
3. Pruning for Form
Improves the structure of trees and removes branches that are more likely to fail. Branches that are
poorly attached may be broken off by wind and accumulation of snow and ice. Branches removed by
such natural forces often result in large, ragged wounds that rarely seal.
4. Pruning for Aesthetics
Involves enhancing the natural form and character of trees or stimulating flower production.
To reduce the need for pruning it is best to consider a tree’s natural form. It is very difficult to impose an
unnatural form on a tree without a commitment to constant.
Iowa City Urban Forest Management Plan | xii
Common Types of Tree Pruning
1. Crown Cleaning
Consists of the selective removal of dead, dying, diseased, and weak branches from a tree’s crown. No
more than 25% of the live crown should be removed in any one year, even for young trees.
2. Crown Thinning
Primarily for hardwoods, thinning is the selective removal of branches to increase light penetration and
air movement throughout the crown of a tree. The intent is to maintain or develop a tree’s structure
and form. To avoid unnecessary stress and prevent excessive production of epicormic sprouts, no more
than one‐quarter of the living crown should be removed at a time. If it is necessary to remove more, it
should be done over successive years.
Branches with strong U‐shaped angles of attachment should be retained. Branches with narrow, V‐
shaped angles of attachment often form included bark and should be removed.
3. Crown Raising
The practice of removing branches from the bottom of the crown of a tree to provide clearance for
pedestrians, vehicles, buildings, lines of site, or to develop a clear stem for timber production. After
pruning, the ratio of the living crown to total tree height should be at least two‐thirds. On young trees
temporary branches may be retained along the stem to encourage taper and protect trees from
vandalism and sunscald.
4. Crown Reduction
Most often used when a tree has grown too large for its permitted space. This method, sometimes called
drop crotch pruning, is preferred to topping because it results in a more natural appearance, increases
the time before pruning is needed again, and minimizes stress (see drop crotch cuts in the next
section). Crown reduction pruning, a method of last resort, often results in large pruning wounds.
Figure 22. Types of tree pruning
Image source: www.owentree.com
Iowa City Urban Forest Management Plan | xiii
Tree Pruning Cuts
Pruning cuts should be made so that only branch tissue is removed and stem tissue is not damaged. To find the
proper place to cut a branch, look for the branch collar that grows from the stem tissue at the underside of the
base of the branch. On the upper surface, there is usually a branch bark ridge that runs parallel to the branch
angle, along the stem of the tree. A proper pruning cut does not damage either the branch bark ridge or the
branch collar. A proper cut begins just outside the branch bark ridge and angles down away from the stem of
the tree, avoiding injury to the branch collar.
Figure 23. Types of pruning cuts and the proper branch cutting technique
Utility Tree Maintenance Best Practices
Utility Tree Pruning Overview
The city should work with the utility companies to ensure proper pruning practices are followed and that open
communication between the company, the city, and the public are maintained. The International Society of
Arboriculture provides guidelines for maintaining trees near power lines (Best Management Practices – Utility
Pruning of Trees, G. Kempter).
Maintaining power lines free of tree growth is based on a consistent, planned trimming cycle of the utility
vegetation management company. This approach improves electric service to all the customers who get their
power from that line. A sensible approach to trimming trees means having a thorough maintenance plan that
improves the safety and reliability of electric service to residents. Residents and the city staff should not attempt
to trim any vegetation growing near or on any overhead power lines.
Utility Tree Maintenance Techniques
1. Directional Pruning
Removes entire branches and limbs to the main trunk of the tree and future growth is directed away
from the power lines. Reduction cuts are used for removing these branches and limbs and should be
pruned properly back to a lateral branch that is at least one-third the diameter of the branch being
removed. This allows for good wound closure and protects apical dominance and reduces sprouts.
Avoid topping or rounding over trees. This removes more foliage than directional pruning, increases the
number of tree wounds, stresses the tree, causes unstable decay, and increases water sprouts.
2. Right Tree Right Place
Photo source: Pennsylvania State University Urban Forestry Extension
Iowa City Urban Forest Management Plan | xiv
Selecting the right tree for the site can reduce potential safety hazards and improve the reliability of the
electric service. Smaller trees near power lines do not need to be excessively pruned and do not lose
their natural form.
3. Recommended Trees
Trees potentially suitable for planting adjacent to power lines includes fringetree (Chionanthus
virginicus), wax myrtle (Morella cerifera), crape myrtle (Lagerstromea indica), and Japanese privet
(Ligustrum japonicum). Additional species should be considered and listed in a recommended species
list.
Figure 24. Example of trees directionally pruned for clearance from power lines
Young Tree Maintenance Best Practices
Proper pruning is essential in developing a tree with a strong structure and desirable form. Trees that receive
the appropriate pruning measures while they are young will require less corrective pruning as they mature.
Young Tree Maintenance Techniques
1. Consider the Nature Form and Desired Growth
Accentuate the natural branching habit of a tree and correct any structural problems over time, if
needed, to not stress the tree.
2. Pruning in 1-2 Years after Planting
Prune as little as possible after planting to ensure there are enough temporary branches to produce
food for new growth of roots, trunk, and branches. Prune only dead, broken, malformed, or diseased
branches. Remove codominant leaders to maintain one dominant trunk. Prune for clearance if
absolutely necessary. Keep size of branch removed to less than one inch in diameter.
3. Pruning 2-3 Years after Planting
Prune any dead, broken, malformed, or diseased branches. Remove any suckers from the base of the
tree. Next, determine the permanent branch structure by considering:
• Remove, thin, or cut back any competing leaders
• Remove crossing or rubbing branches, keeping the branch that maintains the natural form
• Thin excessively crowded branches but do not lions-tail
• Remove branches with narrow angles between the branch and trunk (consider species)
• Remove branches to maintain well-spaced branches along and around the trunk. Ideal mature
trees will have lateral branches that are 18-24 inches apart (depending on species)
Photo source: Pennsylvania State University Urban Forestry Extension
Iowa City Urban Forest Management Plan | xv
• Avoid pruning near time of bud break
• Prune flowering trees after flowering
Figure 25. Example of branches to be pruned for newly planted trees to promote good structure
Tree Planting Best Practices
The following provides an overview of best practices that should be considered and followed before during and
after planting trees.
• Trees to be planted should be selected from an approved tree planting list developed to maintain and
enhance species diversity that are suitable for Plant Hardiness Zone 9b and changing climates.
• Planting material will conform to the latest version of the American Standard for Nursery Stock
(American National Standards Institute [ANSI] Z60.1). Trees to be planted should be of standard quality
or better, and should be true to name and type of their species variety.
• Trees should not be planted in tree lawns less than 2 feet in width or in planting pits less than 5 feet
long by 5 feet wide.
• Trees should not be planted within 50 feet of any major intersection, or within 20 feet of a fire
hydrant, a driveway, or a pole supporting a light.
• The burlap and twine from balled-and-burlap trees should be removed from the tree and the tree pit.
Wire tree baskets may remain on the root ball, but the top one-third should be clipped and removed
from the planting hole.
• Mulch should be placed around trees in a minimum 3-foot circle and 3-inch depth to protect trees
from lawnmower damage and competition from turf; mulch will be kept away from tree trunks.
• Newly planted trees should be irrigated weekly during droughts in the growing season for three years.
1. Prune competing leader
2. Prune malformed branches
3. Remove crossing branches
4. Remove water sprouts
5. Remove branches with poor angles
6. Prune broken or damaged branches
7. Prune temporary branches over time
8. Remove suckers
9. Apply 2-3” of mulch
Photo source: Pennsylvania State University Urban Forestry Extension
Iowa City Urban Forest Management Plan | xvi
Appendix F. Urban Forestry Resources
Local Resources
• EAB - https://www.icgov.org/emeraldashborer
• Tree Plotter app - https://pg-cloud.com/IowaCity/
• Planting in the ROW brochure - https://www8.iowa-city.org/weblink/0/doc/1540628/Electronic.aspx
• Tree Planting Permit - https://www8.iowa-city.org/weblink/0/doc/1480598/Electronic.aspx
• Scout Projects brochure - https://www8.iowa-
city.org/weblink/0/edoc/1564002/Scout%20Project%20Brochure.pdf
• DNR Urban Forestry - http://www.iowadnr.gov/Conservation/Forestry/Urban-
Forestry/UrbanForestryCouncil
• ISU Forestry Extension - https://www.extension.iastate.edu/forestry/
• Common trees of IA -https://www.extension.iastate.edu/forestry/iowa_trees/trees/index.html
• Iowa City tree removal procedure - https://www.icgov.org/city-government/departments-and-
divisions/parks-and-recreation/parks-and-forestry/tree-removal
• Iowa City Trail Map - https://www8.iowa-city.org/weblink/0/doc/1512414/Electronic.aspx
• Design Guidebook - Maximizing Climate Adaptation Benefits with Trees
Community Outreach and Education
• The Nature Conservancy “Health Trees, Healthy Cities”:
https://www.conservationgateway.org/ConservationPractices/cities/hthc/Pages/default.aspx/training-
resources
• US Forest Service “Outreach Services Strategies for all Communities”:
http://actrees.org/files/What_We_Do/OutreachStrategies.pdf
• Project Learning Tree: https://forestry.ces.ncsu.edu/ncplt/
Emerald Ash Borer & Other Pests
• Iowa DNR EAB Page: http://www.iowadnr.gov/Conservation/Forestry/Forest-Health/Emerald-Ash-Borer
• IA Department of Ag “Iowa Tree Pests: http://www.iowatreepests.com/eab_home.html
Regional Urban Forestry
• National Urban and Community Forestry Advisory Council: https://www.fs.fed.us/managing-land/urban-
forests/ucf/nucfac
• American Forests: http://www.americanforests.org/
• Urban Forestry Index: www.urbanforestryindex.com
• TreeLink: www.treelink.org
• Trees Are Good: www.treesaregood.org
• American Grove: http://thegrove.americangrove.org/
• Society of Municipal Arborists: http://www.urban-forestry.com/
• Arbor Day Foundation: www.arborday.org
• Alliance for Community Trees: https://www.arborday.org/programs/alliance-for-community-trees/
• Tree Care Industry Association: http://www.tcia.org/
Tree Ordinances
• Guidelines for Developing and Evaluating Tree Ordinances (automatic download):
• https://ir.library.oregonstate.edu/downloads/pg15bm22x
• Sample Tree Ordinance:
• https://www.arborday.org/programs/treecityusa/documents/sample-tree-ordinance.pdf
• Example Tree Contracting Specifications: https://www.springfieldmo.gov/DocumentCenter/View/11756
• Trees and Development Guidelines: http://www.a2gov.org/departments/field-
operations/forestry/Pages/StreetTreesDevelopment.aspx
Iowa City Urban Forest Management Plan | xvii
• American Public Works Association “Urban Forestry Best Management Practices for Public Works
Managers: Ordinances, Regulations, & Public Policies”:
https://www2.apwa.net/Documents/About/CoopAgreements/UrbanForestry/UrbanForestry-3.pdf
Urban Forest Storm Preparedness
• IA DNR Disaster Preparedness: http://www.iowadnr.gov/About-DNR/Social-Media-Press-Room/Disaster-
Assistance
• Urban Forest Strike Teams: http://articles.extension.org/pages/71461/urban-forest-strike-teams
• APA “Hazardous Tree Management and Post-Disaster Tree Management”:
https://www.planning.org/research/treemanagement/
Trees and Stormwater
• Urban Watershed Forestry Management: http://www.forestsforwatersheds.org/
• EPA Green Infrastructure: http://water.epa.gov/polwaste/green/upload/stormwater2streettrees.pdf
• OKI Regional Council of Governments “Trees & Stormwater”: http://treesandstormwater.org/
Urban Forests and Climate Change
• US Forest Service “Urban Forests and Climate Change”: https://www.fs.usda.gov/ccrc/topics/urban-
forests-and-climate-change
Tree Management Best Practices
• ANSI A300 Standards:
https://tcia.org/TCIA/BUSINESS/ANSI_A300_Standards_/TCIA/BUSINESS/A300_Standards/A300_Standar
ds.aspx?hkey=202ff566-4364-4686-b7c1-2a365af59669
• ANSI A300 Pruning Specification Writing Guide:
https://www.tcia.org/TCIAPdfs/Resources/Arboriculture/A300TreeCareStandards/A300Pruning-
SpecificationWritingGuide-20170413.pdf
Trees and Utilities
• Penn State Extension “Questions about Trees and Utilities”: https://extension.psu.edu/questions-about-
trees-and-utilities
• Utility Arborist Association “Common Questions about Electric Utility Pruning”:
https://uaa.wildapricot.org/page-18073
• VA Cooperative Extension “Trees and Shrubs for Problem Landscape Sites: Overhead Utility Easements”
(automatic download): https://www.urbanforestrysouth.org/resources/library/ttresources/trees-and-
shrubs-for-problem-landscape-sites-overhead-utility-easements/at_download/file
• The eXtension Foundation “Trees for Energy Conservation”:
http://articles.extension.org/trees_for_energy_conservation
• Arbor Day Foundation “Energy-Saving Trees”: http://energysavingtrees.arborday.org/#About
Urban Wood Utilization
• http://ncufc.org/urban_wood_utilization_introduction.php
Planning Resources
• US Forest Service and Davey Institute “Sustainable Urban Forest Guide”:
http://www.itreetools.org/resources/content/Sustainable_Urban_Forest_Guide_14Nov2016.pdf
• WI DNR “Technical Guide to Developing Urban Forestry Strategic Plans & Management Plans:
http://dnr.wi.gov/topic/UrbanForests/documents/UFPlanningGuide.pdf
• Municipal Urban Forestry Staff American Public Works Association “Urban Forestry Best Management
Practices for Public Works Managers: Staffing”:
https://www2.apwa.net/Documents/About/CoopAgreements/UrbanForestry/UrbanForestry-2.pdf
• Tree Boards: http://www.tufc.com/pdfs/treeboard_handbook.pdf
Urban Forestry Funding
• Davey Resource Group “Funding Your Urban Forest Program”: http://www.urban-
forestry.com/assets/documents/funding-your-uf-program-jenny-gulick.pdf
Iowa City Urban Forest Management Plan | xviii
• Alliance for Community Trees “Funding Sources”: http://actrees.org/resources/tools-for-
nonprofits/fundraising-tools-for-nonprofits/
• Penn State Extension “Sustaining and Funding an Urban Forestry Program”:
https://extension.psu.edu/sustaining-and-funding-an-urban-forestry-program
• American Public Works Association “Urban Forestry Best Management Practices for Public Works
Managers: Budgeting & Funding”:
https://www2.apwa.net/Documents/About/CoopAgreements/UrbanForestry/UrbanForestry-1.pdf
Tree and Urban Forest Ecosystem Benefits
• US Forest Service i-Tree: www.itreetools.org
• US Forest Service Midwest Community Tree Guide:
https://www.fs.fed.us/psw/publications/documents/psw_gtr199/psw_gtr199.pdf
• US Forest Service “The Urban Forest and Ecosystem Services”:
https://www.fs.fed.us/psw/publications/mcpherson/psw_2016_mcpherson001_livesley.pdf
Tree Assessment Resources
• US Forest Service Urban Tree Canopy Assessments (UTC): www.nrs.fs.fed.us/urban/utc/
• Plan-It Geo Urban Tree Canopy Assessments: http://www.planitgeo.com/urban-tree-canopy
• i-Tree Canopy Assessments: https://canopy.itreetools.org/
• Plan-It Geo Tree Inventory Software: www.treeplotter.com
Other Resources
• American Forests “Vibrant Cities Lab”: http://www.vibrantcitieslab.com/
• Urban Forestry South “Resources and Links”: https://www.urbanforestrysouth.org/resources/links
• ISA International Dictionary Online: https://wwv.isa-arbor.com/education/onlineresources/dictionary
• Plan-It Geo Reports and Plans: https://issuu.com/planitgeoissuu
Iowa City Urban Forest Management Plan | xix
Appendix G. Tree & Planting Site Maps
HIGH AND EXTREME RISK TREES
https://pg-cloud.com/IowaCity/?scenario=HighRiskTrees (requires an account)
Iowa City Urban Forest Management Plan | xx
TREES RECOMMENDED FOR REMOVAL
https://pg-cloud.com/IowaCity/?scenario=TreesForRemoval (requires an account)
Iowa City Urban Forest Management Plan | xxi
TREES RECOMMENDED FOR IMMEDIATE PRIORITY PRUNING
https://pg-cloud.com/IowaCity/?scenario=ImmediatePruning1 (requires an account)
Iowa City Urban Forest Management Plan | xxii
TREES RECOMMENDED FOR HIGH PRIORITY PRUNING
https://pg-cloud.com/IowaCity/?scenario=HighPriorityPruning1 (requires an account)
Iowa City Urban Forest Management Plan | xxiii
LOCATION AND DBH OF ASH TREES
https://pg-cloud.com/IowaCity/?scenario=AshTrees (requires an account)
Iowa City Urban Forest Management Plan | xxiv
LOCATION AND SIZE OF PLANTING SITES
https://pg-cloud.com/IowaCity/?scenario=PlantingSites-Size (requires an account)
Iowa City Urban Forest Management Plan | xxv
Appendix H. EAB Management Guidelines & Community
Outreach
SUMMARIES OF ASH TREES ALONG STREETS
EAB GUIDELINES & OUTREACH APPROACH
The City’s approach to emerald ash borer (EAB) management and a summary of ash tree distribution is described
in the Vulnerability to Emerald Ash Borer of City-Managed Trees section on page 22.
This appendix provides more detail on the guidelines for EAB management and community outreach. As
feasible, the City will seek to save trees that are mature but not past ~75% of their expected life expectancy as
determined by qualified City staff. Among the treatable trees, the City will prioritize trees that contribute the
most to streetscapes, for example, at intersections and highly visible areas. The City will seek to avoid extensive
eradication of ash trees along any one city block at a given time to minimize the visual, economic, and ecosystem
impacts. The City will use these infestations as opportunities to increase tree diversity during replanting.
The citizens of Iowa City can be informed about EAB and the management procedures, plans, options, and status
on the City’s website (www.icgov.org/emeraldashborer) and through outreach materials that are in
development. Citizens will be given the opportunity to treat or cost-share on the treatment of public trees that
they want to save. These guidelines and approaches may be applied to future tree pest and disease issues.
The City provided a presentation on the Emerald Ash Borer Response Plan in March of 2016. In the presentation,
information regarding homeowner treatment options was provided. The table below summarizes the options
available for homeowners to treat ash trees on their private property.
Type of Application Active Ingredient
Tree Size
Trunk circumference
(diam. @ 4.5ft -dhb)
Time of Application
Soil drench Imidacloprid
(1.47%)
Up to 60”
(20” dbh)
Mid-April to mid-May or
Early Aug to mid-Sept
Soil drench Imidacloprid
(21.4%)
Up to 60”
(20” dbh) Early Aug to mid-Sept
Soil drench Imidacloprid,
Clothianidin
Up to 60”
(20” dbh)
Mid-April to mid-May or
Early Aug to mid-Sept
Granular Dinotefuran
(2%)
Up to 36”
(12” dbh) Mid-April to mid-May
Granular Imidacloprid,
Clothianidin
Up to 36”
(12” dbh) Mid-April to mid-May
Granular Imidacloprid Up to 36” Mid-April to mid-May
50%
40%
8%
1%1%
0%
10%
20%
30%
40%
50%
60%
Summary of the condition of street ash trees
1%
6%
24%24%
21%
14%
10%
0%
5%
10%
15%
20%
25%
30%
0-3in 3-6in 6-12in 12-18in 18-24in 24-30in >30in
Summary of the size distribution of street ash trees
Iowa City Urban Forest Management Plan | xxvi
(12” dbh)