04/21/23 1
A Tale of Four CitiesA Tale of Four CitiesExotic and Invasive Pest Analysis
and Issue CharacterizationPresented by:
Davey Resource GroupDeborah Sheeler
Project Partners
This project was made possible by:
U.S. Department of Agriculture Forest Service
Illinois Department of Natural Resources
City of Evanston
Village of Skokie
Village of Wilmette
Village of Winnetka
What’s Happening?
Our urban forests are threatened by exotic and invasive insects and diseases.
How can we best manage?
Where to Start?
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?Public Tree Inventories
Management Plans
Urban Tree Canopy Analysis
Tree OrdinancesHyperspectral Imagery
i-Tree Streets Benefits Model
Funding
In 2009, Illinois Department of Natural Resources was awarded a grant from the Northeastern Area State and Private Forestry Council to analyze:
Effectiveness and practicality of using various management tools and strategies to control exotic pest threats to public and private forests.
Project Goals
Assist communities to better understand what management tools are available for assessing the threat of exotic and invasive pests to their community forests
Demonstrate the advantages and limitations of select management tools, and the deliverables and costs associated with these tools
A Tale of Four CitiesA Tale of Four Cities
The urban forests in the Chicago, Illinois area are under intense pressure from exotic invasive insects and diseases. The four communities of Evanston, Skokie, Wilmette, and Winnetka have all implemented various management strategies to battle these exotic pests.
This is their tale…..
Background of Four CitiesBackground of Four Cities
The four communities of Evanston, Skokie, Wilmette, and Winnetka are all designated as a Tree City USA by the National Arbor Day Foundation
The project area is 27 square miles with city populations ranging from 12,000 to 74,000
All communities had existing tree ordinances and management plans
With the exception of Winnetka, all had a current inventory of public street trees
None of the four communities were utilizing hyperspectral imagery, i-Tree Streets Benefit Model, or Urban Tree Canopy Analysis
Exotic Invasive Insects and Diseases Evaluated
Emerald Ash Borer – EAB(Agrilus planipennis)
Dutch Elm Disease – DED (Ophiostoma novo-ulmi)
Oak Wilt (Ceratocystis fagacearum)
Tools and Management Strategies Analyzed
Tree Ordinances - SummaryIn A Tale of Four Cities, the ordinances of Evanston, Skokie, Wilmette, and Winnetka are examples of how this legal tool can be used effectively to manage invasive insects and diseases within municipal boundaries.
Advantages:Provide the legal framework within which local tree management activities are conducted for the general welfare and for specific issuesExpand the municipality’s ability to take legal and appropriate action on privately owned trees
Limitations:Must be formally adopted by the municipalityAre not effective if not enforced properlyCan be too species specific Need to be updated and reviewed periodically
Management Plans – SummaryThe communities of Evanston, Skokie, Wilmette, and Winnetka all rely on management plans or strategies to guide them in reducing the negative impacts of invasive insects and diseases.Advantages:
Establish goals and make management recommendations for tree care activitiesCreate unique approaches, like cost-share programs to incentivize
proactive management on the part of property ownersProvide action plans, budgets, and timelines for implementation of management strategiesProvide protocols and set standards for managing exotic invasive pests
Limitations:Can become outdated if not reviewed and updatedGoals of community may change and new threats may develop
Public Tree Inventories – SummaryEvanston, Skokie, and Wilmette have conducted complete tree inventories. The Village of Winnetka does not have a current tree inventory so a 6% random i-Tree Streets inventory was conducted. Inventories are valuable tools for managing threats to a community.Advantages:
The costs of performing and maintaining inventories have proven to be a worthwhile investment in relation to the benefits
Data collection that includes location, species, condition, size, and recommended maintenance information can be used to accurately report the effect of exotic invasive pests
Data can be used for short- and long-term budgeting and planningA GIS-based inventory will better demonstrate the spatial placement of the community’s
treesLimitations:
It is vitally important to maintain and update the tree inventory on a regular basis or the investment loses value in the long term
i-Tree Streets Benefit Model - Summary In A Tale of Four Cities, i-Tree Streets was a cost-benefit analysis tool used to quantify the environmental services that the entire street tree population provides as well as what the susceptible species of oak, elm, and ash street trees contribute. Advantages:
The highest benefit of i-Tree is using the results to communicate the benefits of trees and the need for increased proactive management
i-Tree results can be utilized to develop effective public relation and educational campaignsi-Tree is a defensible methodology that can show there is a positive benefit-cost ratio for
managing this municipal assetLimitations:
Tree inventory data must be available and it requires technical expertise to execute the analysis and fully use all of the capabilities of the program
i-Tree provides benefits for species that comprise over 1 percent of the total street tree population. Reports for all species that exist may not be available.
Hyperspectral Imagery - SummaryFor A Tale of Four Cities, HSI was used to depict the location and concentrations of green and white ash, American elm, and northern red oak tree canopy that are at risk to invasive insects and diseases.Advantages:
Hyperspectral Imagery as a separate tool is beneficial in visually depicting and mapping the canopy of targeted tree species
Community foresters can utilize HSI maps for effective communication for the need for proactively managing the potential threats from invasive insects and diseases to avoid loss of tree canopy to a community’s urban forest
HSI identifies both private and public trees and gives a complete picture of the community forestLimitations:
The cost may be prohibitiveA HSI project is only a “snapshot” of conditions at the time of the project
Hyperspectral Imagery - Results
Predicted Loss of Canopy Due to Invasive Insects and Diseases
Species Evanston Skokie Wilmette Winnetka
green and white ash 35.1 34.4 28.0 31.4
American elm 15.3 8.6 8.8 8.7
northern red oak 12.9 11.7 8.2 9.3
Total Canopy (acres) 63.3 54.7 45.0 49.4
Hyperspectral imagery (HSI) is a relatively new remote-sensing technology that can be used to map the canopy of both public and private trees at the species level.
Urban Tree Canopy Analysis - SummaryMunicipalities can use Urban Tree Canopy (UTC) data to better plan for potential planting projects and to further assist their public relation campaigns in response to invasive threats.Advantages:
The results of a UTC can be used to establish baseline conditions, benchmark against similar communities, set goals for improvement, and create plans for planting and protecting trees
UTC mapping is GIS-compatible and can be used by the community and stakeholders for many other uses
Limitations:A UTC is not species-specific and does not determine the percentage of canopy threatened
by invasive insects and diseases UTCs are best used in combination with other GIS data and imagery
Urban Tree Canopy Analysis - ResultsTotal Acres of Tree Canopy
Evanston Skokie Wilmette Winnetka
1,842.8 (36.9%)
1,850.1 (28.8%)
1,510.2 (43.6%)
1,306.5 (52.7%)
Urban Tree Canopy (UTC) analysis utilizes remote-sensing and GIS technologies to determine the cover of leaves, stems, and branches of trees.
Conclusions
Comparison of Management Tools
Tools
Co
st
Sp
atia
l (G
IS)
A
nal
ysis
Tre
e C
ano
py
Info
rmat
ion
En
viro
nm
enta
l B
enef
its
Tre
e S
pec
ies
D
ata
Man
agem
ent
Pu
blic
Tre
e
Dat
a/M
anag
emen
t
Pri
vate
Tre
e D
ata/
Mg
mt
Pro
act
ive
Man
agem
ent
Yea
rs o
f E
xpe
rien
ce
N
eed
ed
Ordinances $ X X X X 3 Management Plans $ X X X 2 Tree Inventories $ - $$$$ X X X X 1 i-Tree Streets Benefit Model $ X X X X X 1 Hyperspectral Imaging $$$$ X X X X X X 5 Urban Tree Canopy
Analysis $ - $$$ X X X X X X 3
1 The cost is most often associated with project size and detail. This pricing is based on current, average industry costs; $ = <$5,000; $$ = $5,000-$15,000; $$$ = $15,000-$25,000; $$$$ = >$25,000.
Community OutreachOutreach and education to citizens, elected officials, businesses, and other community stakeholders is a key factor in successfully managing exotic and invasive pests. The ability to map the threat and demonstrate the value of the urban forest is an integral part of an educational program.
Management ToolsThis project did not evaluate all available urban forestry management tools that can be used to manage exotic and invasive pests. Each community should research these tools as well when preparing a response to these threats.
A Tale of Four CitiesEvanston, Skokie, Wilmette, and Winnetka all have chosen similar urban forestry management tools – some simple and some advanced – to help understand and manage the threat of exotic and invasive pests. With the results of this study, these communities can now compare the effectiveness of these tools, share management strategies and better understand the threats to their urban forest, and create a multi-faced response that best serves the needs and conditions of the community and forest.
What’s NextThe goal of this project is to assist other communities to better understand what tools are available for assessing the threat of exotic pests. The next step is to promote and share the results of this project.
For More Information
Illinois Department of Natural Resourceswww.dnr.illinois.gov
U.S. Forest Service, Department of Agriculturewww. fs.fed.us
USFS i-Treewww.itreetools.org
Contact Josh Behounek ([email protected])www.davey.com
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