Treat and preserve Chicago’s ash trees

Save Your Ash Chicago seeks to have funding in the 2023-2024 Chicago city budget sufficient to treat all of the treatable public parkway ash trees. Ash trees are about 12% of Chicago’s street tree canopy. As such, they are an essential part of Chicago’s green infrastructure. 

Protecting them from dying due to Emerald Ash Borer (EAB) is an investment in Chicago’s sustainability as we face increasing heat and flooding. It is fiscally, environmentally, and socially irresponsible to let them die and allow the services they provide, which can not be replaced for forty to sixty years (if newly planted saplings survive and mature), to be lost. 

Presence of ash trees in Chicago - 43,200 parkway ash

There are about 500,000 parkway trees in Chicago. (1)  There are now 43,200 parkway ash trees, as reported by Forestry, or about 12% of the parkway canopy.  Forestry stated in the RFP (2)  sec. 5.1,  “Emerald Ash Borer (Beetle) …  infests and kills all ash trees.”

It is not known how many are still in treatable condition, however in December 2022 Forestry reported the results of its ash tree survey the past summer. (3)  Of the 19,990 ash tabulated, or 46% of the total, there were 378 or <1.9% dead. This small percentage of dead ash is likely to indicate that a large majority are still treatable.

Importance of ash trees - Environmental, Social,  and Fiscal Responsibility

ENVIRONMENTAL

Trees provide numerous environmental and social benefits. Among them: regulating temperature and providing shade, filtering air pollutants, sequestering carbon, managing  and filtering rainwater, stabilize soils, maintain soil health, provide food and shelter for living organisms, improve resident’s mental, physical, and mental well-being, improve recreational options and aesthetics. (4)

In our rapidly heating, increasingly flooding city we cannot afford to lose these vital services if we want to retain and  build environmental and social resilience.

In 2012 Forestry appraised the value of each ash tree to be $5,899. (5)  Assuming that value is significantly higher in 2023 we can safely say each ash is worth $6,000 or more in environmental services. Therefore, Chicago’s 43,200 ash are worth about $259.2 M in environmental services.

Tree Planting Program

The previous mayor instituted a program of planting 75,000 saplings, which is an important aspect of maintaining our tree canopy. However, the mortality rate for saplings in an urban environment is high, in the first two years 34% and then 19% per year die, leading to half of them dying within ten years. (6)

The existing ash trees are 40 - 60 years old. Therefore, the newly planted saplings will not replace their environmental services for another 40 - 60 years.  

SOCIAL EQUITY

The city should treat all its parkway ash trees in the interest of social equity.

Mature trees are valuable to everyone, but we know some neighborhoods have the resources to save their ash trees privately, as Heart of Lincoln Square Neighbors Association and some other north side neighborhood associations have done, and some neighborhoods are under-resourced and do not have the means to do this. The city not treating all the ash will lead to greater inequity as ash trees die in some neighborhoods and not in others in the next few years. 

The green infrastructure of our city belongs to all of us. As such, we have a collective responsibility as a city to protect and preserve it. 

FISCAL 

Overview:

Treating the ash is urgent. Infected ash trees die within 3 - 4 years. (7) Since the ash have not been treated since 2018, and many since several years before that they are, without treatment, going to succumb to EAB at a greatly accelerating pace in the next two years. There is no choice but to remove a dead ash because it is extremely hazardous. 

The choice of treating the ash is significantly less costly than removing them, as it is estimated to be $4.32M every two years to treat them versus the alternative of costing the city and its taxpayers $43.2M to remove and replace within the next few years. Treatment can effectively prevent the need to remove them and therefore remain the fiscally sound choice for 20 or more years.

Rationale: Save and Protect Vs. Removal and Replacement

Save and Protect 43,200 trees:

Cost to treat one average size ash tree on a two year treatment cycle is $100 (8).

43,200 ash trees treated for one two year cycle = $100 x 43,200 = $4.32M 

Treated for 20 years (ten 2 year cycles = 20 years) = $4.32M  x 10 two year cycles  = $43.2M

Removal and Replacement: 

Cost to remove and replace a dead ash with a sapling is $1000 (9) or more. 

43,200 ash trees removed and replaced = $43.2M

Evidence Treatment Works

Milwaukee has been treating its 28,000 ash trees since 2008. Ian Brown, Urban Forestry District Manager, has stated in 2022 that since that time Milwaukee has not lost a single ash to EAB in that 15 years. Milwaukee treated its 28,000 ash trees every other year from 2009 to 2019, and since then every three years. (10)

The North Central Integrated Pest Management Center with leading EAB researchers from Ohio State, Michigan State, Purdue, and Colorado State published a bulletin in 2019 authored by well-respected EAB researchers. The bulletin addresses ‘How Effective Are Insecticides for Controlling EAB?’ 

They report that several studies show emamectin benzoate, which Forestry proposes using, provided excellent control of EAB for up to three years, even during years of peak EAB densities. (11)

Forestry RFP (Request for Proposal aka Contractor Bids) for Ash Treatment 2023 - Will not treat all ash trees

At present, the RFP Forestry has issued “only guarantees that 4,000 trees will be treated and preserved and the total after five years could be as little as 24,000”, said John Friedmann at the 8/8/23 Chicago Tree Equity Working Group meeting. Friedmann was discussing an addendum to the RFP. Friedmann pointed out that this plan will fall far short of the goal of preserving the ash, allowing most of them to die.

The RFP is limited by current funding, which we understand from Ald. Vasquez is $1M. However, if more funds are allocated for this project in the 2024 budget, Forestry can expand the RFP scope, said George Marquisos, Managing Director of the Chicago Infrastructure Trust, in the same meeting. 

How much funding is needed?

When bids on the RFP come in there will be a more precise number.  It is still possible to estimate from the current price the EAB certified arborist is giving the Heart of Lincoln Square Neighbors Association Save Your Ash campaign of an average of $100 per tree.

Using this price we show that

43,200 trees will be $4.32 M to treat for one two-year cycle.

There is $1M in the budget now, so the amount needed for 2024 is $3.32 M.

Solution 

• Treat all the city’s treatable ash trees in 2024 in order prevent further deterioration of infected trees and prevent further EAB infestation. 
• Going forward treat on a section by section rotating basis, similar to the Milwaukee plan.
• Continue to treat for at least twenty years while the newly planted saplings grow to a size that can provide similar environmental services that the mature ash do now.
• Evaluate the environmental, social, and fiscal benefits of protecting the ash on a yearly basis.

References

1. B. O. F. (n.d.). Forestry. City of Chicago. Retrieved August 15, 2023, from https://www.chicago.gov/city/en/depts/streets/provdrs/forestry.html#
:~:text=Chicago%20has%20more%20than%20500%2C000,the%20DSS%20Bureau%20of%20Forestry
2. 1257592: Emerald Ash Borer Treatment Services (Target Market)
https://drive.google.com/file/d/1Wa1lmANcqjuX0T-F_eLZEGhc6kBmFCX7/view?usp=sharing
3. Year End Report-Tree Equity Working Group_20221212
https://drive.google.com/file/d/1wBNzd_R5HLe0QYAx7ZtF7pJR1tlnjFfY/view?usp=drive_link
4. L. S. (n.d.). Servicing those ecosystems: The value of trees. Retrieved August 15, 2023, https://drive.google.com/file/d/1wBNzd_R5HLe0QYAx7ZtF7pJR1tlnjFfY/view?usp=drive_link
5. Forestry_EAB_Report_April-2012SYACCAnnotated.pdf https://drive.google.com/file/d/1noVJMKuah-nNYjlN1L7q1wWxGskulemM/view?usp=sharing
6. Nowak, D. J. (1990). Newly planted street tree growth and mortality. USDA Forest Service, US Department of Agriculture. Retrieved August 15, 2023, from https://www.fs.usda.gov/research/treesearch/18718#:~:text=After%20
the%20first%20two%20years,the%20species%20or%20between%20years.
7. Lovet, G. M. (2022, August 5). 8 billion North American ash trees at risk from emerald ash borer. Retrieved August 15, 2023, from https://www.caryinstitute.org/news-insights/feature/8-billion-north-american-ash-trees-risk-emerald-ash-borer
8. Using estimated cost from the Heart of Lincoln Square Neighbors Association Save Your Ash 2023 campaign. The campaign is not completed, however, preliminary figures are that for 347 ash of varying DBH the average cost is $100 per tree for a two year cycle. 
https://www.heartoflincolnsquare.org/save-your-ash?utm_source=Heart+of+Lincoln+Square+Neighbors+Association&utm_campaign=d8ebb90275-EMAIL_CAMPAIGN_2018_01_22_COPY_01&utm_medium=email&utm_term=0_156329d46d-d8ebb90275-30583371&mc_cid=d8ebb90275&mc_eid=0ad98d7f11
9. Forestry has reported at Chicago City Council hearings in 2021 and 2022 both a removal and replacement cost of $1,500 and of $1000. This example uses the lower cost.
10. Hanney, S. (2022, July 11). Save Your Ash: Citizen Efforts to Keep More Trees Alive in Neighborhoods. Streetwise Save Your Ash July 11-17,2022. Retrieved August 15, 2023, https://drive.google.com/file/d/1BLuWz0y4kzY-e1P0VohRB9-ntjY7Kzaj/view?usp=drive_link
11. Herms DA, McCullough DG, Clifford CS, Smitley DR, Miller FD, Cranshaw W. 2019. Insecticide options for protecting ash trees from emerald ash borer. North Central IPM Center Bulletin. 3rd Edition. 16 pp.
http://www.emeraldashborer.info/documents/multistate_eab_insecticide_fact_sheet.pdf