Why did we move to a three year treatment schedule?

When we began HOLS SYA in 2021 we decided to follow the two-year treatment schedule recommended on the label of the gold-standard insecticide our arborist recommended, emamectin benzoate. That meant the ash would be treated in 2021 and the next cycle would be 2023. 

We ran a campaign again in 2023, successfully treating all treatable ash in HOLS boundaries. 

At the same time, we had been lobbying the city since 2021 to treat all of Chicago’s at that time approximately 85,000 street ash trees. We had some success in that, due to our lobbying, in 2024 the Bureau of Forestry (BOF) treated 15,500 street ash in wards around the city. However, the untreated trees are on a path to die in the next several years and Forestry does not have funds at this time to retreat the treated ash when they are due in 2027.

About 45 of the ash BOF treated in 2024 were HOLS trees we had treated in 2023, which our arborist had clearly identified with dated treatment tags nailed to the tree. In other words, the city used tax dollars to unnecessarily treat our ash trees that did not need to be treated for another two years.

As mentioned, the first treatment recommendation in 2021 was for a schedule of every two years. Now the leading experts in the field, Purdue University, state that “once every 3 years is enough to keep ash trees alive.” (1)

To make the campaign schedule manageable for us as volunteers we have decided to treat those BOF treated trees in 2026 in order to get them on schedule with HOLS trees. It is not feasible for us as volunteers to get on a cycle of fundraising and treating them in staggered years. 

There are 45 BOF treated trees (2 yr. schedule for this cycle). There are over 250 remaining trees in the HOLS area on the 3 yr. cycle. Going forward, after this 2026 treatment the next HOLS campaign will be for all of them in 2029.  

We recognize that this solution is not perfect. Ideally, BOF would have consulted us on our preferred options. BOF would not have used taxpayer money on trees that did not need it at that time. This plan is what will allow us to save the ash and save ourselves from burnout. We hope you agree with our reasoning. If not, please wish us well anyway in our effort to save HOLS ash trees when the city will not be doing that.

We always have a fund for the trees most in need. The 45 BOF treated trees will not receive those funds, so if they are not sponsored they will not be treated. There is a chance that due to most, possibly all, of the ash trees near them being treated they may benefit due to a reduction in the local EAB population and not be affected by EAB for an additional year, 4 years instead of 3, at which time we plan another treatment campaign. We cannot say for sure that would happen and recommend that if you have one you care about you sponsor it for treatment.

(1) According to Purdue University, the leading experts in the field, "Research clearly shows that treating trees once every 3 years is enough to keep ash trees alive. Increasing the time between treatments beyond 3 years will increase the risk of losing your trees." Posted on May 12th, 2023 in Forests and Street Trees, Invasive Insects, Urban Forestry