This summer has seen an “exponential growth” in ash trees infested by the emerald ash borer on both public and private property in Lake Forest, according to City Forester Peter Gordon.
Since June 9, part-time forestry section staff have identified 1,780 ash trees on public property, with 1,172 tagged for removal on side streets, 573 tagged for removal on main roads, 145 in West Park and Northcroft Park, and 35 tagged in parking lots.
Another 142 ash trees were identified along Waukegan Road and five along Townline Road, both state roads owned by the Illinois Department of Transportation. Their removal is the responsibility of the state, Gordon said.
On private property, city crews have tagged another 3,702 ash trees.
“These trees pose a threat to the public health or safety or public properties,” Gordon said in his report to the City Council at its meeting on Sept. 2.
Figures show the city budgeted $200,000 in fiscal year 2015 for removal of damaged ash trees, with nearly 1,500 to be removed in all by a contractor, which is doing the bulk of the work, and city crews.
Removals are less than half completed and are far outpacing money available, Gordon said.
“Removing trees that are hazardous and dead will continue to be the main focus, followed by removing trees on main roads and then side streets,” he said.
To reduce contractual costs, the forestry section is attempting to remove 600 infested ash trees a year.
At the same time as the ash-tree removal is taking place, the city — like other municipalities — has to deal with diseased and dying trees of other species.
“A lot of people forget other trees are dying,” he said.
For ash trees not chemically treated against the borer infestation, the window of opportunity has closed.
“EAB has spread quickly,” Gordon said in his report. “Trees that have not been chemically treated have likely declined to a level where treatment is no longer a viable option.”
But those that have been treated are doing well.
The foresty section has identified approximately 650 trees that, because of their location or significance, were treated chemically, with 440 ash trees treated last year and 210 this year.
The cost for treatment this year is estimated to be just under $20,000.
Tree replacement is the last line of defense. By spring 2015, 660 trees of varying species will be planted to replace the lost ash trees.
“That’s right about our threshold — that we can actively maintain,” Gordon said.
For the types of trees to be planted, the city is “pushing natives and trying to get away from maples, because we have so many maples in town,” Gordon said. “We’re trying to diversify.”
A diversified tree inventory will help prevent large canopy loss caused when a single species suffers a catastrophic disease or infestation.
“Being able to locate and purchase them in large quantities has become challenging as more and more communities are diversifying their urban forests,” Gordon said.
This year, Lake Forest planted more than 38 species of trees throughout the community. The forestry section planted 367 trees in the spring of 2014 and is scheduled to plant 200 trees in the fall of 2014.
Based on current projections, ash tree replacement will continue through fiscal year 2021, replacing approximately 400 trees per year.
“This does not take in account other tree species that may need to be removed and replaced as a result of other insects, disease or natural causes,” he said.
Native Tree Sale
Where: Mellody Farm Nature Preserve, 350 N. Waukegan Road, Lake Forest
When: 8 a.m. to 1 p.m., Saturday, Oct. 18
Who: Lake Forest Open Lands Association and City of Lake Forest
Why: All trees will be sold at discounted prices and a portion of the proceeds will go to plant trees to re-green open city spaces. Pre-orders available until Oct. 16.