Emerald Ash Borers Could Decimate More Than 10,000 Lake Forest Trees

If you've seen an emerald ash borer attached to one of your neighborhood trees in Lake Forest, expect to see a lot more of the beetles in the coming years, according to Parks and Forestry Superintendent Chuck Myers and City Forester Peter Gordon.

"Before you start seeing the emerald ash borer damage, they've already been here three to five years," Myers told the Lake Forest City Council on Monday night. "We have removed over 125 infested trees. We are anticipating a huge increase in the next five to eight years."

While the city has fought Dutch elm disease for a while, the effects of the emerald ash borers are far different. The Parks and Forestry Department estimates that, based on previous tree inventory numbers, about 15,000 trees were lost to Dutch elm disease in Lake Forest over 20 years. Emerald ash borers, by comparison, are expected to decimate more than 10,000 trees in the next five years alone.

"I am estimating city parkways and all city property," Myers said. "Private residences would be higher yet."

Department workers are only tagging affected and diseased public trees with colored ribbons. Trees on private property are only tagged and a door tag placed on residents' doors (purple for Dutch elm, green for emerald ash borers) if the trees are a threat to public safety.

Workers will again begin tagging all affected trees next year. Myers said they are working with new computer software to set up a management system that will allow them to track trees and send mailings to residents.

Parks and Forestry staff plan to come back to the City Council May 17 with recommendations and plans for their next steps. They plan to start a new tree inventory and hope to hire more staff or interns to help with identifying infested trees. A five-year plan also is being developed and will be brought before the City Council in the fall.

The department has $20,000 budgeted and hopes to have that amount doubled. "We would like to get as much done this year as we can," said Myers.

The Chinese bugs, introduced to Detroit in 2002, since have been spreading steadily across the United States. After laying eggs, the larvae burrow into the tree and feed under the layers.

"They are eating machines," Myers said. "They're eating layers of bark."

Trees that are infested heavily then are drilled full of holes by woodpeckers seeking the larvae and can't be saved, but chemical treatment has been successful in treating trees in the earlier stages.

"Every ash tree is susceptible," Myers said. "Every tree will die unless it's treated."

The problem is long-term costs vs. replacements. Removal of just the public trees could cost more than $500,000, with replacement costs surpassing $2 million over five years. Those costs would be three to five times higher once other trees are added in.

Residents also will face costs in tree or plant replacements. The city is collecting information from local landscaping companies to be able to pass it on to residents.

"We are now looking at three to four landscape companies, and eyeing companies that have roots in Lake Forest, and getting prices," said Gordon.

Additional information, including details on the different insecticides and costs, will be added soon to the Parks and Forestry website.

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