Staff recommends injections to root out Dutch elm disease

Paul Thissen

If the Evanston City Council follows recommendations of city staff, about 1,300 public elm trees will be injected with anti-disease fungicide to prevent Dutch elm disease.

Dutch elm disease kills several hundred American elms in Evanston each year. The disease can be spread either by beetles that land on the tops of trees or through root grafts. When two elm trees grow within about 50 feet of each other, their root systems meet and graft together. The fungicide cannot prevent trees from becoming infected via the roots.

The recommendation would inject all “signature and standalone” elms. Standalone elms are trees that are not within about 50 feet of a privately owned elm. Signature trees would be those deemed especially large, old or majestic. Evanston has about 3,400 public elms.

This plan would protect more trees than any other city does, according to city staff research.

Injecting only signature and standalone trees would cost about $422,000 over the next three years. Injecting all trees, an option not recommended by staff, would cost just more than $1 million for the same three-year period.

The fungicide must be injected into the trees every three years to remain effective. Injecting a tree costs between $10 and $12 per inch of diameter — so injecting a tree 2 feet across would cost between $240 and $288.

The city already uses the “sanitation method” of preventing the spread of Dutch elm disease. During the summer months, when the disease can spread, two city employees work full-time surveying all the elms in the city to watch for the disease. If a tree exhibits symptoms, part or all of the tree is removed before the disease can spread into the roots where other trees might be infected.

“I think the (combination of sanitation and injection) would really make a good effort at prolonging the life of our elm trees,” said Doug Gaynor, Evanston’s director of Parks/Forestry and Recreation.

Though the city currently does not have legal grounds to inject trees on private property, it could pass an ordinance to require homeowners to inject the tree, Gaynor said. The city could pay for all or part of that injection. Some aldermen said they would oppose such a policy.

“I don’t support the city paying for private elm injections,” Ald. Ann Rainey (8th) said. “I think we’re going to have to be very careful and walk very softly on the issue of public dollars to inject private elms.”

Six Evanston residents spoke at the meeting to support a policy of injecting all of the elms.

“People move to Evanston for … the landscape, the architecture, the lakefront, and all those things are being eroded,” resident Deborah Hirshfield said.

Reach Paul Thissen at [email protected]