By Ketul PatelThe Daily Northwestern

Unlike those of their neighbors in Wilmette, almost all of Evanston’s ash trees are safe for now.

The Village of Wilmette recently announced it would remove all of its nearly 2,900 publicly located ash trees over the next five years after it discovered some were infested by the emerald ash borer beetle.

The exotic insect originated in Asia, where the beetles only attack diseased trees. However, the beetle can attack healthy ash trees in North America because North American ash trees do not have built-in resistance to the beetle, according to the Purdue Entomology Extension at Purdue University.

The adult beetles eat the foliage and cause little damage to the trees, but the larvae eat the inner bark of the ash tree, damaging its ability to transport water and nutrients.

The emerald ash borer was first discovered in the United States in the Detroit area in 2002. Infestations have since been found in parts of Ohio, Indiana and the Chicago area.

Douglas Gaynor, director of the Evanston Department of Parks/Forestry and Recreation, said he does not plan to remove the city’s healthy ash trees.

“At this point, I’m not willing to take down all the trees,” he said. “We’re still looking into (our options).”

Gaynor said a survey conducted last summer found that a “little less than a dozen” ash trees in Evanston have been infested by he beetle.

Several of the trees were removed as part of a training exercise, Gaynor said. The rest of the infested ash trees will be removed before the summer.

There is no known way to prevent the infestations or to treat infested trees, Gaynor said.

He said the beetles are in a dormant stage and will remain so until the end of April or early May, depending on the weather.

Evanston has about 4,000 public ash trees, which make up about 12 percent of the city’s tree population, Gaynor said. The city stopped planting ash trees in 1999 due to a policy to prevent one species of tree from being overrepresented in Evanston’s tree population.

Warren Goetsch, division manager of natural resources for the Illinois Department of Agriculture, said removing the ash trees was an appropriate response for Wilmette because it is a relatively small town. Its size could facilitate the spread of infestation faster than in larger areas where the ash trees are more sparsely planted, he said.

Goetsch said the state does not recommend these measures for all towns.

“Each village is going to be faced with its own decision,” he said. “Other cities that don’t have current infestation or are further removed from the infestation need to be carefully watching their ash population.”

But Virginia Mann, an Evanston resident who co-founded To Rescue Evanston Elms in 2002, said she would like to see a regional approach to deal with the infestation.

“I think there has to be a comprehensive plan by region,” she said. “Evanston and Wilmette can remove the ash trees, but it won’t make a difference if Chicago or Winnetka don’t remove them.”

Mann said Evanston will have to remove the ash trees anyway since there is no environmentally friendly way to save the ash trees from infestation.

“Our ultimate goal is to save the most trees possible,” she said. “Sometimes we have to sacrifice some trees.”

Reach Ketul Patel at [email protected].