Seven trees in Chesterton’s Dogwood Park have been invaded by the emerald ash borer, an exotic beetle known to kill entire ash trees.

Arborist Russell Hodge said he suspected an infestation while at the park in late summer. Then he noticed the damage to the ash trees one day in December while driving by the park. Hodge, who lives nearby in Portage, returned later to inspect the trees. He said he found an active infestation in four ash trees and suspected an infestation in a few others.

One of the trees is likely already dead and others probably cannot be saved, said Hodge, a certified arborist with the International Society of Aboriculture.

Chesterton Park Superintendent Bruce Mathias said it’s since been determined that a total of seven trees have been infested on the southeast side of Dogwood Park.

“There’s nothing we can do at this point. They’re far gone enough where I can’t save them. So we’ll cut them down and plant new ones straight down the line,” Mathias said.

Hodge said it is believed that the sighting at Dogwood Park is the first time that the pest has been confirmed within town limits. The Indiana Department of Natural Resources first established Jackson and Portage townships as infestation areas in November of 2008, and last November, designated the entire county as an infestation area. But the infestation in Dogwood Park is the first known within town limits, he said.

The emerald ash borer is an exotic beetle that feeds on ash trees, killing branches and even entire trees. The beetle was first discovered in southeastern Michigan in 2002, and less than two years later, it was confirmed in Indiana, according to the DNR.

Hodge, owner of Hodge Tree Care, said preventative measures are the best way to prevent further infestation.

But he also said the long-term treatment is not cheap due to the need to reapply treatments.

“This is something that’s a long-term management decision,” he said. “Fortunately there are not that many ash trees in Dogwood Park.”

Hodge said that if a tree is infected with an emerald ash borer, it does not necessarily have to be cut down. If there are other major defects, the tree is probably not worth saving. But healthier trees can be treated. He also said that generally, trees within a 10-mile radius of a known infestation should be treated as a preventative measure.

He added that with spring around the corner, the beetle will likely get active again and the damage to the ash trees may continue for more than a year. He said that one of the most severely damaged trees at Dogwood has probably been infested for two or three years.

“Even the largest of trees won’t survive past three seasons” of an active beetle infestation, he said.

Mathias said new trees will be planted to replace the infected ones “funds and time permitting.”

The species of new trees has not yet been determined, he said, but they will be of a species not susceptible to the emerald ash borer.

Posted 3/4/2010