State College

Tree pest threatens ash population: Centre Region municipalities addressing emerald ash borer

Garry Williams is “really glad” College Township started treating ash trees two years ago for the emerald ash borer, an insect now devastating trees across the region.

The beetles feed under the bark of the trees, eventually killing them. According to the state Department of Conservation and Natural Resources, the EAB was found in North America in 2002 and has killed tens of millions of ash trees.

This year, the bug has been found in the Centre Region, and municipal staffs are planning for tree removal, chemical treatment or a combination. One of the telltale signs of a damaged tree is a trunk full of holes, caused by woodpeckers searching for the bugs.

Williams, the township public works director, said he has worked with Aikey’s Tree Service in Bellefonte to begin chemical treatment of College Township’s 415 ash trees on 24 public streets.

In 2012 and this summer, College Township injected the insecticide Imidacloprid directly into the soil at the base of the trees. According to a National Pesticide Information Center fact sheet, the chemical is “moderately toxic” if ingested and has a “very low” toxicity through skin exposure. This year, trees 15 inches in diameter and larger were treated by injection into the trunks, about 65 trees.

“I’m very pleased at this point with the treatment so far,” Williams said. “Our ash trees look great. We lost maybe two so far.”

Chemical treatments must be applied every year — or every two years for trunk injections — and College Township paid $18,000 last year and $22,000 this year to treat the trees. Williams said he will evaluate continuing treatment each year, and already placed it in the 2014 budget.

Ferguson Township took a different approach, choosing a removal and replacement program for about 600 varieties of ash trees. This year, the township removed about 120 trees and the program likely will continue three to four years.

Manager Mark Kunkle said the township is looking at $180,000 to remove and replace all of those trees.

“We’ve started with those ash trees that have actually just died and we have others that have been infected, but don’t show all the signs yet and will eventually die also,” he said. “We’re diversifying the street tree inventory and replacing with different varieties.”

Diversity is the key to addressing any tree diseases, including those that have sickened elm trees on Penn State’s campus and in State College, said Bill Elmendorf, chairman of the borough’s Tree Commission and associate professor of community forestry.

“With mono-cultures, you’re probably going to run into problems sooner or later,” he said.

The borough is working on a combination plan for its 350 ash trees on public streets, something arborist Alan Sam said staff has been preparing for.

“We stopped planting them about five years ago,” he said, adding that the borough is inclined to not use chemicals due to cost and time requirements.

After a quick review of borough trees, Sam said 27 declining ashes likely will be removed immediately. About 200 more will receive treatment or gradually be replaced.

“If it’s a healthy tree we may want to treat it,” he said. “There are a lot of iffy things about it.”

The borough also will work with the DCNR, which is providing a grant program to develop EAB management plans.

Harris Township is working with Elmendorf and its own Shade Tree Commission to determine a plan of action. Manager Amy Farkas said students will help conduct a tree inventory and determine how to address the ash trees.

Staff already has treated a 60-inch-diameter ash across the street from the township office in Boalsburg, in an attempt to preserve it. Farkas said it’s the largest in the township and is historically significant.

“You basically have to look at the value of the tree,” she said. “We don’t want to leave holes in our canopy. We’ll look at removal and treatment and try to put a dollar figure with that.”