Emerald ash borer: Small pest, big potential problems

The emerald ash borer is destroying Pennsylvania's ash trees and creating possible hazards in the process

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Ken Danchik noticed that the leaves on the ash trees in his wooded O'Hara back yard were thinning six years ago.

A quick Web search indicated that his trees might be infested with emerald ash borers, insects that feed on ash trees and were first found in Pennsylvania in 2007. Just a year after Mr. Danchik first read about the ash-ravaging insect, a number of the ash trees in his yard were clearly dying. By 2011, Mr. Danchik said, they were all "completely dead."

As ash borers continue to infest trees across the state, the number of living ash trees in the region is dwindling. Throughout parks, along streets and in private back yards, the trees are dying.

Pennsylvania at one point had 300 million ash trees. In 2005, roughly 400 of Pittsburgh'‍s street trees were ash, and now, "for the most part, they are dead or near death," said Matt Erb, director of urban forestry for the advocacy group Tree Pittsburgh.

Mr. Danchik had his property surveyed and his ash trees taken down two years ago, prompted by fear that they would fall on someone; children play in the woods and Mr. Danchik and his wife hike there. But he's worried that dying trees elsewhere pose hazards.

"I'‍m concerned about these trees falling," Mr. Danchik said. "We'‍re going to get a wind storm some day, and we'‍re going to get a whole bunch of trees coming down."

Lisa Ceoffe, a forester with the city, said she is not aware of any recent instances of ash trees falling on people or causing injury. Officials are working to remove potentially hazardous trees in parks and along roads and to respond quickly to complaints alerting them to problem trees, she said.

Still, Philip Gruszka, director of park management and maintenance for the Pittsburgh Parks Conservancy, said the area'‍s ash trees could be dangerous, especially those on private property if homeowners fail to take down the dead or dying trees in their yards.

Biology itself suggests that they could present a problem: Ash trees fall more quickly after death than many other trees, "the other kind of alarming side of the story," said Mr. Gruszka. A dead oak may remain standing for 10 to 15 years, while an ash will be on the ground in four years, he said.

When a dead ash tree is left standing its branches start to drop quickly, Mr. Erb said.

"They actually become hazardous as they'‍re dying," Mr. Gruszka said.

Officials are targeting dead and dying ash trees in areas where there is heavy foot traffic, Mr. Gruszka said. Treating infested trees is expensive, and when the ash borer came to the area, Mr. Gruszka said officials knew they had neither the budget nor the manpower to save them all.

City officials are conserving 158 ash trees in Pittsburgh. Removal is the safe option for others that might endanger pedestrians.

While municipalities can remove dead trees on public property, they can'‍t take down problem trees in private yards. Lisa Pawelski, Mr. Danchik'‍s wife, worries that many residents don't know their trees are diseased or that they have the potential to fall.

"The whole question revolves around whether the property owner knew [the tree] was diseased or not, which makes me even more eager to make sure this is common knowledge," Ms. Pawelski said. However, most people don't know, he added.

Mr. Gruszka said the Pittsburgh Parks Conservancy knew when the ash borer came to Pittsburgh that the "most important thing to do [was] to get the word out ... that this is coming, and that you need to be prepared."

Officials have held in-service trainings for employees who work in local parks to make sure that they know to be careful when mowing the lawn near dying or dead ash trees, for example, he said.

A problem in educating homeowners is that some might not even know they have ash trees, said Mr. Erb.

Residents with a number of large trees should consider having an arborist come out to assess them, he said.

Mr. Gruszka said dead ash trees will fall if they are not taken down. It'‍s only a matter of when.

"If they do nothing, the tree is going to fail. It will fall," he said. "If you don'‍t remove the tree as it's dying, it could fall over onto your garage, or onto your home, or on your neighbors'‍ home.

Madeline R. Conway: mconway@post-gazette.com, 412-263-1714 or on Twitter @MadelineRConway.

Madeline R. Conway: mconway@post-gazette.com, 412-263-1714 or on Twitter @MadelineRConway.

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