Valley Forge Trail to Partially Close for Invasive Beetle, Emerald Ash Borer, Treatment

The emerald ash borer has a 99 percent kill rate once it inhabits a tree, experts say.

Upper Merion is taking the fight to an invasive beetle on behalf of millions of ash trees.

The Montgomery County township is going on the offensive as a bug called the emerald ash borer has already chewed its way through many parts of Pennsylvania, felling as many as 37 million ash trees in the last decade.

Arborists and state environmental officials are now warning residents and municipalities in southeastern Pennsylvania that the beetle is now in the region, and killing one of the most prominent tree species.

Upper Merion's assault on the beetles, in an effort to kill them before they kill ash trees along the Valley Forge West Trail at Heuser Park, will begin with an herbicide treatment beginning on Aug. 14.

The spraying is the first in a multi-step plan that will eventually include pre-treatment of non-affected ash trees, removal of diseased trees and eventual reforestation.

The initial step of herbicide spraying will take up to 10 days and the trail will be closed to the public during that time and in days following the treatment, Upper Merion said. 

The township expects the trail to re-open about Aug. 28. The timeframe could change depending on the weather and other factors.

"No visitors are allowed on the trail during the application and wait period," the township said in a statement Tuesday. "The safest bet for visitors to return to the trail once the application and wait period is over is after a heavy rainfall."

The emerald ash borer has a 99 percent kill rate once it inhabits a tree, experts say.

The emerald ash borer is native to Asia and arrived in the United States as long ago as the late 1980s. It was first discovered feeding on ash trees in the Detroit, Michigan, region in 2002. Experts now believe it was killing ashes for years before that.

How it got to the states is a good question, but it has traveled throughout much of the country in firewood -- the beetle is now found in at least 27 states, and still spreading.

“It’s in virtually every county in Pennsylvania,” Donald Eggen, the forest health manager for the Pennsylvania Department of Conservation and Natural Resources (DCNR), told NBC10 in May. “It’s been as simple as someone’s ash tree dies, and they say, let’s bring the wood up to the campsite. That’s how it spreads.”

At that time, Eggen said the state Division of Forest Health is in the midst of studying the ongoing prevention efforts in 10 towns, including West Chester, Philadelphia and Lancaster.

Eggen and local arborists said there are treatment options available to homeowners with ash trees, but it comes with a cost and must be done before a tree is infected by the beetle.

There are an estimated 2 million-plus ashes in the Philadelphia region.

An estimated 306 million ash trees make up four percent of Pennsylvania’s regular forests. (That doesn’t count the millions more in the state’s “urbanized” forests.) About 12 percent, or 37 million ash trees in state forests have already died at the pinchers of the emerald ash borer, which lays its eggs under the bark of the trees. The larva then eat their way along the inner bark and cambium of the tree, which cuts off nutrition and growth.

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