The ash tree could go the way of the American Chestnut in Pennsylvania -- into extinction.

State Agriculture Secretary Dennis Wolff and a panel of experts said today that the emerald ash borer beetle could wipe out Pennsylvania's ash tree population in 12 years.

That forecast, from the U.S. Forest Service, came during a press conference in Cranberry, where the invasive Asian insect with no natural predators in the United States was found in an ash tree Tuesday.

Surveys since Tuesday have confirmed the presence of thousands of the beetles within five miles of the first insect's discovery near the interchange of I-79 and the Pennsylvania Turnpike.

Mr. Wolff said Pennsylvania has 3 million ash trees valued at $760 million, not counting landscape and nursery stock.

"This is something we anticipated and we have watched, we knew it was coming,'' Mr. Wolff said.

On Wednesday, state officials ordered a quarantine in Allegheny, Butler, Beaver and Lawrence counties, restricting the transportation of all ash trees and materials, from nursery stock to wood chips. The quarantine will continue, Mr. Wolff said.

The emerald ash borer's larvae feed on the layer of wood just beneath the bark of the ash tree, cutting off water and nutrients and killing the tree. It has destroyed more than 20 million ashes in five states since it was discovered in the Detroit area in July 2002.

More details in tomorrow's Pittsburgh Post-Gazette.

First Published: June 29, 2007, 7:45 p.m.