July 3, 2008

Caterpillars Clear Forest Of Trees

By PJ Reilly

Dave Henry figures the oak trees that dominate the hilltop off Pinch Road, just south of Mount Gretna, have been growing there for the past century.

In just the past two years, however, gypsy moth caterpillars have killed nearly all of them.

Seventy percent of the trees in this block of forest are oaks, said Henry, southeast regional forester for the Pennsylvania Game Commission. Ninety percent of them are dead.

Henry delivered his bleak diagnosis Wednesday morning during a media tour of a section of the 3,000-acre State Game Lands 145 in southern Lebanon County, just over the Lancaster County line.

The Game Commission is planning a timber cut and ground foliage elimination project on 53 acres of SGL 145 on the west side of Pinch Road at Mount Gretna Borough in an effort to re-establish the oak forest.

Except for a few oaks that are still living and some maples and tulip poplars left scattered throughout the tract, virtually all of the vegetation will be cut down or killed over the next year.

Then, 1,000 oak seedlings will be planted to jump-start regeneration of the forest.

I'm not going to lie to you. For the first year or two, it's going to look pretty bleak up here, Henry said. But in about five years, it's going to be so thick in here you won't be able to walk though it.

SGL 145 is not the only tract in the Furnace Hills that's likely to see such measures by the Game Commission to revive forests devastated by gypsy moth caterpillars the past two years.

After receiving reports from Game Commission foresters who surveyed several parts of southeast Pennsylvania by helicopter Tuesday, Henry said more tree-clearing projects will probably be scheduled for nearby SGL 156 and SGL 46 in northern Lancaster County.

We'll know for sure by the end of July if we have to cut trees in those areas, but quite frankly, I think you can count on it, he said.

Gypsy moth caterpillars have ravaged forests across Pennsylvania - including areas in Lancaster County, such as the Furnace Hills and Welsh Mountain - the last three springs.

The caterpillars eat the leaves off trees, which weakens them, making them susceptible to disease.

A tree can withstand one or two years of defoliation, but not three, Henry said.

Recognizing the damage the caterpillars caused on its three tracts of game lands covering some 14,000 acres in Furnace Hills in 2006 and 2007, the Game Commission paid to have sections of those properties sprayed by helicopter this spring with a biological agent that kills gypsy moth caterpillars.

Henry said the spraying seemed to help trees that were strong, but it couldn't save the weak ones.

There are only two stands of oaks on SGL 145, according to Henry. One is in the section of forest off Pinch Road that's scheduled for clear-cutting, and the other is off Route 117 west of Mount Gretna.

The rest of the forest is dominated by tree species such as maple, tulip poplar and birch, which do not produce mast for wildlife such as deer, turkeys and squirrels.

We need mast-producing trees in this forest to provide food for wildlife, Henry said.

If the Game Commission did nothing to the 53-acre tract marked for cutting, Henry said it would be taken over by invasive ground plants that would inhibit the growth of any trees.

It would be totally irresponsible for us to allow that to happen, Henry said.

So the agency plans to solicit bids from timber companies to begin cutting all the dead oaks and most of the non-oak trees on the 53 acres this fall. The trees will be sold.

Also, a contractor will be hired to spray the ground vegetation to remove all the ferns, grasses and invasive shrubs.

We have to take everything out so that the oak seedlings have a chance to grow, he said.

Henry will be watching the other stand of oaks on SGL 145, which also has been damaged by gypsy moth caterpillars, though not to the extent as the area off Pinch Road.

I'm remaining optimistic that it will survive, he said.

Meanwhile, plans are likely to be established for tree cuttings on 39 damaged acres of SGL 46, east of Fox Road, in Elizabeth Township and on 100 damaged acres in the southwest corner of SGL 156, north of the Pennsylvania Turnpike, in Penn Township.

While he said no decisions have yet been made on those Lancaster County tracts, Henry said cuttings there could begin before the end of the year.

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