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Beetle battle in Georgia's forests

Thousands of acres of hemlock forests across North Georgia are under attack

POSTED: October 18, 2009 12:49 a.m.
University of Georgia photo/For The Times

This tiny pest, the woolly adelgdid, attacks both eastern (Canadian) and Carolina hemlock trees, which often are damaged and killed within a few years of becoming infested. The infestation of the woolly adelgid is now established from northern Georgia to southeastern Maine and as far west as eastern Kentucky and Tennessee.

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Chuck Gregory recently wondered what it must have been like to experience a forest of thick-bodied American chestnuts.

Once a staple of the north Georgia mountains, a blight virtually extinguished the chestnuts in the early 20th century.

"We never saw a chestnut forest," said Gregory, the resource manager for Georgia State Parks.

Gregory marveled that such a predominant hardwood could completely disappear, he said.

"We’ve never seen a chestnut forest," Gregory said. "And it was all over this part of Georgia."

The thought reminded Gregory of the Eastern hemlocks flanking Georgia’s mountain streams, all of them waiting in line to join the chestnuts.

"In our lifetime — in our grandparents’ lifetime — it’s like wow, we are seeing entire species decimated," Gregory said.

Of a quarter-million acres of Eastern and Carolina hemlocks in Georgia, nearly all are infested with the hemlock woolly adelgid, according to forest health specialist Scott Griffin.

Each year, thousands of adelgids tuck into the hemlocks’ evergreen boughs and suck their starchy sap until the tree is too weak to survive.

The U.S. Forest Service predicts that nearly 90 percent of Georgia’s hemlocks will die this way in the next 10 years.

Over the last decade, the woolly adelgid has made the Chattahoochee National Forest its home. The insect native to Japan can be found in nearly all of North Georgia’s state parks.

Today, the adelgid has moved from Rabun County as far west as Murray County. The only hemlocks in Georgia that have not been infested are those in Dade County, in the far west corner of North Georgia.

When Forest Hilyer, chairman of the Lumpkin Coalition, discusses the hemlocks, there is a growing sense of urgency in his voice.

"Literally, the clock’s ticking right now," Hilyer said. "I mean, we’ve got four to 10 years before you start seeing major, major damage in all of North Georgia’s hemlock ranges."

"... Whatever we’re going to protect needs to be protected now."

Hilyer helped start the Dahlonega-based Lumpkin Coalition in 2005, and though the organization has a broad purpose, most of its efforts have been geared toward saving the hemlocks.

The group helps private property owners treat infested hemlocks, and for the past five years, the coalition has sponsored a music and education festival to raise awareness and money to support the agencies fighting the woolly adelgid.

One of the beneficiaries of the Coalition’s work has been Paul Arnold, a biologist at Young Harris College.

Arnold was the first researcher in Georgia to begin raising a tiny ladybird beetle that is one of the adelgid’s few natural predators. The two insects have evolved so closely in their native Japan that the beetle’s survival depends solely on the adelgid.

Since Arnold set up the first breeding site for the beetle in 2005, two other colleges — the University of Georgia and North Georgia College & State University — have begun working with Arnold to breed the beetles.

To date, the three sites have released between 160,000 and 170,000 beetles in north Georgia’s forests, Arnold estimates.

There are signs that the beetles are successfully reproducing in Georgia’s forests, but Arnold said researchers have not gathered enough data to know if the army of beetles they are breeding will be a great enough force against the adelgids.

"Maybe the beetles are doing some good, but I would not be able to look anybody straight in the eye and say that, for sure, I know that they are," Arnold said.

And since they are still wary of the forcefulness of the biological control the beetle may provide, most agencies managing the state’s forests are supplementing their biological efforts with chemical pesticides.

Most commonly, hemlocks in Georgia are treated with a synthetic chemical called imidacloprid, Arnold said. When it is injected into the soil near a tree, the nicotine-like chemical will protect a hemlock from the woolly adelgid for about five years.

And while the chemical is guaranteed to buy the hemlocks some time, its safety to the environment is not completely guaranteed.

Both Germany and France banned imidacloprid after finding it was responsible for the deaths of honeybees there, according to a 2008 report in the major British newspaper The Guardian.

A group of beekeepers in North Dakota sued Bayer Corporation, the company that produces imidacloprid, blaming the chemical for the loss of thousands of honeybee colonies in 1995, according to a report on the Institute for Southern Studies Web site.

Arnold said he has not yet seen that injecting imidacloprid into the soil has caused any harm to honeybees here, but "I would say all bets are off if we decided to spray the stuff on the tree," he said.

And though the Environmental Protection Agency considers the chemical a "potential" water contaminant, it has been the go-to, guaranteed product for treating adelgid infestations in Georgia.

Between 2006 and 2008, the U.S. Forest Service treated approximately 7,200 hemlocks in the Chattahoochee National Forest with imidacloprid, McKenzie said. The Department of National Resources also uses the chemical to treat trees on state park lands. The Georgia Forestry Commission and the Lumpkin Coalition routinely lend imidacloprid injectors to homeowners who want to treat infested trees.

"We still don’t know if we’re causing a bunch of damage with chemicals or we’re causing a bunch of damage with beetles," Hilyer said. "But still, everybody’s on that same page of we’ve got to do something, because losing the hemlocks is going to be so bad."

If the hemlocks in Georgia die, it would impact hundreds of birds, fish and insects that depend upon the trees, said Karen McKenzie, a public affairs officer for the U.S. Forest Service.

Without the shade that hemlocks provide mountain streams, water temperatures will rise and jeopardize the streams’ trout and crayfish.

Approximately 500 species of insects depend on the tree, and 90 percent of wood thrush nest in hemlocks, according to the University of Georgia’s Wahsega 4-H Center Web site.

"It’s an important component of our ecosystem," McKenzie said. "You definitely don’t want to lose something that’s widespread in your forest."

But the army of adelgids so far outnumbers the people trying to fight them that, even on two fronts, chemical and biological, the battle is overwhelming.

"I don’t know if you do catch up, honestly," Gregory said. "It’s an issue that’s bigger than anybody or anything. The (Lumpkin) Coalition, the U.S. Forest Service, Georgia State Parks service will not have the financial resources to totally address this problem. ... There is way too many trees that are infested that could possibly ever be treated."

Devastation from adelgid infestation is already visible in Rabun and Towns counties, where the aphid-like insect first entered Georgia earlier this decade. There, entire stands of hemlocks are now left as towering skeletons.

Still, Gregory said he feels good about the work DNR has done to fight the adelgid.

The Georgia Forestry Commission has helped DNR obtain grants through the U.S. Forest Service that help pay for the expensive chemicals to treat the trees.

At a time when state revenues hardly pay for staff salaries, the teamwork between the agencies has allowed DNR to treat most of the "legacy" trees at the state’s parks and protect the rare Carolina hemlocks at Tallulah Gorge, Gregory said.

To fill the need for human resources, the Forest Service and DNR have begun incorporating volunteers in their efforts.

The Forest Service allows volunteers to treat trees in the National Forests as long as they coordinate with district rangers first, said McKenzie.

DNR recently started a pilot program that allows members of "Friends" organizations to adopt and monitor treated hemlocks at Smithgall Woods and Unicoi State Park, both in White County.

But even those most intimately involved in the cause worry that, despite all the efforts, the hemlocks may be lost.

Gregory, McKenzie and Griffin, who works for the Georgia Forestry Commission, all describe their work as if it were damage control.

And increasingly, the hemlock is compared to the long-lost American chestnut.

"I’ve heard the hemlock compared to the chestnut," Griffin said. "But the difference is there is something you can do to save those hemlock trees. There are individuals that can do something to save the trees that are important to them."

But even Griffin is hesitant to say that the hemlocks can be saved.

"I guess time will tell," he said. "The adelgid’s doing pretty well in the southern United States. ... The potential for it to spread is just limitless, for the most part, at this point."



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