By Liz Crampton

Guardians of the Forest

How a tiny bug is destroying millions of acres of our forests

Guardians of the Forest
How a tiny bug is destroying millions of acres of our forests

In a vast unfolding, hemlock trees stretch for thousands of acres up and down the East Coast, from small pockets in southern Georgia to vast forests at the tip of Maine. They push up from the understory, extending more than 100 feet toward the sky. Below exists a complex civilization of plants, insects and animals. Referred to by scientists as a keystone species, hemlocks are protectors of the forest.

Despite enduring for hundreds of years, Eastern hemlocks are at risk of destruction. Scientists estimate more than half of the hemlock forests in North Carolina, which blanket the Appalachian Mountains in the western part of the state, are dead or dying. The culprit? A miniscule pest, the hemlock wooly adelgid, which is only about the size of a period.

The adelgid has already destroyed millions of acres of hemlocks. And without the trees that tower above the forest, the complex network of plants and animals that depend on the hemlock for life could also be at risk of devastation.

Researchers across North Carolina have been searching for a way to stop it before it’s too late. At N.C. State University, etymologist Fred Hain and his team might be getting close.

“I think we’re close to becoming completely convinced that we can do this,” Hain said.

“I’m still confident that we can.”

Hemlocks Bluff Nature Preserve in Cary. Photo by Chris Conway.

It’s suspected that the adelgid, an aphid-like insect, hitchhiked onto Japanese shipping crates en route to the U.S. in the 1950s. The pest was first found on the West Coast, where it attacks Western hemlocks but doesn’t kill them. It took about a year for the adelgid to migrate to the East Coast to feast on Eastern and Carolina hemlocks. While the devastation is widespread, hemlocks in the South are suffering the most. Legions of adelgids have infested nearly all Appalachian hemlock stands south of Virginia in just a decade.

Adelgids latch onto the base of hemlock needles, sucking sap and nutrients from the tree. Once a tree is infected, it can die in as little as four years. Hain likens the adelgid infestation to European colonists landing in America and infecting Native Americans with smallpox.

“You can hardly go into North Carolina stands to find healthy (hemlock) trees,” Hain said. “There are not very many of them around. Most of them are dead or dying.”

Hain worked in the etymology lab at North Carolina State University for 40 years and is leading research that focuses on battling the hemlock woolly adelgid. He’s a straight-backed scientist who explains complicated environmental issues matter-of-factly. When asked why he’s devoted his life to study pests, he simply replies “genetics.” At 68 years old, Hain has spent innumerable hours in a laboratory — evidenced by his thick prescription glasses that hide faded blue eyes and frame a salt-and-pepper beard.

Scientists and environmentalists can take several approaches to fighting an invasive species: introducing biological predators, applying pesticides, preserving gene pools and breeding resistant hybrids. Yet no option is entirely foolproof or feasible.

Robert Jetton, another etymologist at N.C. State, said pesticides can eradicate adelgids, but it’s logistically impossible and too expensive to treat the entire Eastern hemlock forest. In addition, widespread pesticide use is ecologically and socially unacceptable, he said.

“The days are gone where they could just take airplanes full of insecticides and spray them all over the forest,” Jetton said.

Hemlock preservation has thus centered on the idea of restoration, rather than fighting a losing battle with adelgids. Hain has led research into breeding a resistant strain of Chinese hemlocks with Eastern and Carolina hemlocks.

“I’ve always felt that once we detect (invasive species), once we know they’re there, it’s already almost too late to stop,” Jetton said. “Not that we can’t come up with a solution, but it’s too late to stop the wide-scale destruction.”

Hain believes scientists are close to successfully breeding a resistant hemlock. Close is a relative term. It may take as many as 30 years, he said.

And in 30 years, hemlocks might be gone.

That’s where Jetton comes in. He heads Camcore, an international tree-breeding nonprofit headquartered at N.C. State. For hemlocks and other threatened tree species, the organization preserves trees’ gene pools by collecting seeds and growing trees in sheltered artificial environments. This way, if the hemlocks were to die out in the wild, preserved trees will be on standby. They also serve as a base population for breeding.

It’s estimated that invasive species cost the nation $120 billion a year, according to Cornell ecologists. The federal government spent $2.2 billion in 2012 trying to control them and replenish the ecosystems they destroy.

Although the government has poured money into reversing the effects of invasive species through etymology research, funding isn’t substantial enough to keep scientists ahead of the game.

Hain said he grew frustrated with federal research funding shrinking, so he left the lab in 2010 to start a nonprofit organization. The Alliance for Saving Our Threatened Forests uses private funding to support research for eradicating pests, especially the hemlock woolly adelgid and the balsam woolly adelgid, which attacks Fraser firs.

“The money’s not there anymore,” Hain said. “I felt for some time that we need to tap into the private sector.”

A big part of the alliance’s following, Hain said, comes from supporters of the American Chestnut Foundation, which has had measured success in backing research that explores blight-resistant American chestnuts. In the early 1900s, a fungus wiped out billions of chestnut trees, which sparked a chain reaction that killed dependent wildlife species. Over time, research and advocacy support have revitalized the chestnut in Appalachian forests.

Hain said that if the lab discovers an adelgid-resistant hemlock during his lifetime, it would be monumental.

“It would mean I could die with the satisfaction I helped save the health of the American forest,” he said.

Hemlocks Bluff Nature Preserve in Cary. Photo by Chris Conway.

Tucked amid the commercial hum of Cary sits the Hemlock Bluffs Nature Preserve, a 140-acre stretch of hemlocks and other native plants. This pocket of hemlocks is unusual — most forests are located in the Appalachian mountains. But the preserve has a cool climate that’s ideal for Eastern hemlocks; the chillier temperatures are fostered by cold air that flows down from the bluffs.

The hemlock stands more than 100 feet tall and lives for hundreds of years. Intricate patterns are etched into its light mahogany bark. Hemlocks are found in the shade along bubbling streams and rivers.  

For some, trees are merely casual landmarks alongside a road, routinely ignored. But for others, they stand as a sacred symbol. In some cultures, a tree is the root of creation; Greeks believed the first man was made from an ash tree, and other northern Europeans thought man was born from an alder. A hemlock is one of the four primary trees of the gods in China — a country where warriors would tear down holy forests rather than destroying temples, as a symbol of conquest.

On a wintry late morning in January, the hemlocks in Cary are barren, stripped of their foliage. More than 100,000 people visit the preserve every year, many of which are families with young children and runners accompanied by dogs.

In 2010, maintenance workers noticed clumps of white bugs dispersed around tree trunks. It was the hemlock woolly adelgid. They needed to act.

After weeks of research and countless meetings, the town of Cary, which sponsors the preserve, decided to apply a pesticide treatment. The preserve’s small scale afforded the luxury of using insecticides, although it was costly. Treatment was $9,000, and bi-annual checkups cost $3,000 to make sure the pest hasn’t returned. The preserve was temporarily shut down while workers handpainted a pesticide on the trunks of the preserve's more than 200 trees. The pesticide has a low toxicity and wasn’t absorbed into the soil or water.

It appears the adelgid is gone for good from the hemlocks, said Mark Johns, nature program specialist at the preserve. It’s an example of an eradication process that works, a success story. Johns stressed the importance of going to great lengths to preserve the environment because, ultimately, everything is connected.

“It’s like saying, ‘Let’s do away with the owls,’” Johns said. “You can’t say that.

“You always want to do your best to protect the relics.”