N.C. Region Races to Save Hemlocks

John and Jeanne Porter often hike at the Carl Sandburg Home National Historic Site in Flat Rock, N.C.

The towering hemlock trees are a common sight throughout the 264 acres, especially the lower 100 acres, including the trail leading up to the house.

But the trees are fighting a battle that, if lost, will change the face of the Sandburg property.

“It would be sad to lose” the hemlocks, said Jeanne Porter. “It would be painful not to have them.”

The trees are threatened by a tiny insect known as the hemlock woolly adelgid. And the problem goes well beyond the Sandburg boundaries. Private landowners, the national forests, the Blue Ridge Parkway and towns and municipalities are experiencing the infestation, which can kill the trees if they are left untreated.

“Each year we get a new infestation of (hemlock woolly) adelgids,” said Irene Van Hoff, forestry technician with the Carl Sandburg Home National Historic Site. “The treatments we’re doing really are killing them.”

Experts say if something isn’t done, the hemlock woolly adelgid could be the end of the eastern and Carolina hemlocks in Western North Carolina.

“It would really impact the visibility presentation of the park if all the hemlocks are destroyed. Especially the approach to the house,” said Jan Spicka, president of the Friends of Carl Sandburg at Connemara.

“We have hemlocks throughout the park. It would make a big difference” to lose the trees.

Under control for now
Van Hoff treats about 400 trees at the Carl Sandburg Home with a soil injection of imidacloprid, an insecticide the feeder roots absorb and move throughout the tree.

About 200 hemlock seedlings or saplings are sprayed with an insecticidal soap every year.

“The adelgids keep coming,” she said. “We have to keep treating because if we don’t, the adelgid population would be out of control.”

But with regular treatments that hasn’t been a problem, Van Hoff said. The trees are under control, and she’s not seeing them decline in health and vigor.

The hemlock woolly adelgid is native to Asia and is not a problem to hemlocks in Asia. It was introduced to the United States in the 1920s to the Pacific Northwest, and in the early 1950s to the Washington, D.C., and Richmond, Va., areas. Since it lacks natural enemies in North America, it has spread throughout the eastern United States causing damage to the eastern hemlock and Carolina hemlock.

Van Hoff said the adelgid was first discovered on the Sandburg property in 2001 or 2002.

“We have adelgids on just about every tree now,” she said. “When it first started, it was just on a few (trees). It’s pretty widespread now, but it’s under control.”

A tree that has not been treated and is infected with the adelgid will look needle bare and will become more and more transparent, Van Hoff said.

The Sandburg Home has a few trees that aren’t as green and have lost a lot of needles, but none have died yet, she said.

The Sandburg site spends about $10,000 a year on treating adelgids. That cost includes equipment, chemicals and labor, Van Hoff said.

Beyond the boundaries
The village of Flat Rock, which is just a short distance from the Sandburg home, is using soil injection to treat about 12 large hemlocks on the village’s 2.5 acres.

Flat Rock has hemlock trees scattered throughout the town, but the town has no jurisdiction over whether private landowners treat their trees or not, said Dave Bucher, Village Council member.

“There are a number of people in the village doing treatment, but there are probably a number who aren’t,” he said.

He said the village has tried to make people aware by putting information in the village newsletter.

The Great Smoky Mountains National Park uses a combination of methods to treat hemlocks, including insecticidal soap, soil injection and predator beetles, said park spokeswoman Nancy Gray.

But Rusty Rhea, entomologist with the U.S. Forest Service based in Asheville, said the future needs something more definitive.

“Chemicals are really short term and won’t give you prolonged protection more than a year or two,” Rhea said. People are “trying to develop something more environmentally friendly and long term in nature.”

Dim future
Chris Ulrey, plant ecologist with the Blue Ridge Parkway, said all the untreated hemlocks along the parkway are going to die in the next five to 10 years. The ones that have been treated will become the seed source, he said.

He hopes beetles will be in place by then and be able to control the problem. The problem now is the adelgids outnumber the beetles.

“The only way bio-control works is if the two are in balance,” Ulrey said.

He said when parkway officials released “Sassie” beetles, poppy seed-size insects imported from Japan, the hemlocks did not improve.

“We’ve only released one species,” Ulrey said. “We have to have a number of predator beetles released.”

Officials are researching other beetles, but they’re still behind the curve, Ulrey said.

“Until biological control is available and ready, we’re doing chemical control,” he said. “It’s a short-term, stop-gap measure.”

Other factors could contribute to the demise of the hemlock.

“If we were to get a really dry summer, we would see a lot of mass deaths of hemlocks,” Ulrey said.

He said people draw similarities between hemlocks and the chestnut blight, but when the chestnuts died, oaks filled in.

“We have nothing to take the place of the hemlock,” he said. “It will be a ripple effect when the hemlock goes. Streams will change, the whole ecosystem will change.”

A brighter outlook
Ulrey is pessimistic about the hemlock’s future because of the destruction he’s seen the adelgid do in Virginia and along the parkway, but others have a little more hope.

Patrick Horan owns 140 acres in western Transylvania County. This spring, he purchased and released 3,000 beetles. So far, he has been pleased with the results but said he will know more next year.

“Over the course of the summer I’ve been very pleased to see the trees growing new foliage,” he said. “It’s not a proven thing, but it seems to be promising.”

More than 3 million beetles have been released from Maine to Georgia, Horan said. The beetle was first collected in Japan in 1992, brought to the United States, quarantined and studied for three years. He said the beetle only eats adelgids and can’t reproduce without them.

“The adelgid doesn’t have a predator, so introducing one seemed like a good idea,” Horan said.

He said the beetles are very mobile and once a colony is established, they should spread out pretty rapidly.

Predator beetles have been released in old-growth areas of Great Smoky Mountains National Park with the hope that they spread on their own and reach remote areas, Gray said.

But the beetles are not something a small landowner could use to control the adelgids. Horan said the beetles need several acres to circulate around.

The beetles “won’t get rid of adelgids,” Horan said. “There will always be adelgid around, but they will cut (the numbers) down so they won’t do damage to the hemlock trees.”

Following suit
Officials from Brevard and Transylvania County are catching on to the “Sassie” beetle.

Jimmy Harris, mayor of Brevard, said the city has been gathering information on the beetles. In the meantime, workers have been chemically treating city property that has hemlock trees.

“To my knowledge (city) property has not been affected yet,” he said. “The ‘Sassie’ beetle is on our radar. We want to do all we can do to prevent the woolly adelgid from affecting our trees.”

Artie Wilson, Transylvania County manager, said the county is looking at a proposal to save the hemlocks at the Silvermont Mansion.

He said the county has a recommendation to the Board of Commissioners to buy 1,000 “Sassie” beetles for $2,300 for Silvermont. Some of the large trees at Silvermont were treated with a chemical injection about a year ago.

“We’re in the early stages of infestation,” Wilson said. “We want to see how this goes. There may be two other types of beetles that may help against the woolly adelgid.”

The Silvermont property has about 350 trees. The county would be partnering with Brevard College and North Carolina State University to see how effective the beetles are on the site.

“We’re trying to save the hemlock trees,” Wilson said. “If we don’t save them then we’ll have to take them down and taking them down is a lot more expensive than saving them.”

Landowners’ dilemma
The adelgid is a “popular topic to say the least,” Rhea said. “Most of the concerns are from private landowners who have hemlocks in their backyards.”

Rhea said his general recommendation for landowners is to use the chemical imidacloprid as a soil injection or treat trees with insecticidal soap to fight off adelgid until there is a better system for controlling it.

Ulrey said the insecticidal soap is a good option for landowners with small trees or hedges, but the trees have to be drenched with the soap every year for it to be effective.

Imidacloprid can be bought at hardware stores and costs about $1.25 per tree inch diameter.

“The key is continually checking the trees,” Ulrey said. The adelgids “can be hard to detect at first. By the time you see the white woolly masses, they’ve been there for a couple of years.”

The best time of year to treat for adelgids is in October and November when the weather starts to get cold and March and April when the weather starts to warm up, Van Hoff said.

Cliff Ruth, an agent with the Henderson and Transylvania County Cooperative Extension, said it might cost about $300 for a landscaper to treat a 20-inch diameter tree.

Doing it yourself may be cheaper, but the appropriate equipment and pesticides have to be bought, he said.

Whether to hire a landscaper or not would depend on each individual’s situation, Van Hoff said.

“If a person only has four or five hemlocks on their property, they could hire a local landscaper or arborist to treat the trees with soil injection,” she said.

Soil injection is the method of treatment the Forest Service recommends, Van Hoff said.

She said treatment could be expensive for people with a lot of acreage or a whole cove of hemlocks.

“It’s just going to depend on the person’s resources and how much they value hemlocks,” Van Hoff said.