Hemlocks - NC State Saving Seeds

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BREVARD - Forest insect researcher Robert Jetton stopped the van near a stand of eastern hemlocks in Dupont State Forest when he saw what he was seeking: tiny seed cones that could save the evergreens from extinction.

The slow-growing eastern hemlock, a pillar of Appalachian forests, grows 150 feet tall and lives 700 to 800 years. But a tiny exotic pest, the hemlock woolly adelgid, is devastating the trees. It has left forests of dead and dying evergreens from New Jersey to North Carolina. The gray trunks of lifeless hemlocks -- many of them centuries old -- stand like ghosts in the mountains.

Jetton, 32, and Andy Whittier, 31, work for CAMCORE, an international tree conservation program at N.C. State University. On a crisp mountain morning, they make an unlikely rescue team, bearing limb pruners and cloth sacks. They collect seed cones to transplant two threatened species to South America and save them from a rampant pest in this country. This fall, they have harvested cones from 36 eastern hemlocks in North Carolina, Virginia and Tennessee and 11 Carolina hemlocks, an extremely rare species, in South Carolina, Tennessee and Virginia. The cones should yield about 20,000 Carolina hemlock seeds and roughly 100,000 eastern hemlock seeds.

"We're really the Johnny Appleseeds of the world," said Bill Dvorak, director of CAMCORE, which was founded in 1980 to conserve threatened tree species in Central America and Mexico. The cooperative has expanded and now counts among its members timber companies in 15 countries that pay dues and receive technical assistance.

The work with Carolina and eastern hemlock species is CAMCORE's first effort to protect species in the United States, under a four-year, $395,000 contract with the U.S. Forest Service. "If we lost all the hemlocks here," Dvorak said, "we still would have pockets of these in other countries that we could replant."

The disappearance of the hemlock from Appalachian forests could have drastic effects on the ecosystem. Anyone who has camped by a creek in the Southern mountains has probably pitched a tent beneath hemlocks. Fishermen who have stood knee-deep in a fast-flowing trout stream have enjoyed the tree's deep shade, which keeps creeks cool and provides habitat for fish.

The adelgid, a tiny aphidlike insect that arrived on nursery plants imported from Asia, is present in 16 Eastern states. CAMCORE says it has infested hemlocks over 50 percent of their growing range. Infested trees typically die in about four years.

The pest, first confirmed in North Carolina in the mid-1990s, has spread into Great Smoky Mountains National Park, Joyce Kilmer Memorial Forest and Linville Gorge. Jetton said he has seen more evidence of dead trees in North Carolina in the past two years.

"The trees have started to decline so rapidly," said Jetton, hemlock program manager for CAMCORE and a doctoral student in entomology. "Our approach this year is to collect what we can [as] a hedge against the worst-case scenario."

Collecting cones is one of several Forest Service strategies to preserve the hemlocks. The agency is also cultivating and releasing species of beetles that eat the adelgid. But it will take several years to determine whether the beetles are slowing the adelgids' spread.

"Given the rate of decline we're experiencing in the Southeast, we want to make sure we have the potential to work with hemlocks later," said Rusty " Rhea, an entomologist with the U.S. Forest Service in Asheville. It's an insurance policy.

"Those are top-notch guys doing something hardly anybody in the world does."

Collecting cones

Some hemlocks don't produce cones each year, so the CAMCORE staff searches for trees that have cones, then tracks their ripening. A given tree will produce a sizable cone crop every two to six years.

"We were here two weeks ago, and the cones were just too green," said Whittier, standing beneath a tree with thumb-size cones dangling from some branches. "They've ripened up well. We like to get them right when the scales are opening up but before they lose the seeds."

The timing is difficult. Some cones on a branch might already be open and others aren't ripe.

With a limb pruner, Whittier clips a few branches with cones. Then he puts the cones in a cloth bag the size of a flour sack.

"What tree number are we working on?" Jetton asks. Whittier, a research technician, gives him the number off a metal tag that will be tacked onto the tree.

"We tag each of the trees we collect so we can come back and do re-collection," Whittier explains. "We've had some trouble finding tagged trees in Linville Gorge that we think are gone already."

From North Carolina, the team moved on to Tennessee. Besides North Carolina and Tennessee, they have collected cones from South Carolina, Georgia and Virginia since 2003. They want to gather seeds in Alabama, Georgia and Kentucky to make the gene pool as diverse as possible. The goal is to collect seeds from 600 trees in 60 locations.

Insuring survival

A week after the excursion into the woods, Jetton and Whittier set about separating the seeds from Carolina hemlock cones harvested earlier in the fall.

At the Tree Improvement Laboratory at N.C. State, white cloth sacks of cones are stacked on a table like bags of money. Each is labeled with the tree's location: Cripple Creek, Va.; Cliff Ridge, Tenn.; Caesar's Head, S.C.; Dupont State Forest, N.C.

Jetton empties the sack of cones into a homemade wooden box with a screen on one side.

As the cones dry over a period of weeks, they open their scales to release the seed. The seeds, the size of a poppy seed, have tiny wings that allow the wind to disperse them in the wild.

Given a good shake, the seeds fall through the screen inside the box.

The mix of seeds and chaff are poured into a machine that works much like a hot air popcorn popper. It separates the seed from chaff by blowing air up through them. When Whittier turns on the blower, the wings and chaff dance in the column of air inside a clear plastic tube while the heavier seeds remain at the bottom. The chaff settles on ledges on the sides of the tube.

The seeds are collected in plastic bags. Some will be shipped later this year to a forest products company in Brazil to create a reserve stand of trees there, following a shipment a year ago. Some will be frozen for long-term storage at the National Seed Storage Laboratory, a forest service lab in Fort Collins, Colo.

About 3,000 Carolina hemlocks germinated from seeds shipped last year are sprouting in pots in a specially shaded research greenhouse at Arauco-Bioforest, a timber company in Chile that is a member of CAMCORE. In a year or two, when the seedlings are large enough, they will be transplanted outside in a tree plantation.

"This project is unique because ... we are helping the States to save a species," said Claudio Balocchi, genetic division manager for Arauco-Bioforest. "If something happens in the States, we will have the genetic material saved here so they can be reintroduced again. We are giving something back, trying to help you to preserve a native species."

Staff writer Wade Rawlins can be reached at 919-829-4528 or wrawlins@newsobserver.com.