Saving Tennessee's Majestic Hemlocks
Private Gifts Fuel Effort to Save an Ancient Species
In the forests of Southern Appalachia, a battle is raging—one brought on by global trade and advanced by winds, migratory birds, and humans. It is a battle that might have been lost before it began had it not been for gifts that seeded the project.
Foresters and scientists are fighting an invasive pest that threatens the eastern and Carolina hemlocks. Hemlocks can live over 900 years and reach heights of over 165 feet. The trees are critical to the biodiversity of the Great Smoky Mountains National Park, the Cherokee National Forest, the Cumberland Mountains, and the Cumberland Plateau. Once gone, no evergreen species exists to replace them.
The challenge for scientists is to save what hemlocks they can to conserve the trees for future generations. To do that, foresters and researchers are using every tool at their disposal. Those tools include tiny beetles being reared at the Lindsay Young Beneficial Insects Laboratory at UT’s East Tennessee Research and Education Center in Knoxville. The beetles’ job is to devour a pest so tiny it can barely be seen with the naked eye, yet so lethal it can bring down one of the nation’s mightiest trees.
The hemlock woolly adelgid, an aphid-like insect that feeds on sap, has moved through the Southern Appalachians like wildfire, according to Rusty Rhea, a UT graduate and forest entomologist with the Forest Health Protection program of the U.S. Department of Agriculture Forest Service.
In cooler climates, this Asian pest can take seven to 14 years to kill a tree. In the Southeast, however, the adelgid kills trees in roughly five years. Because eastern species of hemlock have no natural resistance, the trees will eventually be extinct in Southern Appalachia without our intervention.
Before the insect moved into Tennessee forests, the USDA Forest Service had already identified and collected beetles to fight the adelgid, but there were no facilities in Tennessee adequate to raise beetles. That is where the University of Tennessee and regional donors stepped in to help.
An early grant from the Friends of the Smokies organization kick-started the rearing process in 2004. Then the Friends launched a targeted effort to help UT build a bigger, better space for beetle production. The result? A four-building complex of laboratories has raised almost 440,000 beetles to date—funded by private gifts.
Private money to renovate space came from the late, noted Knoxville philanthropist Lindsay Young and North Carolina’s Mr. and Mrs. Fred Stanback. The new facilities enabled UT to use funds provided by the National Park Service, USDA Forest Service, state of Tennessee, and Tennessee Agricultural Experiment Station. Recent gifts from Partners of the Cherokee, Ripshin Lake Corporation, and the Stanbacks have allowed the laboratory to significantly improve production capabilities.
Two beetle species, Sasajiscymnus tsugae (also known as St) and Laricobius nigrinus, are reared at UT. “The Forest Service challenged us to produce 200,000 adult St beetles this year, which was more than double what we’d done in the past. We ended up producing over 213,000. With Laricobius, we were challenged to produce 20,000 adult beetles, which was about 10 times the number produced last year. Resources acquired from private gifts played a huge role in our success,” says laboratory director Dr. Pat Parkman.
Pesticides are also being used to combat the adelgid, but Rhea, Parkman, and others believe the beetles are critical to conservation efforts. No matter what, scientists cannot save all the trees. But thanks to the generous support of UT donors, we have the chance to conserve an important and beautiful species for future generations.
