Since slipping into the United States on nursery stock in the 1950s, a small insect called the hemlock woolly adelgid (HWA) has spread across the eastern United States. Though immobile as adults, their young hitch quick rides on wind, birds and other animals to infest new trees. HWA have killed 80-90 percent of eastern and Carolina hemlocks. Reaching sometimes more than 100 feet high and living for hundreds of years, hemlocks are keystone species in eastern forests. Removing them affects everything from soil pH to songbirds to animals swimming in forest streams.

Eastern hemlocks killed by the hemlock woolly adelgid in the Great Smoky Mountains. Photo by

Eastern hemlocks killed by the hemlock woolly adelgid in the Great Smoky Mountains.

In addition to hemlocks, another adelgid species, the balsalm woolly adelgid (BWA) tucked its deadly mouthparts into Fraser firs across the eastern United States. BWA has since infested every fir stand in the southern Appalachian Mountains, killing more than 90 percent of mature Fraser firs, North America’s most popular Christmas tree.

In 2007, a group of researchers across universities, the National Arboretum, and the USDA Forest Service, led by NC State University’s Fred Hain, convened to look for solutions to our continent’s drastically declining eastern and Carolina hemlock populations. They formed the Alliance for Saving Threatened Forests (now known as the Forest Restoration Alliance) and work to share information and restore hemlocks and other native adelgid-affected trees in the eastern United States.

Today, modeled after the successful American Chestnut Foundation’s program, our selective breeding facility in western North Carolina works to breed and establish a future of resistant trees in North American Forests. The alliance also works with citizens in their Tiny Terrors, a citizen science project where anyone can upload information about affected and potentially resistant trees, helping researchers to locate resistant trees and track the adelgid’s spread across forests. They also work with genetics labs and hope to find adelgid-resistant trees from clonal stock.

At the FRA, researchers and government organizations can band together to make a difference in North America’s forests. Together, and only together, can we restore our forests so future generations can stand in the shadows of these giants.