Sustain Our Nation's Forests and Grasslands

The fight to save eastern hemlock

People standing outside near woods
Partners and volunteers are provided a safety briefing with project details before the hemlock treatments begin---January 29, 2020. USDA Forest Service photo by Kimberly Bonaccorso.

KENTUCKY—When it comes to fighting hemlock woolly adelgid, a non-native pest that’s killing our eastern hemlock trees, it takes teamwork. Fortunately for the Daniel Boone National Forest, plenty of dedicated partners and volunteers are onboard to assist.

During two recent “hemlock treatment days,” approximately 30 volunteers treated more than 1,000 eastern hemlocks, or Tsuga Canadensis, on national forest lands. As volunteers marked and measured each tree for treatment, approved insecticide handlers carefully measured imidacloprid according to the tree’s diameter. The chemical was then poured into the soil at the tree’s base. In the same way that a tree absorbs water from its roots, the insecticide will travel up the tree and spread into its branches and needles where adelgids feed on the sap.

When the insects suck sap from tree branches, they hurt hemlock growth and, without treatment, trees will die within a few years. The bug was initially found in southeastern Kentucky in 2006, and, since then, several hemlock trees have been decimated.

The Daniel Boone National Forest has 92 hemlock conservation areas where hemlock trees are targeted for treatment. In addition to the 92 conservation areas, the forest is currently implementing Phase II of proposed actions. In phase II, an additional 3,000 acres will be treated with chemical control methods.  
The eastern hemlock is one of the longest living tree species in the eastern United States, reaching maturity anywhere from 250 to 300 years. Individual trees may live to be 800 years old. The species is considered an important forest component, especially along streams in the Appalachian forests.

Several organizations are committed to conserving eastern hemlock in Kentucky’s forests, helping coordinate volunteer efforts and other efforts, including Kentucky Heartwood-Hope for Hemlocks of Kentucky, Kentucky Division of Forestry, and Sheltowee Trace Association. 

FS worker helping people measure a tree
Each hemlock tree’s diameter is measured to determine the amount of insecticide required for adequate treatment---January 29, 2020. USDA Forest Service photo by Kimberly Bonaccorso.
FS employee working in the forest
Forester Jacob Royse pours insecticide for soil application at the base of a nearby hemlock tree---January 29, 2020. USDA Forest Service photo by Kimberly Bonaccorso.