Surviving eastern hemlocks have a story to tell

Will the majestic eastern hemlock be wiped out by an invasive cousin of the aphid? The hemlock woolly adelgid, a native of Asia, was first found on eastern hemlocks in Richmond, Virginia, in the early 1950s and has since killed 95 percent of trees in the East. In the absence of hemlocks, deciduous trees take over, changing the forest ecosystem.

A research team found some surprising results by using tree-ring records to reconstruct how eastern hemlock growth had been altered by the infestation and examining its influence at the cellular level. “The differences in response are not simply a result of differences in infestation levels,” said Associate Professor Carolyn Copenheaver.

“Because cold winter temperatures are simultaneously harmful to hemlock woolly adelgid and beneficial to eastern hemlock trees, unusually cold winters may be doubly beneficial to hemlock survival,” explained Research Associate David Walker. Added Copenheaver, “We anticipate that the results of this study will eventually be used to better predict how eastern hemlock will adapt and change its ecological role in the forest after infestation.” The research by Copenheaver, Walker, and Professor Audrey Zink-Sharp appeared in the Annals of Forest Service.

Read the full press release.