Eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana) are threatened by several non-native pests and pathogens. The Nature Conservancy (TNC), in partnership with USFS, is undertaking a three-year “Trees in Peril” project with public agencies, research institutions, and nonprofit partners to advance tree breeding programs and genetic research for five of the most imperiled tree species in the Northeast, including eastern and Carolina hemlock.
Identifying hemlock trees that remain healthy despite long-term exposure to hemlock woolly adelgid (Adelges tsugae) (HWA) and elongate hemlock scale (Fiorinia externa) (EHS) is a necessary step for advancing hemlock breeding programs. TNC and the New York State Hemlock Initiative at Cornell University (NYSHI) convened a working group in late 2022 to develop protocols for identifying and reporting lingering hemlock trees.
The working group developed two draft protocols: one to record lingering hemlock tree candidates in areas that have experienced high hemlock mortality (Lingering Hemlock Tree Search Protocol), and one to monitor conditions in areas where there is not-yet-significant HWA- or EHS-induced mortality (Hemlock Health Monitoring Plot Protocol). The draft protocols were shared with a variety of hemlock resistance stakeholders at a meeting organized by the Holden Arboretum on April 18.
The working group is accepting feedback on the hemlock protocols through May 31! Visit this website to view/download the protocols and complete the short Feedback Form. The working group will be testing the protocols it has developed this spring and summer with the hope that they will be useful in identifying lingering hemlock in the years ahead.
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