Site: Harvard Forest LTER

The hemlock forest, as seen from the Woods Road to the tower.
Credit: David R. Foster- Harvard Forest Archives

Three decades of research on abrupt declines in pre-European hemlock populations, long term regional measurements of hemlock decline from the invasive insect hemlock woolly adelgid, and the long term Hemlock Removal Experiment confirm that hemlocks are a foundation species. They control forest structure, composition, and microclimate, with cascading trophic effects extending from mammals to microbes. As invasive insects proliferate across North America, HFR LTER is developing a generalizable understanding of population, community, and ecosystem level responses.