Synthesis of Hemlock Removal Experiment at Harvard Forest 2003-2019

In 2023, we synthesized the data from 6 Harvard Forest Hemlock Removal Experiment datasets (HF054, HF106, HF107, HF125, HF126 and HF161) to discern differences between the girdling and logging treatments from 2004-2019. Forest insect outbreaks cause large changes in ecosystem structure, composition, and function. Humans often respond to insect outbreaks by conducting salvage logging, which can amplify the immediate effects, but it is unclear whether logging will result in lasting differences in forest structure and dynamics when compared with forests affected only by insect outbreak. We used 15 years of data from an experimental removal of Tsuga canadensis (L.) Carr. (Eastern hemlock), a foundation tree species within eastern North American forests, and contrasted the rate, magnitude, and persistence of response trajectories between girdling (emulating mortality from insect outbreak) and timber harvest treatments.