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.2023年，我们整合了6组哈佛森林（Harvard Forest）铁杉移除实验（Hemlock Removal Experiment）数据集（HF054、HF106、HF107、HF125、HF126及HF161），旨在辨析2004至2019年间环割（girdling）与伐木（logging）两种处理方式的差异。森林昆虫暴发会对生态系统的结构、组成与功能造成显著扰动。人类通常会通过实施打捞式采伐（salvage logging）应对昆虫暴发，该举措可能放大短期影响，但目前尚不明确：与仅受昆虫暴发影响的森林相比，伐木是否会导致森林结构与动态特征出现持久性差异。本研究依托一项针对北美东部森林建群树种（foundation tree species）加拿大铁杉（Tsuga canadensis (L.) Carr.，俗称东部铁杉（Eastern hemlock））的移除实验，获取了15年的观测数据，并对比了环割（模拟昆虫暴发引发的树木死亡）与木材采伐两种处理下，森林响应轨迹（response trajectories）的速率、强度与持久性。