When storms do damage, our first instinct in the aftermath is to start cleaning up. That logic has been applied to trees knocked down in the forest, too, with the assumption that we can help a damaged stand of trees recover if we clean out uprooted trees and broken limbs. It’s an assumption that appears to be wrong.
A new study published in the journal Ecology and reported on by Todd McLeish in Northern Woodlands (Spring 2013), suggests that the best thing we can do to help a damaged forest recover is simply leave it alone. “When a forest is damaged by hurricane winds, even if it is quite a big disturbance and looks catastrophic, there are a lot of surviving structures that allow the forest to come back and continue functioning,” said Audrey Barker-Plotkin, a site and research coordinator at Harvard Forest, and the lead author of the study.
The study is based on 20 years of research into how a controlled, two-acre sample of mature oak forest rebounded after scientists pulled down 80 percent of the trees, and left the dying trees on the ground. Surprisingly, scientists found that the forest repopulated itself with mostly black birch rather than oak, the soil nutrient level remained unchanged, invasive species had a more difficult time flourishing, and litterfall returned to pre-study levels by year six. In short, the dominant variety may have changed, but the health of the ecosystem was minimally impacted by the dead trees. The study recommends that unless the purpose of the forest is to provide timber (in which case, you should feel free to clear salvagable timber), there’s no need to “help” out a natural process. As David Foster, director of the Harvard Forest, notes, “What appears to us as devastation is actually, to a forest, a quite natural and important state of affairs.”