In blown down forests, a story of survival

Contact: Clarisse Hart, Harvard Forest Outreach Manager
Telephone: (978) 756-6157 (9a to 5p)
Email: hart3@fas.harvard.edu

October 16, 2012

PETERSHAM, MASSACHUSETTS—In newscasts following intense wind and ice storms, damaged trees stand out: snapped limbs, uprooted trunks, sometimes entire forests blown nearly flat. In the storm’s wake, landowners, municipalities, and state agencies are faced with important financial and environmental decisions. A study by Harvard Forest researchers, supported by the Long-Term Ecological Research Program and soon to be published in the journal Ecology, yields a surprising result: when it comes to the health of forests, native plants, and wildlife, the best management decision may be to do nothing.

Salvage logging is a common response to modern storm events in large woodlands. Acres of downed, leaning, and broken trees are cut and hauled away. Landowners and towns financially recoup with a sale of the damaged timber. But in a salvaged woodland landscape, the forest’s original growth and biodiversity, on which many animals and ecological processes depend, is stripped away. A thickly growing, early-successional forest made up of a few light-loving tree species develops in its place.

But what happens when wind-thrown forests are left to their own devices? The Ecology paper reports results of a 20-year study at the Harvard Forest in Central Massachusetts. In 1990, a team of scientists recreated a major hurricane in a 2-acre patch of mature oak forest. Eighty percent of the trees were flattened with a large winch and cable. Half the trees died within three years, and the scientists left the dead and damaged wood on the ground. In the twenty years since, they’ve monitored everything from soil chemistry to the density of leaves on the trees. What they’ve found is a remarkable story of recovery.

Initially, the Harvard site was a nearly impassable jumble of downed trees. But surviving, sprouting trees, along with many new seedlings of black birch and red maple – species original to the forest – thrived amidst the dead wood. Although weedy invasive plants initially tried to colonize the area, few persisted for long.

According to David Foster, Director of the Harvard Forest and co-author of the new study, “Leaving a damaged forest intact means the original conditions recover more readily. Forests have been recovering from natural processes like windstorms, fire, and ice for millions of years. What appears to us as devastation is actually, to a forest, a quite natural and important state of affairs.”

Following severe tornadoes in Massachusetts in June 2011, the Commonwealth of Massachusetts’ Division of Fisheries and Wildlife pursued this controversial watch-and-wait policy at a site in Southbridge, Massachusetts. There, salvage work will be limited to providing access routes for public safety. Division of Fisheries & Wildlife Forestry Project Leader John Scanlon reports, “As a wildlife agency, we made the decision not to salvage the tornado impact area because we saw tremendous potential wildlife habitat benefits. We were impressed at how quickly the impact area was occupied by lush, native vegetation. It supports everything from invertebrates to salamanders, and black bears love to winter in thick brush piles and forage for insects in rotting logs.”

While a range of economic, public safety, and aesthetic reasons compel landowners to salvage storm-damaged trees, study co-author Audrey Barker-Plotkin suggests that improving forest health should not be one of them. “Although a blown-down forest appears chaotic, it is functioning as a forest and doesn’t need us to clean it up.”

The Harvard Forest, founded in 1907 and located in Petersham, is Harvard University's outdoor laboratory and classroom for ecology and conservation, and a Long-Term Ecological Research (LTER) site funded by the National Science Foundation. Its 3,500 acre property is one of the oldest and most intensively studied research forests in the U.S. Open to the public year-round, the site includes educational and research facilities, a museum, and recreational trails. More information can be found at http://harvardforest.fas.harvard.edu/.

The Long-Term Ecological Research (LTER) program was created in 1980 by the National Science Foundation to conduct research on ecological issues that can last decades and span huge geographical areas. The network brings together a multi-disciplinary group of more than 2,000 scientists and graduate students. The 26 LTER sites encompass diverse ecosystems in the continental United States, Alaska, Antarctica, and islands in the Caribbean and the Pacific—including deserts, estuaries, lakes, oceans, coral reefs, prairies, forests, alpine and Arctic tundra, urban areas, and production agriculture.

To download images to accompany this story, please visit http://harvardforest.fas.harvard.edu/press-resources-1016-hurricane-story

For additional information, or for an interview with the quoted scientists and land managers, please contact Clarisse Hart at 978/756-6157 (9a-5p) or email hart3@fas.harvard.edu.

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