Grants Pass, Ore., USA — Logging dead trees after a wildfire and plantingnew ones can make future fires worse, at least for a decade or two while theyoung trees create a volatile source of fuel, scientists found in a study thatcontradicts conventional practices.
The findings by scientists from the U.S. Forest Service and Oregon StateUniversity and published in this week’s Proceedings of the National Academy ofSciences journal raise questions about the long-standing practice of salvagelogging on national forests.
The study, the first of its kind, comes at a time when global warming isexpected to increase the size and numbers of wildfires and the annual cost offighting them is running around $1 billion.
Scientists examined satellite images, aerial photographs and records oflogging and replanting to look at areas that burned in a 1987 fire insouthwestern Oregon and again in a 2002 fire.
The 2002 fire, the largest in the nation that year, has been a battlegroundbetween environmentalists and the Bush administration over harvesting treesafter fire. Only 5 percent of the area burned was logged afterward.
“It was the conventional wisdom that salvage logging and planting couldreduce the risk of high-severity fires,” said Jonathan R. Thompson, adoctoral candidate at Oregon State and the study’s lead author. “Our datasuggest otherwise.”
The large stands of closely packed young trees created by replanting are amuch more volatile source of fuel for decades to come than the large dead treesthat are cut down and hauled away in salvage logging operations, the authorsfound.
“This isn’t the full story,” added Thomas Spies, a researchforester with the U.S. Forest Service Pacific Northwest Research Station, whotook part in the study. “The story could change if you look at a differentplace at a different time,” particularly after young trees have grownlarger and been thinned.
Agriculture Undersecretary Mark Rey, who oversees the Forest Service, notedthat every decision on whether to salvage logs is specific to the wildfire siteand based on a combination of economic and ecological factors.
He added that the study’s findings indicated that on national forests thatburn frequently, it would be a good idea to plant young trees farther apart andkeep the lower branches pruned to reduce fire danger – something the ForestService is starting to do.
Greg Aplet, staff scientist for The Wilderness Society, said a recent reviewof scientific evidence showed that economics – the value of the timber loggedand the jobs that go along with it – is the only real benefit of salvage logging.
“There is no fuel reduction benefit. There is no ecological benefit tosalvage logging,” he said from Denver.
Recent studies suggest that as the climate warms and drought persists acrossthe West, wildfires will become more common. Even the most severely burnedforests will sprout plentiful seedlings on their own.