After wildfire sweeps through timber, as it does every summer across the American West, the inclination of foresters is to salvage the scorched trees. Turning them into paper and lumber, the reasoning goes, is better than letting them decay. It removes dead wood that could fuel future fires, and it clears the area for seedlings.
New evidence, though, suggests that salvage logging increases the risk of future conflagrations and interferes with forest regeneration by killing most of the seedlings that reemerge on their own.
Researchers at Oregon State University recently examined the aftermath of a massive fire that encompassed nearly 500,000 acres of southern Oregon in 2002, the so-called Biscuit fire. They reported last week that salvage logging there destroyed about 70 percent of seedlings that had sprouted from the forest floor and increased the risk of future fires.
"Not everything leaves on the log truck," said John Campbell, researcher in the university's department of forest science. "We found that the process of logging in this type of situation actually produces a large amount of fine fuels on the ground that, unless removed, could increase fire risk, not decrease it."
Forest policy is a big deal in the West, which is mostly national forest and other public land. Ongoing fires in southern Colorado forcing hundreds of people to evacuate would seem to boost the argument for quick logging in fire-damaged areas. But this new report on negative impacts of salvage logging could hamper the forest product industry's efforts to persuade policymakers to move more aggressively in that direction.
The forestry debate also focuses attention on climate change as a long-term factor in federal forest management - a relatively new development in the long-running dispute over whether to conserve old-growth forests or to treat them as a natural resource to be harvested.
Industry spokesmen say the prospect of global warming argues for salvage logging and replanting before it becomes harder to kick-start new forests that could act as "carbon sinks," trapping the carbon dioxide that constitutes the most troublesome greenhouse gas causing global warming.
"The climate's going to be drier and hotter, and the ability to survive as seed dropping on top of ash versus a [planted] seedling that's got 10 inches of root stuck down into the ground is going to be significantly different," says Chris West, vice president of the American Forest Resource Council, an industry group in Portland, Ore.
Scientists here in the steep mountains of southern Oregon, as well as others reporting recently in Science magazine, say such industrial logging harms the watersheds on which nature relies. They contend, too, that forests generated naturally, as opposed to monocultures grown for paper and lumber, are more resilient to climate change.
"If you're going to roll the dice on climate change, which is what we're doing globally right now, which are you going to want to have?" asks Dominick DellaSala, a forest ecologist who heads the World Wildlife Fund's program in Oregon. "The product of millions of years of genetic processes, the local trees that are coming back naturally on their own, that are more resilient to climate change? Or are you going to want nursery stock grown under very specific conditions to produce fiber?"
Of Oregon State's study of salvage logging three years after the Biscuit fire, Mr. West of the industry group says, "The real research and knowledge will be gained 10, 15, 20 years out." He cites areas logged after fires a decade ago that now show healthy, recovering forests.
It's a classic case of legitimate short-term interests - preventing next year's fires and boosting local economies reliant on natural resources - versus the natural world of plants and animals, water and weather that is just as legitimate but operates on a much longer time scale.
Some scientists point to the natural recovery of what had been labeled "catastrophic" disturbances, such as the eruption of Mount St. Helens in 1980 and the Yellowstone fires of 1988.
"A general lesson has been the great resilience and recuperative capacity that are characteristic of natural forests," Jerry Franklin, professor of ecosystem science at the University of Washington, told a congressional hearing in November.
Bills in the US House and Senate would accelerate the process of approval for postfire salvage logging on federal lands.