BEND - Although some of this summer's fires in the forests of Oregon and other western states burned within the natural range of fire intensity, many burned hotter and spread faster than the historic norm. Fire ecologists and other forest scientists teamed up Oct. 23 at a conference in Bend to explore why fire intensity has increased, what effects these uncharacteristically severe fires have on forest resources and other values, and what should be done to make Oregon's forests more fire resilient.
"Nearly a million acres burned at various degrees of intensity in Oregon this year," said Stephen Fitzgerald, an associate professor with the Oregon State University Forestry Extension Program. "The Biscuit Fire alone, the largest in Oregon in more than a century, burned more than 500,000 acres."
Fitzgerald is the lead author and editor of an OSU science paper presented at the conference. The event was based on the OSU report, which summarizes current scientific literature and what is known about fire ecology.
"It is clear to fire ecologists that the aggressive suppression of fire in western forests over the last 100 years - combined with the removal of large fire-resistant trees and inadequate thinning - has contributed to an overload of fuel that is causing fires to be unnaturally hot and severe," Fitzgerald said. "Today more than 80 percent of Oregon's forests are at a moderate to high risk of severe wildfires that are outside the historic norm."
Fitzgerald reviewed fuel and restoration treatments to reduce wildfire severity in the state's forests.
"Three factors determine how a fire burns - weather, topography and fuel," he said, "and the only one of these we can influence is fuel. Reducing the amount of both live and dead fuels is the key to making our forests more fire resilient.
"Thinning is the logical first step," he said. "It not only reduces the fuel load that carries fires into the crowns of trees, it also decreases tree density and thus the potential for fire to spread across the crowns."
He said that follow-up options include more thinning as well as pruning, mowing and prescribed burning, depending on site characteristics, costs, risk factors and landowner management objectives.
While not all forests need treatment, those that do - particularly in the ponderosa pine and dry mixed conifer forests of central, eastern and southwestern Oregon - need it soon to reduce the loss of important values that cannot be replaced quickly. Fitzgerald said it will take a decade or longer before a real impact can be made on the fuel buildup problem and many more decades before success can be declared. A major challenge is the need to apply treatment across a very broad landscape, using historical fire regimes as a management template.
"Treating 100 acres here and there will not significantly reduce the threat," Fitzgerald said. "Hundreds of thousands of acres in large Oregon watersheds will require fuel reduction to modify wildfire intensity."
The Oregon Forest Resources Institute commissioned the OSU science paper and sponsored the fire conference in partnership with the OSU College of Forestry and the Oregon Department of Forestry. Other conference speakers included Jack Ward Thomas, a professor of wildlife conservation at the University of Montana and former chief of the U.S. Forest Service; Hal Salwasser, dean of the OSU College of Forestry; Jim Brown, Oregon State Forester and head of the Oregon Department of Forestry; Colin Hardy, a research forester at the Fire Sciences Laboratory in Missoula, Mont.; Janet Anderson-Tyler, assistant director of Fire and Aviation Management, Forest Service in Washington, D.C., and U.S. Congressman Greg Walden of Oregon's Second District.
The Oregon Forest Resources Institute was created by the Oregon Legislature in 1991 to improve public understanding of the state's forests.