EUGENE, Ore. -- The American West has seen a recent increase in large wildfires due to droughts, the build-up of combustible fuel, or biomass, in forests, a spread of fire-prone species and increased tree mortality from insects and heat.
In a paper appearing online Feb. 14 in the Proceedings of the National Academy of Sciences, a 12-member research team warns that these conditions may be "a perfect storm" for more fires.
While grazing and fire suppression have kept incidents of wildfires unusually low for most of the last century, the amounts of combustible biomass, temperatures and drought are all rising. "Consequently, a fire deficit now exists and has been growing throughout the 20th century, pushing fire regimes into disequilibrium with climate," the team concludes.
"The last two centuries have seen dramatic changes in wildfire across the American West, with a peak in wildfires in the 1800s giving way to much less burning over the past 100 years," said lead author Jennifer R. Marlon, now a National Science Foundation Earth Science Postdoctoral Fellow at the University of Wisconsin, Madison. "The decline was mostly caused by the influx of explorers and settlers and by their subsequent suppression of wildfires, both intentionally and accidentally."
Marlon earned her doctorate at the University of Oregon, where she studied with co-authors Patrick J. Bartlein and Daniel G. Gavin, professors of geography, as well as with former UO professor Cathy Whitlock, professor of earth sciences at Montana State University. Five other co-authors also hold doctoral degrees from the UO but are now affiliated with other institutions.
Wildfires have been debated for years as either a destructive force of nature that should be eradicated or natural disturbance that keep ecosystems healthy. For nearly 100 years, national policy, as administered by the U.S. Forest Service, had been to respond rapidly to suppress all wildfires, bu
|Contact: Jim Barlow|
University of Oregon