EUGENE, Ore. (UPI) -- The history of western U.S. wildfires suggests current conditions and fire-managements practices could mean a dangerous future for the region, a study says.

Researchers from the University of Oregon and other institutions said the American West has seen a recent increase in large wildfires due to droughts, the buildup of combustible fuel in forests, a spread of fire-prone species and increased tree mortality from insects and heat, all of which could contribute to "a perfect storm" for more fires.

While grazing and fire-suppression policies have managed to keep incidents of wildfires unusually low for most of the last century, the amounts of combustible fuel, temperatures and drought are all rising, a UO release said Wednesday.

"Consequently, a fire deficit now exists and has been growing throughout the 20th century, pushing fire regimes into disequilibrium with climate," the researchers said.

"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," lead author Jennifer R. Marlon at the University of Wisconsin, Madison, said.

Future policies must take into account how strongly climate and people affect the present-day landscapes and forests of the American West, researchers said.

"Policymakers and others need to re-evaluate how we think of the past century to allow us to adjust and prepare for the future," UO researcher Patrick J. Jartlein said. "Recent catastrophic wildfires in the West are indicators of a fire deficit between actual levels of burning and that which we should expect given current and coming climate conditions. Policies of fire suppression that do not account for this unusual environmental situation are unsustainable."

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