Invasive grass blamed in Western wildfires

UNIVERSITY PARK, Pa., Dec. 5 (UPI) -- An invasive grass species may be one reason fires are bigger and more frequent in certain regions of the Western United States, a team of researchers says.

Scientists at Penn State say cheatgrass, a plant species accidentally introduced by settlers in the West during the 1800s, was involved in a disproportionately high number of fires in the Great Basin, a 230,000-square-mile arid area that includes large sections of Nevada and parts of Utah, Colorado, Idaho, California and Oregon.

"Over the past decade, cheatgrass fueled the majority of the largest fires, influencing 39 of the largest 50 fires," Penn State researcher Jennifer Balch said. "That's much higher than what it should be when you consider how much of the Great Basin that cheatgrass covers."

While cheatgrass grasslands make up only about 6 percent of the Great Basin, the average size of the fires in those regions was significantly larger than fires in areas dominated by other vegetation including pinyon-juniper areas, montane shrubland and agricultural land, the researchers said.

"From 2000 to 2009, cheatgrass burned twice as much as any other vegetation," Balch said.

The ability of cheatgrass to rapidly spread and fill in ground between other plant species may be one reason the plant is involved in larger and more frequent blazes, she said.

"What's happening is that cheatgrass is creating a novel grass-fire cycle that makes future fires more likely. Fire promotes cheatgrass and cheatgrass promotes fires."