It¿s wildfire season again, when infernos consume verdant forests and lick the edges of communities. The images are now familiar: a low-flying plane sprays a pink cloud of fire suppressant; yellow-jacketed firefighters hike between tall charcoal pillars that were healthy trees just days before. Less well known, perhaps, are the rangeland fires, where a 20-mile-an-hour wind will carry fire across 100,000 acres. "What you see on TV is generally the forest fires," says Mike Pellant, the coordinator of the Great Basin Restoration Initiative. "The rangelands and the deserts are kind of the lands that are forgotten and not thought about by people."

In the arid steppe of the Great Basin, an invasive weed called cheatgrass has turned what was once a vibrant ecosystem into a tinderbox covering an estimated 25 million acres. Bureau of Land Management officials and scientists are exploring ways not only to mitigate the damage caused by wildfires but also to restore the Great Basin to a healthier status. Researchers are only just beginning to understand the complex relationship between fire, invasive weeds and native plants in the region, and it may be years before there is a well-defined plan to heal America¿s big sky country. "There¿s a pretty substantial group now that¿s looking at the big picture, beyond just killing weeds," says Tony Svejcar, a U.S. Department of Agriculture researcher in Oregon. "We really need to look at how these plants compete for resources."

In 1999 more than 2.2 million acres of land burned in the Great Basin (out of the 5.6 million acres of wildland consumed that year), according to Bureau of Land Management statistics. This year, heavy spring rains watered an abundance of cheatgrass, which blankets most rangeland, growing continuously between widely spaced native grasses such as sage. Cheatgrass dries out early in the summer--it was dry by June this year in most areas. Its wheatlike spiny seed pods make excellent kindling, easily ignitable by lightning, a cigarette butt or even the hot wheel rims of a car stopped by the side of the road. Because of that fine texture, "it burns really fast," explains John Szymoniak of the National Interagency Fire Center. "It¿s the same principle as starting a fire; you don¿t start a fire with a log."

Cheatgrass hegemony has become something of an ecological disaster for the Great Basin [see "Other Offenders" for information on additional weed invaders]. For ranchers who depend on wide expanses of open land for grazing, losing several thousand acres in a fast-burning range fire denies them use of that land not only for the rest of the year but also for up to three years after that, while the plants regrow. If the area is then dominated by cheatgrass, this provides food only for the brief few weeks that the weed is still green.

Furthermore, cheatgrass sprouts from new seeds every year. Although rainy seasons like this past spring can lead to bumper crops of cheatgrass, during a drought hardly anything grows at all, leaving ranchers with acres of bare land. "Production can be zero in a dry year," Pellant says. "In a wet year it can be as tall as a barbed-wire fence."

Before the invasion of cheatgrass in the late 19th century (it was brought in from central Asia), native grasses grew in clumps spaced one or two feet apart. Fires would advance slowly, having to always jump from plant to plant. Because the native plants stayed green until late summer, wildfires were more difficult to ignite, and an area would burn once every 40 to 100 years.

Cheatgrass, however, grows close together, leaving virtually no space between plants. Winds gusting 20 or 30 miles an hour on the plains can carry the front of a fire just as fast, forcing firefighters to literally race to keep up with the flames. In addition, dry cheatgrass throughout the summer means there is a greater chance of a fire starting. What used to be a 40-year fire cycle has shrunk to a five-year cycle. "I¿m standing out here now and the cheatgrass is already dry while the native grass is still green," Pellant reports, calling from Idaho on his cell phone. "This burned five years ago, and if there was a fire here now it would burn right through."

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