For decades Arizona tumbleweed has been an annoying, worthless desert-dweller that sweeps across the wind-swept landscape, wreaking havoc on farmers as it crushes tender plants, clogs drainage ditches and piles up along fences.

But if researchers at the University of Arizona in Tucson have their way, the pernicious plant may get a new lease on life as a convient fuel source for the southwestern United States and an economic boon as a crop to desert agricultural economies.

Farewell, tumbleweed. Hello, tumblelogs.

With the help of a grant from the Department of Energy and the Arizona Solar Energy Commission, campus researchers have been studying for the last 18 months the large-scale harvesting, cultivation and processing of tumbleweed, which once was best known only for blowing in front of autos on the interstate and, in cowboy movies, for rolling down Main Street during shootouts.

Now it may emerge as the newest desert cash crop.The researchers are turning the pesky plant into slow-burning, high-energy tumblelogs.

"The ones we've produced typically burn two to three hours in the fireplace, and they remain hot throughout the night," said Martin Karpiscak, a research associate in the university's Office of Arid Lands. He said the pulverized logs have outburned mesquite, oak and compacted sawdust products.

"It couldn't supply the vast energy needs of the state," Karpiscak said. "But the general consensus has been that in the future we won't be dependent on any one thing to meet our energy needs but will use a variety of fuel sources. So anything that can make a contribution as an energy source will be of value."

While many farmers would prefer to kill off the annoying weed, which first came to Arizona from Europe in contaminated seed, Karpiscak said researchers are studying new cultivation techniques to foster its growth. "We envision this as a natural crop using existing technology," he said. "We are taking this introduced weed and making it into a viable crop."