The mudslides that killed at least five people in Oregon last month have created a controversy in the perennial Pacific Northwest battleground over the logging practices of timber companies.
Mudslides are a relatively common and natural occurrence in this part of the world. But environmentalists warn they will be more frequent and severe because of the clear-cutting of forests on steep slopes.
"This kind of unsafe logging is just plain wrong," says David Bayles of the Pacific Rivers Council in Eugene, Ore.
Timber companies and the public agencies that regulate logging practices respond that the link needs further study. They also say that people who settle in areas near steep terrain that were once uninhabited cause just as big a problem.
"We have a history of landslides in the Pacific Northwest prior to any man's activity," says Chris West, vice president of the Northwest Forestry Association.
State officials note that the house that was buried in the Nov. 16 mudslide was built on an alluvial fan, or the endpoint of an earlier slide. As early as 1986, a state official said the site had a "high potential for slide damage."
But the question environmentalists have raised is whether the clear-cut above the house made the slide more likely to happen.
Clear-cutting and road construction may make a landslide occur as much as five to 20 times more often than on a forested site, says Gordon Grant, a researcher with the US Forest Service in Corvalis, Ore.
After a winter storm in February caused extensive flooding and landslides, environmentalists collected anecdotal evidence that found that 70 percent of the hundreds of landslides originated in areas that had been clear-cut, Mr. Bayles says.
Bayles and leaders of 67 other environmental groups have called for a moratorium on logging on steep slopes.
Timber industry representatives and Oregon Forestry Department officials say that demand is "premature." "We cannot tell landowners they cannot harvest their trees," says Lou Torres, the department's spokesman. "We can only require them to harvest in a certain way."
Meanwhile, the Forestry Department is conducting a study of the February and November winter storms to examine the connection between clear-cuts and landslides. It comes at the confluence of three trends that have roiled the land-management world.
*Timber companies increasingly are harvesting on steep terrain in areas that once were passed up because restrictions limit logging on public lands.
*More people are moving to the Northwest, pushing new development into areas that put people at high risk.
*A climatologist is forecasting that a 20-year drought cycle is coming to an end, and a 10- to 20-year wet cycle is about to begin.