New Logging Curbs Imposed for Sierra Nevada : Ecology: The ban on clear-cutting and safeguards for the oldest trees are designed to protect the California spotted owl and extend from the Oregon border to Sequoia National Forest.

In a controversial move, the U.S. Forest Service imposed tough new restrictions Wednesday on logging throughout the Sierra Nevada to protect the California spotted owl.

The restrictions, banning clear-cutting and the logging of the largest and oldest trees from the Oregon border south to Sequoia National Forest, are scheduled to take effect in March. They will apply for at least two years while scientists continue their studies of the owl and its habitat needs.

“We adopted these guidelines because . . . studies indicated that our current management did not reflect the latest scientific thinking on how to adequately protect the species and keep it from becoming listed as threatened with extinction,” said Ronald Stewart, chief of U.S. Forest Service operations in California.

Stewart said the rules were merely an interim measure and that any economic harm would be short term.

Those in the logging business, however, predicted that the decision would cost California up to 15,000 jobs, drive up the cost of lumber and deal a painful blow to the state’s beleaguered timber industry.

“The impacts are going to be extreme,” said Jim Craine, a forester with the California Forestry Assn. “We need to do something to protect wildlife habitat, but this is an overreaction by the Forest Service. We don’t need Draconian measures like these.”

Bill Coates, chairman of the Board of Supervisors in timber-rich Plumas County, said: “It’s a vicious attack on rural communities. We’ve already had a lot of families move out, and we’ve got unemployment between 20% and 30% up here. This is just going to make the human tragedy worse.”

Environmentalists, meanwhile, applauded the Forest Service’s action and expressed hope that it signals a shift in the agency’s management approach.

“In the past, the Forest Service has emphasized clear-cutting and logging of the largest trees. This new approach is exactly the opposite,” said David Edelson, senior attorney at the Natural Resources Defense Council.

Moreover, Edelson said: “There seems to be a shift in philosophy. I think the intent is to change the focus of national forest management from cutting timber to restoring and protecting healthy forest ecosystems.”

The California spotted owl is a subspecies of the northern spotted owl, an endangered species whose status resulted in a court injunction restricting logging in the forests of Northern California and the Pacific Northwest. That injunction has helped send the timber industry into a tailspin, causing mill closures and layoffs.

Eager to avoid a similar legal fight over the California spotted owl, the Forest Service in 1991 asked scientists to study the creature and its habitat needs. They were unable to determine whether California’s spotted owl population was declining but concluded that cutting the old trees favored by the birds would jeopardize it. Based on the findings, Stewart formulated the restrictions announced Wednesday.

Under the new logging policy, all trees with diameters greater than 30 inches will be off limits and logging will be prohibited in a 300-acre zone surrounding each spotted owl nest.

The rules apply to Eldorado, Inyo, Lassen, Modoc, Plumas, Sequoia, Sierra, Stanislaus and Tahoe national forests, encompassing about 5.3 million acres. The Forest Service predicted that the restrictions would result in a 27% decline in the timber harvest, while industry representatives said the reduction would be 50% to 60%.