SACRAMENTO — The U.S. Forest Service will delay approval of new proposals to harvest living trees in the Sierra Nevada until federal biologists can review the effect of logging on the California spotted owl, officials said Tuesday.

The new policy is designed to minimize harm from logging to the habitat of the owl--a species that is not designated as threatened but is closely related to the endangered northern spotted owl that inhabits forests in coastal Northern California and the Pacific Northwest. As a result of a directive from the Forest Service's regional office in San Francisco, new logging plans will be held up during the next year and a half as federal foresters assess the owl's habitat and the effect of continued harvests.

"What we're doing is taking more of an ecosystems approach," said Matt Mathes, a Forest Service spokesman. "Some future sales of green trees may be delayed. Some may not be allowed. Some may be allowed completely."

The Forest Service and environmentalists want to avoid the kind of controversy that has surrounded federal efforts to protect the northern spotted owl.

The listing of the northern variety of owl as an endangered species has jeopardized the harvest of millions of acres of forests in Northern California, Oregon and Washington. The timber industry has protested loudly that restrictions on logging to save the owl are unnecessary and threaten thousands of jobs.

In its new policy for the California owl, the Forest Service is seeking to steer logging companies into salvaging millions of trees that have died over the last several years as a result of insect infestations, disease and drought in the Sierra Nevada range. Dead trees that remain standing as long as two to three years after they have died can be turned into marketable lumber.

With its new policy, Mathes said, the Forest Service also is attempting to reduce clear-cutting by the private companies that are permitted to harvest trees in public forests.

"The Forest Service is still going to cut trees," he said. "We always will. What we're trying to do is do it in as an environmentally sound manner as we can."

Timber companies that have already been authorized to harvest living trees in the Sierra will not be affected by the change in policy even if logging has not yet begun, Mathes said.

The Forest Service directive covers logging within 8 million acres of National Forests in the Sierra Nevada, a range that extends 400 miles from Mt. Lassen to south of Sequoia National Park.