Bush administration efforts to speed logging and fire-prevention projects in national forests was set back by a federal appeals court ruling whose most immediate impact could be to halt road building in some Idaho roadless areas and planned timber sales in southeastern Alaska.

The court ruling Thursday means the administration must allow a road and logging ban to take effect that is a pivotal part of former President Clinton's environmental legacy. The Clinton-era rule prohibits virtually all road building or other development in roadless parcels of 5,000 acres or more, acreage that covers a third of America's national forests or 2 percent of the nation's land mass.

A three-judge panel of the San Francisco-based 9th U.S. Circuit Court of Appeals reversed U.S. District Judge Edward J. Lodge of Idaho's temporary injunction that had blocked the rule and sent the case back to Lodge for further consideration.

Environmentalists cheered the ruling, while logging interests and an Indian tribe recoiled.

"The court has just blunted one of the major thrusts of the Bush administration's three-pronged assault on the national forests,'' said Roger Schlickeisen, president of Defenders of Wildlife. "Hopefully, that will cause them to think again.''

On Wednesday, the White House unveiled a new fire-prevention plan that it hopes will allow for quicker cutting of trees and overgrowth on public lands by limiting environmental reviews and public appeals.

Two weeks ago, the administration proposed putting less emphasis on wildlife preservation and other environmental concerns when deciding how much logging or recreation to allow among 192 million acres of national forests and grasslands.

And in May 2001, Bush administration officials said they would let the Clinton rule take effect. But less than a week later, they declined to appeal when Lodge stopped the rule in response to a lawsuit filed by the state of Idaho, the Kootenai Indian tribe of Idaho and logging interests.

Mark Rey, an Agriculture Department undersecretary, acknowledged the ban upheld by the appeals court affecting 58.5 million acres now will go into effect but said government lawyers were reviewing the decision.

He said the U.S. Forest Service "is committed to protecting and managing roadless values'' and places importance on roadless areas already inventoried in the national forest system.

Forest Service spokeswoman Heidi Valetkevitch said the administration was now "working toward developing a rule that would stand up in court.'' Timber and mining interests, as well as some recreational vehicle users, have lobbied the Bush administration to revise the rule.

Two of the few places where the rule's impact might be felt soon were Idaho and Alaska's 17 million-acre Tongass National Forest, where the Forest Service has at least a couple dozen pending timber sales.

With 9 million acres of roadless areas, the Tongass is the largest single region without roads in the nation. But the pending sales depend on a Forest Service re-evaluation of wilderness areas, government officials say. Most new timber sales in remote areas there were temporarily halted this year until the agency finishes work on a court-ordered environmental impact study.

Idaho Attorney General Al Lance said the state would ask the court to rehear the case since the rule could lead to "the spread of unnaturally severe wildfires, insect infestations and forest disease from the national forests to adjacent land.''

The rule will be a blow to the Kootenai tribe's efforts to build roads "to have access to religiously significant sites in the national forests,'' said Raymond Ludwiszewski, the tribe's lawyer.

The vast majority of roadless federal forests are in the West, but smaller sections are scattered across the country from Florida's Apalachicola and Virginia's George Washington to New Hampshire's White Mountains.

Chris West, vice president of timber-industry group American Forest Resource Council, said the Clinton administration never made it clear which areas would be affected.

"The evidence is clear the public did not have the information to thoroughly comment on this proposal,'' West said. "We look forward to Judge Lodge proceeding with this case on the merits.''

The Idaho case is one of about a half-dozen challenges of the roadless rule that had been held up by the 9th Circuit. Now, these cases will likely move forward.

Ruling 2-1, the appeals court said the tribe, the logging industry and snowmobile groups were not irreparably harmed by the rules.

"Unlike the resource destruction that attends development, and that is bound to have permanent repercussions, restrictions on forest development and human intervention can be removed if later proved to be more harmful than helpful,'' Judge Ronald M. Gould wrote.

Judge Andrew M. Kleinfeld dissented, saying the roadless rule increases fire dangers by making remote areas less accessible and should be blocked.

The case is Kootenai Tribe v. Veneman, 01-35472.