The Bush administration has set aside Reagan-era rules aimed at protecting wildlife in national forests, rules that environmentalists had used to block logging projects in the Pacific Northwest and elsewhere.

Under a temporary regulation published last week, U.S. Forest Service managers reviewing road-building, logging or other proposals are allowed to waive the 22-year-old requirement that the forests maintain "viable populations" of fish and wildlife. Instead of having to conduct population counts of representative species, for example, officials now can rely on "best available science," a less specific standard, to guide their decisions.

The change, which is not subject to public comment, is the latest move in an ongoing battle over how to protect vulnerable species in national forests. The forests cover 191 million acres, or roughly 8 percent of the national landscape, and are home to one-quarter of the U.S. species at risk of extinction.

In the last year of the Clinton administration, officials issued stricter regulations requiring forest managers to maintain conditions that provide a "high likelihood" of maintaining the viability of native and desired plants and animals. The Bush administration suspended the Clinton rules in May 2001, and the Forest Service has been drafting a replacement regulation since then. In the meantime, forest managers have been relying on the 1982 standards.

The regulation issued last week declared that "the 1982 rule is not in effect" but gave managers the option of applying the older standard voluntarily when revising forest-management plans.

Forest Service spokesman Dan Jiron initially said in an interview that there was "zero difference" between the new rules and what the administration had put in place in 2001, but he later said evaluations of specific projects will now be conducted differently.

Environmentalists and some academics blasted the switch, saying it would undermine protections for animals including moose and the Appalachian brook trout.

"For the first time since 1982, the government is saying we no longer have any legal obligation to maintain wildlife populations on national forests," said Mike Leahy, natural resources counsel for Defenders of Wildlife.

Timber industry officials, however, said they do not believe the move would ease restrictions on logging. Christopher West, who represents makers of forest products in 12 western states as vice president of the American Forest Resource Council, said that the new distinction "to us is meaningless" and that "people are crying wolf for election-year politics."

Jiron also dismissed the criticism as unfounded, saying the administration will use other scientific methods to assess how animals are faring. He said managers will focus on gauging habitat conditions "to ensure you have a dense habitat for wildlife."

Environmental groups have repeatedly charged that the administration was not conducting adequate population counts of "indicator species," which give a sense of how other plants and animals are doing in the forest. In June, for example, the U.S. Court of Appeals for the 10th Circuit in Denver ruled that federal officials did not do a sufficient population count of several Utah forest species; the new rule may bolster the administration's case that such surveys are not critical.

The rule issued last week noted that courts have required population counts for years but asserted that "other tools often can be useful and more appropriate in predicting the effects of implementing a land management plan, such as examining the effect of proposed activities on the habitat of specific species."

But Leahy at Defenders of Wildlife questioned this approach, noting that in Wyoming's Teton Mountains the Forest Service has accelerated the issuance of permits allowing helicopters to fly skiers to mountaintops. He said the flights may not harm habitat but they disturb wolverines in the area.

The rules issued last week went into effect immediately without a public comment period, Jiron said, because "it's an interpretation of an existing rule."

Contractor Sam Bickle goes to work last year in Olympic National Forest. Environmentalists expect more timber sales without the wildlife rules.