BOISE, Idaho — The Bush administration Monday proposed lifting a national rule that closed remote areas of national forests to logging, instead saying states should decide whether to keep a ban on road building in those areas.

Environmentalists immediately criticized the change as the biggest timber industry giveaway in history.

Under the proposal, governors would have to petition the federal government to block road-building in remote areas of national forests. Allowing roads to be built would open the areas to logging.

The rule replaces one adopted by the Clinton administration and still under challenge in federal court. It covers about 58 million of the 191 million acres of national forest nationwide.

The Bush administration heralded the plan as an end to the legal uncertainty overshadowing tens of millions of acres of America’s backcountry.

“Our actions today advance the Bush administration’s commitment to cooperative conserving roadless areas,” Agriculture Secretary Ann Veneman said in announcing the plan in the Idaho Capitol Rotunda.

Philip Clapp, president of the National Environmental Trust, called the administration proposal the biggest giveaway to the timber industry in history, arguing that many western states would likely press for development to help struggling rural economies.

“The idea that many governors would want to jump headfirst into the political snake pit of managing the national forests in their states is laughable,” he said. “Besides, the timber industry has invested heavily for years in the campaigns of governors with the largest national and state forests, giving almost equally to Republicans and Democrats.”

Under the proposal, the 58.5 million acres designated as roadless among the 191 million acres of national forest will be protected from development for another 18 months.

In 2006, each governor may submit a proposal either to continue protecting the roadless land or allow it opened to multiple use. The federal government would consider each state petition and then issue a regulation determining the extent of future roadless protection.

Idaho has the most land in the lower 48 states affected by the roadless designation — 9.3 million acres — and was one of the first states to challenge the Clinton administration rule.

A major point of contention in Idaho could be 200,000 acres in the Clearwater River area of north-central Idaho. The area is untrammeled, and conservationists want it preserved. But the Forest Service has proposed some timber sales in the area, and land managers believe logging would reduce the danger of wildfire and protect the basin’s famed elk herd.

Veneman and Idaho Gov. Dirk Kemptorne, a Republican, both argued that the proposal ends the legal uncertainty over the old rule and leaves forest management decisions with people most aware of local needs.

But New Mexico Gov. Bill Richardson, a Democrat and Clinton administration energy secretary, accused the Forest Service of “walking away from environmental protection.”

Richardson said he would petition for protection of all 1.1 million roadless acres in his state and urge other governors to do the same, declaring that “they should not open these areas, period.”