The Roadless Area Conservation Rule, which protects 58.5 million acres of virgin US national forests, has been repealed by the Bush administration.
New regulations open up the possibility of road building and logging in the forests, which cover 38 states.
State governors can file petitions to stop road building on some of the 34.3 million acres where it is now permitted or request that new forest management plans be drafted to allow construction on parts of the other 24.2 million acres.
The US agricultural department, which includes the Forest Service, intends to work closely with governors to meet the needs of local communities while protecting the forests.
More than 1.7 million people opposed the Bush plan during Forest Service public consultation last year.