Groups representing people who enjoy using recreational vehicles in the nation's public parks and forests are "falling out of love" with their former allies, the environmental lobby, says an official of a recreational umbrella group.

Having successfully restricted mining, logging, grazing and hunting on public lands under the Clinton administration, environmentalists have now set their sights on restricting use of recreational vehicles such as snowmobiles, personal watercraft, motorcycles, all-terrain vehicles and four-wheel-drive vehicles on public lands.

That agenda is driving recreational groups into the arms of natural resources groups.

• More than 100 environmental groups yesterday petitioned the federal government to restrict motorized vehicles on public lands because they are "shattering the quiet and harming both the wildlife and landscape of America's cherished public lands."

• The Blue Ribbon Coalition, which embraces about 700 off-road recreation organizations, counters that the goal should be to "preserve our natural resources for the public, not from the public."

• Critics also say the restrictions would lead to the creation of de facto, controversial wilderness designations that would also eliminate all recreational use -- including mountain biking and rock climbing.

• The environmentalists, led by the Wilderness Society, want the Forest Service to develop a national plan to regulate the vehicles.

But while the Forest Service has limited authority to restrict access to public lands, a Forest Service spokesman says supervisors in each forest are deliberately empowered to control day-to-day activities. That's because they are on the scene and know what the needs of the local population are "better than anyone."