WASHINGTON (AP) -- The U.S. Forest Service is marking its 100th anniversary amid debate over whether it is living up to the mission President Theodore Roosevelt gave it in 1905: to "perpetuate the forest as a permanent resource of the nation."

In contrast to the revelry expected for a January 3-6 centennial celebration, some say the Forest Service is so tied up in litigation that it no longer has the sharp focus provided by legendary forester Gifford Pinchot, its first director.

"A hundred years later the whole picture is significantly more complex," said Dale Bosworth, the Forest Service's chief. "The population has increased significantly. There are much more demands than there were 100 years ago in terms of recreation and solitude."

From overgrown forests that contribute to major fires to the spread of invasive species and urban encroachment on open space, the agency's 37,000 employees have a host of modern concerns, Bosworth said.

In December the Bush administration released rules for the national forests that some environmentalists complain relax ecology-friendly restrictions and make it easier to log vast swaths of public lands.

Former Forest Service Chief Jack Ward Thomas said Roosevelt and Pinchot would hardly recognize the agency they created.

"I think they would be distressed with the current state of affairs -- the confusion and the lack of a clear mission," Thomas said. "I think they'd despise that."

Chris West, vice president of the American Forest Resource Council, a timber industry group, said relentless lawsuits are obstructing the agency's efforts.

"The public didn't entrust the courts with the management of these lands. They entrusted the Forest Service," West said.

Environmentalists concede that lawsuits have increased, but they accuse the Bush administration of flouting long-established law in an effort to boost logging and gas and oil development. Courts are often the only way to protect the environment, they say.

The Forest Service "is rapidly reverting to industry-biased policies from decades past that made logging and drilling the highest priorities," said Steve Holmer of the United Forest Defense Campaign, a coalition of environmental groups.

Holmer and others cite the administration's efforts to transfer control of remote, roadless forests to governors as well as the December 22 announcement of forest rules that give regional managers more discretion to approve logging and other commercial projects without lengthy environmental reviews.

Forest Service officials say the new rules will allow managers to respond more quickly to changing conditions, including wildfires, and emerging threats such as invasive species.

Andy Stahl, executive director of Forest Service Employees for Environmental Ethics, a watchdog group, called next week's Centennial Congress an exercise in self-congratulation.

"I think it makes a lot of sense to celebrate the national forests. I think it makes no sense to celebrate the Forest Service management of the national forests," Stahl said.