16CDEXTRA1.JPG An undated photograph provided by the nonprofit National Trust for Historic Preservation shows the deteriorating masonry walls of the Chimney Rock pueblo near Pagosa Springs, Colo. A report by the private, nonprofit National Trust for Historic Preservation released on Thursday, May 16, 2008, says that the U.S. Forest Service's lack of a clear mandate to protect historic sites and buildings and its escalating costs for such duties as firefighting are endangering hundreds of thousands of cultural resources such as Chimney Rock pueblo across the country. (AP Photo/HO, National Trust for Historic Preservation)

DENVER (AP) _ Indian pueblos, Revolutionary and Civil War battlefields and trails used by Lewis and Clark are in jeopardy because the Forest Service lacks the means to protect them, a prominent preservation group said Thursday.

The nonprofit National Trust for Historic Preservation released a report saying the U.S. Forest Service lacks a clear legal mandate and the financial ability to protect thousands of historic sites and buildings on national forest lands from development, vandalism and other threats.

Richard Moe, trust president, said in a news conference in Denver that only about 1,900 of 325,000 Forest Service sites identified as historically or culturally significant are on the National Register of Historic Places.

"It's estimated that more than 2 million sites of cultural and historical significance may be out there on Forest Service land," Moe said.

At-risk treasures include American Indian pueblos and sacred sites, petroglyphs, Revolutionary and Civil War battlegrounds, trails used by the Lewis and Clark expedition and Forest Service lookout towers.

About 80 percent of the 193 million acres the agency manages in 44 states and Puerto Rico haven't been surveyed for such sites, according to the Washington, D.C.-based trust.

"The National Forest System: Cultural Resources at Risk" says the Forest Service, unlike other federal land management agencies, has no statute that specifically mandates historic or archaeological preservation as part of its mission.

Other threats are off-road vehicle use, oil and gas development in the West, livestock grazing, logging and a resurgence in uranium, gold and other hard-rock mining, Moe said.

A 2005 report by the group said the federal government's push to develop energy on millions of acres of land overseen by the Bureau of Land Management was leaving natural and cultural resources at peril.

A big issue for the Forest Service is funding. Less than 1 percent of its $4.4 billion budget goes to heritage resource programs, according to the new report.

"The Forest Service is understaffed and underfunded," Moe said.

His group has called for doubling the Forest Service's $14.5 million budget for heritage programs.

Joel Holtrop, deputy chief of the National Forest System, said the agency could do more with more money, but that could mean diverting funds from somewhere else.

"It's likely going to happen at the expense of something else," Holtrop said.

Nearly half of the Forest Service's budget is spent on fires, including fire suppression and decreasing wildfire risk. Forest Service officials have said the increase in the number, frequency and complexity of wildfires because of encroaching development are driving up costs.

Budget constraints are stretching Forest Service staff, Moe said. He noted that Forest Service personnel recently discovered a 10-foot-tall painting of the cartoon character SpongeBob SquarePants on the chimney of a historic cabin in central Colorado's Pike National Forest.

"Vandalism is increasing because there aren't enough forest rangers to protect these places," Moe said.

In Missouri, the trust has placed 70 historic buildings slated for demolition in the Mark Twain National Forest on its most endangered places list. The trust says the forest's master plan gives priority to new construction over preserving historic structures.

The Forest Service is studying how to deal with huge growth in use of the Red River Gorge in Kentucky's Daniel Boone National Forest. Moe said some campers sleep and cook in prehistoric rock shelters in the gorge.

Holtrop and Moe noted the Forest Service's successes, including the restoration of the historic Interlaken Resort in Colorado's San Isabel National Forest. The Forest Service teamed up with the national trust and other nonprofits on the project.

Volunteers and nonprofits are working to protect Chimney Rock Pueblo in the San Juan National Forest in southwest Colorado. Moe said the area's pueblos are the farthest northern points related to New Mexico's famed Chaco Canyon, a center of the ancient Puebloan culture.

Moe said the trust wants to work with the Forest Service to draft legislation that would explicitly state that the agency is responsible for cultural resources on land it manages.

"We have responsibility for managing cultural resources in the national forest system, a responsibility we accept and accept proudly," Holtrop said.

Forest Service leaders, who met with the trust a couple weeks ago to discuss the report, are updating policy to emphasize the importance of preserving and protecting archaeological and historic resources. Holtrop said some of the revisions are responses to the trust's work and others have been in the works.

"The report corroborates some of what we were doing," Holtrop said. Working with groups like the National Trust will help leverage more funds for the agency, he added.