In 2007, an estimated there were 178.6 million visits to national forests across the country, down 13 percent from the 204.8 million in 2004, The Oregonian in Portland, Ore., reported. The decline was 27 percent for forests in Washington and Oregon and 24.3 percent in the eastern region, which includes the New England states and some of the Midwest.

Visits to undeveloped forest areas, where the main activities are hiking and backpacking, dropped from 8.8 million in 2004 to 6.3 million in 2007.

"I think that there is cause for concern," Thomas More of Northern Research Station in Vermont said to the newspaper. "There's some important consequences for rural communities and for people's chance to get out and enjoy being in the outdoors."

Don English, head of the service's visitor monitoring program, said that some of the apparent decline may have come from employees learning how to use a new counting program but he said that some of the drop is real, The Oregonian said.