Colorado Republican Scott McInnis, who chairs a House forestry subcommittee, said green groups have repeatedly gone to court to block attempts by the federal government to thin forests. The delays have led to overgrown brush that becomes tinder in spreading fires such as the ones in Arizona and Colorado.

"The environmental community ... has attempted to walk away from its share of the blame," said McInnis. "I am urging those environmental groups to sit down, come to us with ways to work through this."

McInnis and other lawmakers said green groups such as the Sierra Club had little incentive to work with the U.S. Forest Service to reach an agreement because they can simply delay a project in court.

Thinning a forest removes the overgrowth of underlying brush and dead trees, which serve as fuel in the spread of wildfires, especially during a drought.

Environmental groups and some lawmakers have long opposed efforts to thin forest land, contending the government is too eager to remove large trees coveted by big timber companies for profit. The groups also say commercial logging increases fire risks by leaving flammable debris behind.

The Forest Service is trying "to blur the lines and say any management activity is fuel reduction," said Sean Cosgrove, a forest specialist with the Sierra Club.

Less than one-third of the forest thinning projects proposed this year by the Forest Service are near homes or other buildings, according to green groups.

The green groups argue the Forest Service has not thinned enough land near homes, focusing its attention on removing lumber in areas where the public is not in danger.

"The public and general populous will be more responsive to an agency that says, 'We're doing our best, but we need to do better,' instead of this lets blame anybody and everybody so we don't have to take full responsibility for our actions," said Keith Ashdown, a spokesman with Taxpayers for Common Sense.

The Forest Service, a division of the U.S. Agriculture Department, estimated that as many as 50 percent of all thinning projects are challenged in court.

However, a study by the General Accounting Office, Congress' investigative arm, found less than 2 percent of projects were appealed. The study is now being reviewed by the GAO.

The Forest Service "got caught with their hand in the cookie jar," said Jay Inslee, a Washington Democrat. "They want to do logging for big timber rather than fuel reduction."

About 3.1 million acres (1.26 million hectares) of land already has burned this year across the United States, nearly double the 10-year average, according to the federal government.

Drought conditions throughout much of the Southwest, Rockies and the East coast add to the risk of forest fires this year. The agency said Arizona, Colorado, Wyoming and California have the greatest fire risk during July.

In Arizona, the Chediski fire has consumed about 468,000 acres (190,000 hectares) while wiping out millions of dollars worth of timber sold by Indian tribes for income. The Hayman fire in Colorado, 55 miles (88 km) southwest of Denver, burned 137,768 acres (55,750 hectares) and destroyed 133 homes.