Steven Meister / Mt. Taylor Hotshots via Reuters

Burned terrain in the Gila National Forest, New Mexico, is seen in a photo supplied by the United States Forest Service on May 30. The Whitewater-Baldy Complex fire was the largest fire ever in New Mexico, burning about 300,000 acres.

GRANTS PASS, Ore. -- Big changes are in store for the nation's forests as global warming increases wildfires and insect infestations, and generates more frequent floods and droughts, the U.S. Department of Agriculture warns in a new report.

The study released Tuesday is part of the National Climate Assessment and will serve as a roadmap for managing national forests across the country in coming years.

It says the area burned by wildfires is expected to at least double over the next 25 years, and insect infestations often will affect more land per year than fires.

Dave Cleaves, climate adviser to the chief of the U.S. Forest Service, said climate change has become the primary driver for managing national forests, because it poses a major threat to their ability to store carbon and provide clean water and wildlife habitat.

"One of the big findings of this report is we are in the process of managing multiple risks to the forest," Cleaves said on a conference call on the report. "Climate revs up those stressors and couples them. We have to do a much better job of applying climate smartness ... to how we do forestry."

The federal government has spent about $1 billion a year in recent years combating wildfires. Last year was the warmest on record in the lower 48 states and saw 9.2 million acres burned, the third-highest on record, according to the National Oceanic and Atmospheric Administration website.

Insect infestations widely blamed on warming temperatures have killed tens of millions of acres of trees. 

For years, hikers across the country have had to pay a fee to park at U.S. Forest Service sites and trail heads. A federal court last month called into question parts of the fee structure, but the service on Thursday emphasized that while the program has been under review the fees remain in place -- at least for now.

"Visitors to national forests should continue expect to pay the established recreation fees that are currently in place," the Forest Service said in a statement. "The U.S. Forest Service has charged user fees since 1965 and, since the mid-1990s, more than 90 percent of those fees have been used for improvements to the areas where the fees have been collected."

A federal court last month concluded that parking fees in the Coronado National Forest in Arizona were improper and ordered a lower court to review its ruling. 

The fees are $5 for a daily vehicle pass or $30 for an annual one.

Some hikers have accepted the fees as a way to maintain trails, while others complain that the federal government should fund those services as it had in the past. The debate has gone on for years at online forums like nwhikers.net.

The Forest Service said it is reviewing the court order but that in the meantime would continue to collect fees as well as continue a review that began two years ago.

That review last January led to preliminary proposals whereby "26 national forest areas will still require visitor fees, down from the current 90 areas nationwide," the service stated.

The Los Angeles Times reported that proposed changes include charging for use only at some busy sites that have six specific amenities that require maintenance -- among them toilets, interpretive signs, trash cans and picnic tables.

Service spokesman Larry Chambers told msnbc.com that the proposals would limit fees to a "much smaller area ... essentially just around the specific site where the amenities are offered."

The service said it expects to have a final decision after this fall and that public comment will be sought during that time.

Some $60 million in fees were collected across the national forest system last year. The service says most of the revenues are kept by the forests where they are raised in order to provide maintenance and improvements.

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Siskiyou Project via AP file

National forest uses include logging like this work in Oregon's Siskiyou National Forest. Trying to balance resource use and resource protection has been controversial.

It's no easy task figuring out how to balance forest and wildlife protection with logging, drilling and offroading on the nation's 155 national forests, but the Obama administration on Thursday unveiled a rule it says will do just that. An era of collaboration and less litigation was promised with the rule managing forests, but some initial reaction by interested parties -- which range from environmentalists to loggers to offroaders -- was not promising.

"Our preferred alternative will safeguard our natural resources and provide a roadmap for getting work done on the ground that will restore our forests while providing job opportunities for local communities," U.S. Agriculture Department chief Tom Vilsack vowed in a statement.

The rule essentially revises the existing framework for how each forest's managers must proceed with a given issue -- be it a request to log, a request to protect some species or even a request to open part of a forest to offroad vehicles.

The U.S. Forest Service, which is part of USDA, last year issued a draft of the rule for public review. That process generated more than 300,000 comments that Vilsack said were weighed and, in some cases, incorporated into the final rule. 

Unlike national parks, which protect resources, national forests were created to balance resource protection with resource use but that still hasn't prevented decades of legal battles.

"We expect to see much less litigation because of the increased collaborative effort" in deciding what happens in each forest, Forest Service Chief Tom Tidwell told reporters.

Officials noted that several changes were made to the draft, including adding emphasis on "sound science" and, according to Tidwell, "beefed up protection of water resources."

Tidwell said the rule would also streamline how each national forest is managed, which will free up "more time, more money to get the restoration done" across the 193 million acres of forest.

The Natural Resources Defense Council had a mixed initial take on the rule. "It is much more meaningful about getting local officials to apply the best available science," NRDC forest analyst Niel Lawrence told msnbc.com, and there's "significant improvement in public participation."

But the environmental group is also "very concerned" because the rule removes a provision ensuring that wildlife will have viable populations distributed across the forests where they are now found, Lawrence said. "It jettisons the single most important conservation protection" on U.S. forests over the last 30 years, he added.

The NRDC intends to lobby the administration and if that doesn't work a lawsuit is "perfectly possible," Lawrence said.

A timber industry group, for its part, told msnbc.com that it needed a day or two to review the rule. But, in a statement issued right after the rule, the American Forest Resource Council voiced concern. "We are very concerned about whether the agency took the comments we made on the draft rule to heart and made changes needed to avoid the mistakes of the past," said council President Tom Partin.

The BlueRibbon Coalition, a group representing offroad interests, also said it was still reviewing the rule.

In Congress, the chair of the House Natural Resources Committee, Washington state Republican Doc Hastings, said the concerns he'd raised earlier "fell on deaf ears."

"These new Obama regulations introduce excessive layers of bureaucracy that will cost jobs, hinder proper forest management, increase litigation and add burdensome costs for Americans," he said in a statement.

Last November, Hastings' committee hosted a hearing where critics piled on against the draft rule.

"First, the proposed planning rule will increase the complexity, cost, and time for the Forest Service to complete forest plans," testified Scott Horngren on behalf of the American Forest Resource Council. "Second, of greater concern, is that the planning rule will make the projects that implement the plans more vulnerable to lawsuits than they are today."

The last time the planning rules were updated was in 1982. Several attempts to revise it have been thrown out by federal courts. In 2009, a Bush administration plan was struck down. Environmentalists had fought the rule, saying it rolled back key forest protections.

The Obama administration decided not to challenge that ruling and instead come up with new rules.

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