As the saying goes, there is no free lunch. But residents now can enjoy a free place for a picnic lunch in the mountains, as the U.S. Forest Service is eliminating fees for 90 percent of the land in Southern California's national forests.

For nearly a decade, visitors to the Cleveland, San Bernardino, Angeles and Los Padres forests have been required to carry an "adventure pass" with them whenever they park at lakes, trail heads and even scenic overlooks along mountain highways. It was all part of a federal experiment to raise more money for forests during an era of declining funding.

"They've done away with the old rec-fee demo program," Judy Behrens, a spokeswoman for the Forest Service in Corona, said Wednesday.

In its place is a new permanent system that authorizes the service to continue charging visitors, but only at popular recreation areas that attract lots of visitors and require a high degree of maintenance, service officials said. Remote and seldom-used areas, as of this week, no longer require visitors to display passes in their windshields.

"I really think that this is going to be an excellent program," Behrens said. "It's going to make it easier for the public, as far as paying fees is concerned. And it will still provide funds for us to maintain our campgrounds and restrooms, and to keep our trails up."

The new program, which affects national forest lands throughout Riverside and San Diego counties, is a result of the passage of a new federal law dubbed the Recreation Enhancement Act.

Because fees will be collected for use on only a tenth of forest lands, service officials expect a significant drop in revenue, but say it is too early to predict how much. Since 1997, adventure-pass revenues for the four Southern California forests have totaled $22 million.

"The high-use areas were where a lot of the passes were purchased, anyway," said Joan Wynn, a service spokeswoman at the Cleveland forest's headquarters in San Diego.

Where fees are still required, there is no change in how much visitors pay, at least for now.

"The fees will still be the same and it'll still be called the adventure pass," Wynn said. "The cost is $5 for a day or $30 for a year."

Passes are sold at service offices and selected stores around the region.

In Riverside County, forest visitors still will need a pass at recreation sites along the Ortega Highway (Highway 74), at Tenaja Trail and Tenaja Falls near Murrieta, at the Wildomar Off-Highway Vehicle Park, and at Humber Park and other popular recreation areas around Idyllwild.

In San Diego County, passes are still required at the Henshaw Wildlife Viewing Area, Observatory and Fry Creek campgrounds, Inaja Memorial and San Luis Rey picnic areas and Orosco Ridge Shooting Area, all in North San Diego County. Fees also are needed at Palomar Mountain Interpretive Station and Mount Laguna.

For a complete list of covered sites, go online at www.fs.fed.us/r5/sanbernardino/ap/rec-fee-sites.shtml and click on "fee areas."

Wynn said the Forest Service is offering pro-rated refunds for those who obtained annual passes recently and don't need them because they visit areas where fees are not charged. Officials urge residents to contact local forest district offices to determine whether fees are required for the areas they are planning to visit.

District offices can be reached at (951) 736-1811 for Western Riverside County and at (760) 788-0250 for northern San Diego County. The main Cleveland National Forest office is (858) 673-6180.

Contact staff writer Dave Downey at (951) 676-4315, Ext. 2616, or ddowney@californian.com.