As the state's growing population continues to devour open space, the California state park system increasingly is fighting efforts to build railways, roads, utility lines and commercial ventures that threaten its scenic preserves and historical sites.
Land set aside for the "health, inspiration and education" of the people of California is also coveted by transportation agencies, local governments, utilities and other interests that view parks as the path of least resistance for their projects.
"The target is right on our backs," said Dick Troy, a 30-year veteran of the state Department of Parks and Recreation and former deputy director of operations. "We need to be diligent and remind the public what parks are for."
In the past, state officials have managed to fend off serious threats, including a luxury resort at scenic Crystal Cove State Park in Orange County and highways through the redwoods of Northern California.
But proposed incursions on parkland recently have multiplied, raising fears that these oases soon could be degraded by noise, dust, destruction of wildlife habitat, erosion and water pollution, among other threats.
California's development and business interests contend that parkland should not be off-limits to civic projects if the environment is protected and there are no reasonable alternatives.
"We understand that parks serve a recreational purpose, but they should not preclude other uses, such as gas lines and highways, where appropriate," said Jeanne Cain of the state Chamber of Commerce.
Under current law, parks can be used for such purposes, but the state must declare the property no longer necessary for conservation, and the Legislature must agree.
Perhaps the best-known conflict between preservation and development is unfolding at San Onofre State Beach, a popular park in north San Diego County with 2,100 acres containing scenic wild lands, endangered species, Native American archeological sites, and world-famous surf spots. A toll road agency in Irvine considers it an ideal spot for a six-lane highway.
This week, the state attorney general and environmentalists sued to halt the project.
San Onofre is not the only example. A new study by the California State Parks Foundation, an advocacy group, identified about 115 threats to 73 state parks -- more than a fourth of all such properties. The number is significantly higher than two earlier foundation studies found.
Among the proposals:
* In the 170-acre Candlestick Point State Recreation Area -- the first urban park created by the state -- San Francisco's redevelopment agency might build a major street.
* In the Antelope Valley California Poppy Reserve, home to hundreds of acres dotted with the state's official flower, a proposed raceway and a wind farm with 400-foot turbines threaten to disrupt the tranquillity and panoramic views. Both would be built next to the reserve.
* At Chino Hills State Park, near Corona, there are plans for an expressway, rail projects, two major utility lines, a river project and housing tracts.
* To the south, in Anza-Borrego Desert State Park, one of the largest desert preserves in the nation, San Diego Gas & Electric Co. wants to build a massive transmission line with steel towers up to 160 feet high.
* On the Mexican border, federal officials are proposing a security barrier that would intrude 150 feet into Border Field State Park, which adjoins the fragile Tijuana River estuary research reserve.
Parkland is attractive for civic projects because it is often cheaper than developed land and acquiring it doesn't rile property owners.
The proposed San Onofre route, intended to relieve congestion on Interstate 5, is attractive precisely because it does not require the costly condemnation of several hundred homes and businesses in San Clemente.
The $915-million Foothill South tollway would slice through the northern portion of the park, passing over a largely unspoiled estuary.
The project -- like others around the state -- is not a sure thing. It faces the wrath of conservationists and recreation enthusiasts, and it requires state as well as federal approval because it would use leased Navy land.
"San Onofre is a unique and beautiful place," said Geoff Rizzie, 30, of Anaheim, who regularly camps there. "It's a disgrace that someone would want to turn it into asphalt and concrete."
Critics fear the project opens the door to more of the same. "This is our poster child for the moment," said Elizabeth Goldstein, director of the parks foundation.
The California park system is the oldest and largest in the nation, with 278 properties and 77.2 million visitors last year. It was created in 1864 when Congress designated what is now Yosemite National Park a state park, declaring that its public use "shall be inalienable for all time."
But with California growing by about 560,000 people a year, open space is dwindling, and parks, to some, are losing their sacred standing.