VALLEY CENTER —— Representatives of the historical Rancho Guejito are preparing to send a development application to the county, possibly as early as April, according to a timeline submitted to county planners.

The vast 22,000-acre property east of Escondido —— the last undivided Mexican land grant in California —— was once proposed as a state park and is now used to raise cattle.

The ranch is owned by the Rodney Co., a New York-based real estate firm whose owner, Philadelphia shipping magnate Benjamin Coates, died last year at 86. Earlier this year, land-use consultant Jim Whalen of J. Whalen Associates in San Diego submitted a multiyear schedule for environmental studies and a map of potential development areas on 7,300 acres of the ranch, county records show.

Any move toward large-scale development of the property will face protest, environmental advocates say. A recent report from the Conservation Biology Institute, an environmental think tank in Encinitas, calls Rancho Guejito "the conservation jewel of San Diego County" with miles of pristine forest and grassland and extensive archaeological resources.

"This is a national park-quality landscape," said David Hogan at the Center for Biological Diversity, an environmental legal group.

He described the report as a call to arms among local environmentalists. "Now, it's just a matter of time until people organize around preserving it," he said.

No details

The development proposals do not include concrete information such as the number, sizes or types of buildings that could be proposed for Rancho Guejito. How much building could be allowed remains undecided, county planners said last week.

Whalen referred questions about the property to Henry Rupp, a Murrieta lawyer who represents the Rodney Co. Rupp said last week that the studies do not indicate impending development, but rather the company's interest in studying the ranch's habitat.

"We have successfully protected that property for decades," he said. "We're simply gathering information on its biodiversity, as part of our stewardship."

Conservation jewel

Rancho Guejito's 22,000 acres stretch from the San Pasqual Valley north almost to the La Jolla Indian Reservation. It is bounded on the east by the Cleveland National Forest and on the west by Valley Center.

Cattle graze on the southern, flatter part of the property at an elevation of about 1,500 feet, while a rugged forested area at the north end contains a 4,221-foot peak, Pine Mountain.

Mostly grassland and chaparral, Rancho Guejito has 15 percent of the county's increasingly rare Engelmann oak woodland, the largest remaining block, according to the Conservation Biology Institute report. Studies in the early 1990s found that 16 species of raptors, such as golden eagles, make their home on the ranch, the reports states.

The ranch also shelters over 80 prehistoric American Indian sites, including ceremonial art, pottery, hearths, figurines and human remains, the report says.

County records show only one recent survey in 2004 for an endangered species, the Stephen's kangaroo rat. In addition to the confirmed presence of thousands of kangaroo rats, habitat models outlined in the report also suggest the presence of the endangered arroyo toad and the least Bell's vireo.

The report was compiled from publicly available data without the cooperation of the property owners, said its principal author, Jerre Stallcup, who helped design a conservation plan for San Diego County in the 1990s.

"We wanted to get the facts out there so that decision-makers can see how valuable it is," she said.

Ranch was almost a park

In 1974, the state parks division recommended acquiring Rancho Guejito as a park and nature reserve, but the purchase was vetoed by incoming Gov. Jerry Brown.

Originally, Rancho Guejito, then 13,299 acres, was given in 1845 by Mexican governor Pio Pico to rancher Jose Maria Orozco, Valley Center historian Petei McHenry said.

Charles Powell, a Los Angeles engineer, bought the ranch in 1939 and raised cattle there until his death in 1959.

Benjamin Coates purchased the ranch from Powell's estate in 1974 for $10 million —— after the sale to the California parks department fell through —— and placed the property in the name of the Rodney Co. in 1988.

Coates died on Dec. 7, 2004, in Haverford, Pa., according to an obituary in the Princeton Alumni Weekly. He served as a naval intelligence officer during World War II and ventured into the oil tanker business after the war. He is survived by his wife, two children and two grandchildren, according to the obituary.

The current ownership of the Rodney Co. is not clear. It is registered in the Netherlands Antilles, according to the London-based firm International Company Profile.

Conservation plans constrain building

Although the timeline submitted to the county in May projects a development application for Rancho Guejito in April 2006 and Board of Supervisors approval in 2011, that schedule could be delayed.

Two ongoing planning processes will largely determine when and how Rancho Guejito could be developed. The first, the county's updated General Plan 2020, scheduled for completion in 2007, will determine its zoning.

The ranch is now zoned agricultural, with one home allowed per 40 acres, said Ivan Holler, the county's deputy director of planning and land use.

Keeping with the county's "smart growth" policy of restricting backcountry building, county planning officials in 2003 recommended zoning it at one home per 160 acres. An alternative map proposed by the county Board of Supervisors in 2005 keeps it at one home per 40 acres.

Rupp said last week that the county's proposals to "downzone" the ranch reduce the value of the Rodney Co.'s property as borrowing collateral, even if no building is planned.

"It's not a just reward for our stewardship," he said.

Where building could occur is regulated under the county's Multiple Species Conservation Program, a bargain between developers and environmentalists seeking to preserve valuable habitat in some areas in return for streamlined building permits elsewhere. A draft of the North County part of the plan is scheduled for release in mid-2006.

County planners have been using the rule of thumb that high-quality habitat such as Rancho Guejito should be 75 percent preserved, said Tom Oberbauer, the conservation program's director.

According to county planners, consultant Whalen has been wrangling with them over how the Guejito property will fit into the conservation program.

Whalen earlier wanted to draw boundaries outlining precisely where development could occur, but state and federal wildlife agencies asked for more environmental studies of the land, Oberbauer said.

More recently, Whalen proposed that Rancho Guejito be removed from the North County conservation plan, and a separate plan created just for the ranch property, Oberbauer said.

"We haven't figured out what that would mean yet," he said.

Not for sale

Environmental advocates say that the Guejito property is prone to fire and not easily accessible by road, and thus inappropriate for development. The property lies east of the San Diego County Water Authority's service limit, so any future homes would rely on wells unless a pipeline is built.

"The infrastructure costs would be so huge," said Dan Silver, of the Endangered Habitats League. "The public good is not to build luxury houses that taxpayers would have to subsidize."

Silver suggested that the county could acquire the land with some of the money that is expected to be raised from a countywide TransNet half-cent sales tax.

Rancho Guejito is several times larger than any San Diego County property recently pursued by leading conservation organizations, even with the help of state grants.

Rupp said that the Rodney Co. is not interested in selling, and suggested that Rancho Guejito's acquisition by the government as a park might result in more environmental impact than if it remains a working ranch.

"The government's obligation is to the public," he said. "Our obligation is to the property."

Contact staff writer Quinn Eastman at (760) 740-5412 or qeastman@nctimes.com.