Irvine Co. Opens Door on 17,000-Acre Reserve : Wilderness: The public gets its first peek at a pristine network of rugged canyons, cliffs and ancient trees.

LIMESTONE CANYON —  Deep in this secluded canyon, time is measured in centuries, even millennia. And why not? Little has changed in the 4 million years since a stream began carving an eternal path through these sandstone cliffs.

Yet, for more than 100 years, few people have stepped foot into this secluded, ancient place called Limestone Canyon. Until now, its visitors, almost exclusively, have been limited to the descendants of rancher James Irvine and their successors at the Irvine Co., headed by Chairman Donald L. Bren.

On Tuesday morning, Orange County’s wealthiest developer donned scuffed brown suede boots and blue jeans to share the canyon with the public for the first time.

“This is a special day,” Bren said before embarking on a two-hour tour led by Nature Conservancy docents. “This is the first time in the 129-year history of the ranch that we’ve opened up land, for the people of cities, for the people of urban areas. For everyone.”

Starting on Saturday, weekly guided tours will be held in this lush, rugged terrain, located off Santiago Canyon Road, east of Orange and Tustin. It marks the public’s first access to the Irvine Co. Open Space Reserve, a network of 17,000 acres owned by the Irvine Co. but bequeathed to the county as future parkland.

This weekend’s inaugural hiking, biking and equestrian tours of Limestone Canyon are the culmination of three years’ work by the Irvine Co. and the Nature Conservancy, an international environmental group known for managing and restoring rare ecosystems.

Nearly five years ago, Bren got the idea to open the land to the public as soon as possible, rather than wait up to 20 years for it to pass into government hands. The land gradually will be turned over in exchange for Irvine Co. development rights on adjacent lands.

“Look around,” said Cameron Barrows, the Nature Conservancy’s Southern California area manager, as he stood next to a wooded stream in Limestone Canyon, “because this is what Orange County and Southern California used to be. There are no other areas that will be protected like this.”

The Irvine Co. Open Space Reserve, generally split into a northern and a southern section, includes wilderness areas in and around Orange, Laguna Beach, Newport Beach, Irvine and Anaheim.

The northern reserve is a diverse, rugged landscape of centuries-old trees, streams and sandstone formations. The southern reserve rings Crystal Cove State Park in the coastal hills between Newport Beach and Laguna Beach.

Two new county parks, on land formerly owned by the Irvine Co., also opened in the past month--Peters Canyon in the Tustin area and Laguna Coast Wilderness Park.

Environmentalists say the Irvine Co. is giving them a rare opportunity to restore entire ecosystems that have nearly disappeared from Southern California.

Still, years of work remain to reverse the ecological damage done by a century of cattle ranching. The Nature Conservancy hopes to gradually return the lands as much as possible to their natural state, making them even richer homes for a diversity of wildlife from mountain lions to rare lizards.

“This is a unique and far-sighted goal that the Irvine Co. has,” Barrows said. “If other landowners can do that, we can perhaps deal better with our environment and endangered species issues.”

The public has not been allowed inside Limestone Canyon since the day that settlers claimed this land. For more than 100 years, only ranchers and some Irvine Co. guests were allowed, although many trespassers over the years couldn’t resist climbing a fence to enjoy the solitude.

About 1 1/2 years ago, the Irvine Co. removed most of the cattle, since cows tend to chew up native grasses, bring in weeds and unwanted foreign grasses, and to erode stream banks.

“The company has been involved with this land for about 125 years, running cattle and some sheep,” Bren said, “and because of that, the land hasn’t been open to the public. People don’t mix with a commercial cattle operations. But as we de-emphasize cattle . . . we can now open some of this land to the public.”

On breezy, sunny Tuesday morning, Bren walked for 45 minutes through Limestone Canyon with about a dozen guests. He especially relished the docents’ tales about the history of the area, which was populated by Gabrielino Indians and early ranchers who lost 75% of their cattle to grizzlies.

“These canyons, on a daily basis, rang with confrontations between man and beast,” Bill Walton, a Silverado Canyon resident who is one of the Nature Conservancy’s volunteer docents, told the group.

Bren said he has frequently visited areas of the new reserves on his own for both business and pleasure, especially Shady Canyon, near the Irvine Co.’s Fashion Island headquarters.

“It’s always a pleasure to get out on the land,” Bren said. “The land is something I’m always a student of. It is important to me both professionally and personally.”

Limestone Canyon is just a mile or two away from the red-tiled roofs of the Irvine Co.’s Tustin Ranch and other nearby developments, yet it is worlds apart. Its pale, gnarled sycamores have stood untouched for two or three centuries. A stream has carved a huge bowl-like sandstone formation, called the Sinks, out of the buff and red-colored sandstone for millions of years.

The oaks and sycamores that grow along streams gradually give way to the arid sage and buckwheat of coastal sage scrub, and then the thick, waist-high native grasses.

Once traversed by grizzly bears and wolves--species long extinct in California--Limestone Canyon still provides homes to mountain lions, bobcats, coyotes, rattlesnakes, hawks, owls and other wildlife.

Bren’s decision to open the land to the public follows in the tradition of James Irvine, who more than 100 years ago dedicated Orange County’s first park, Irvine Regional Park. His goal is to retain the natural terrain for wildlife while still allowing the public to enjoy parts of it.

“Cattle can abuse the land,” Bren said, “but so can people, so what we’ve brought here is a balance.”

For the next few Saturdays, tours will be available only in Limestone Canyon. But within a few weeks, they will be expanded to Emerald Canyon, an ocean-view ridgeline between Crystal Cove State park and Laguna Beach. Reservations, which are required, can be made by calling (714) 832-7478 between 3 p.m. and 5 p.m. Monday through Friday.

Space is still available on four two-hour hikes in Limestone Canyon this Saturday, although that day’s equestrian and mountain bike tours are already full.

Much of the land will remain off-limits because the Nature Conservancy plans to restore large parts, particularly coastal sage scrub, the mix of shrubs used by the gnatcatcher. The bird was declared a threatened species by the Interior Department in March.

Because restoration is “more art than science,” Barrows said, the work will be done gradually over many years.

“We need to think about hundreds of acres at a time,” Barrows said. “Next year, we’ll probably start experimenting, but large scale restoration may be two or three years off.”

Much of the early work, said Nature Conservancy project manager Trish Smith, will be “passive restoration.”

Now that the cattle have been removed, some of the foreign grasses are dying out, and “we can let the land restore itself,” she said. Mowing and weeding can remove others, while still other lands will have to be replanted.

The Irvine Co. has promised to pay for beginning phases, but large-scale restoration work, which can cost millions of dollars, has not been guaranteed. Much of that is contingent on whether the Irvine Co. obtains rights to future development in nearby areas.

More Open Space

Public access to a portion of the new Irvine Co. Open Space Reserve begins Saturday, with guided tours of Limestone Canyon, including the Sinks and Drippings Springs. Emerald Canyon in the southern reserve will open for guided weekend tours in a few weeks. A total of 17,000 acres of land with lush natural resources and scenic landscapes have been set aside by the Irvine Co. as permanent reserves.

Particulars

What: Guided tours of Limestone Canyon

When: Every Saturday

How much: Free

Who: Led by volunteer docents trained by the Nature Conservancy

How: By reservation only

For whom: Weekly hikes, starting out at about two hours, are limited to groups of 20. Separate guided mountain bike tours for up to 20 riders twice per month; guided equestrian tours for up to 10 riders on a request basis.

Information and reservations: (714) 832-7478, 3 to 5 p.m. Monday through Friday. Reservations should be made two weeks in advance. Tour lengths, itineraries and locations will change based on weather and fire conditions, visitors’ skill levels and impact on natural habitat.

Limestone Canyon

Opens Saturday: Home to some of Orange County’s richest oak and sycamore woodlands. Has a unique, 250-foot-deep sandstone formation called “The Sinks,” a mini-grand canyon carved by a stream for millions of years.

Emerald Canyon

Green rolling hills and canyons are mostly coastal sage scrub, the mix of sagebrush and other shrubs that are home to the California gnatcatcher. Ridgelines have sweeping views of the Pacific Ocean.

Sources: The Irvine Co., the Nature Conservancy