The Santa Anas are kicking up, overturning semis on the interstate miles to the north. I too fear a similar incident amid the live-oak-filled hills that surround Limestone Canyon on the

Irvine Ranch Land Reserve. The high winds already have shattered one tree, and its debris blocks an access road, but at least I’m not on the freeway. I march along on a late November day

with a group heading for ridgelines that frame a striking geologic anomaly locals call the Little Grand Canyon. A guide from the Nature Conservancy, which manages this parcel that abuts

Cleveland National Forest in southeastern Orange County, invited me to walk an 8-mile track on what once was ranchland. Within the next decade, Orange County will assume control of the

reserve is private, but conservancy guides Trish Smith and Mike Kahle accompany some of the 14,000 members of the public who wander through annually. Smith is a sixth-generation Californian,

and Kahle grew up in nearby Irvine. Both are fiercely protective of the reserve and all who roam there — be they clawed, hoofed, shod or scaly. Anyone can arrange to explore the area on

foot, bicycle or horseback. Hikes range from a 2 miler to a 15-mile loop. Bike and horseback rides can be longer, but check with the conservancy before saddling up. Calling Limestone Canyon

a “wilderness area,” as the handout does, is a stretch; at times I’m walking on fire roads wide enough for large utility vehicles. But by all other measures, it’s one of the wildest areas in

Southern California. Silence reigns every time the wind abates, the hills insulating us from urban noise. A pair of golden eagles was recently sighted at the reserve — apparently to put the

hawks and turkey vultures on notice — though no nest has yet been found. Ringtail cats, bobcats and mountain lions prowl the sage and sumac while horned lizards and rattlesnakes wait in

their lairs. I miss seeing the top predator but do spook some band-tailed pigeons on the way to Dripping Springs, a geologic fault that seeps rainwater percolating from the ground. A lush

springtime makes flowers and ferns (and poison oak) burst from every fissure of the springs. The best times to visit, I am told, are from mid-April until June, or after extended rains. The

reserve doubles as a research lab: A graduate student is using smelly lures and bristled carpets to snag hair samples from bobcats to track their number and movements. The conservancy also

traps coyotes and bobcats as part of a wide-ranging study with other agencies, including the National Park Service. Winding up what has become a ridgeline, I turn a corner and find myself

gaping at the Sinks, the Little Grand Canyon. An ancient landslide and flow has left layers of sedimentation in contrasting stages of erosion. River-deposited layers on top are craggy and

resilient; marine layers that fell away maybe 60 million years ago are softer and have eroded and slid down the canyon. Swallows and kites chase each other through gaps in the 100-foot

canyon walls. “We’re five miles as the crow flies from the Irvine Spectrum,” Trish says. “This is the other O.C. nobody knows about.” The particulars Where: Limestone Canyon on the private

Irvine Ranch Land Reserve in Orange County. What: An 8-mile hike with 1,000 feet of gain. Hiking, biking and equestrian tours are led by guides; once a month, Limestone Canyon is open to the

public. Call the Nature Conservancy at (714) 832-7478 or e-mail [email protected]. How: From the 55 Freeway, exit at Chapman Avenue and head east. Chapman turns into Santiago Canyon Road;

continue south to Hicks Canyon gate. ------------------------- _ Do you have a favorite hike close to home that you want to share? Invite us along. E-mail us at [email protected]. _ MORE

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