As any cloth grocery bag–toting San Franciscan knows, there are myriad paths to planetary salvation. None is quite so satisfying, however, as buying land outright. The Nature Conservancy dedicates itself to doing just that, in the form of purchasing conservation easements and prohibiting critter- and plant-destroying development on vital swaths of land in perpetuity. Seven years ago the S.F.–based group bought California's largest conservation easement, about 200 miles north of the city, called Denny Ranch. These 36,000 acres are now off-limits to development. The ranch is part of the conservancy's Lassen Foothills Project, covering 1,300 square miles from the foothills of Lassen Peak west to the Sacramento River. The organization feels that putting aside as much of this land as possible will help preserve habitat for chinook salmon and steelhead trout and safeguard one of the most biologically important regions of California. Of course, visitors are discouraged from climbing over fences and frightening cattle. But a day trip to the multiple campgrounds, parks, and miles of live oaks and grasslands in the western foothills of Mount Lassen might give you an idea of what all the environmental fuss is about. The ranch spans the north and south sides of Highway 36, about seven miles northeast of Red Bluff on the way to Mount Lassen. After driving north 3 1/2 hours from San Francisco on Interstate 5, take the Red Bluff/Antelope Boulevard exit heading toward Chico. Turn left onto Highway 36 and go seven miles. The grass, brush, volcanic boulders, and California blue oaks you see on either side of the highway are destined, by contract, to remain more or less the same forever.