Remote Pine Flat Road northeast of Healdsburg once carried visitors to a 19th century boom-and-bust mining town, traces of which have all but disappeared.
In more recent decades, it's been the site of deer poaching, target shooting and even the occasional dumping of a human body from a crime committed elsewhere.
But things are different these days.
On a recent tour of a green, hilly preserve about four miles up the road from Alexander Valley, biologist Sherry Adams spoke of the transformation taking place.
"Our strategy is changing how it feels to come up Pine Flat Road," she said. "It was a Wild West mentality."
As more land in the area has come under some form of conservation protection, the deer poaching around Pine Flat has pretty much stopped, she said.
The area now is defined by 12,000 acres of contiguously protected properties that are wildlife and plant havens.
But the most isolated and private parcel is the 1,750-acre Modini-Ingalls Ecological Preserve, just acquired by Audubon Canyon Ranch, for which Adams works.
"It's a natural treasure," Adams said of the land, home to deer, black bears, mountain lions, coyotes, fox, otters, turtles and nesting golden eagles.
The property belonged to the late Jim and Shirley Modini, the couple who bequeathed the former sheep and cattle ranch to Audubon Canyon Ranch.
It had been in Jim Modini's family since 1852, when his aunt and uncle, Theresa and Timothy Ingalls, were homesteaders there.
The Modinis, who began living on the property in the mid-1940s, were known for their love of the land and animals.
After initially placing a "forever wild" easement on it in exchange for $1 million from the Sonoma County Agricultural Preservation and Open Space District, they deeded the property to the environmental organization.
The transfer became final in late December, five months after the widowed Shirley Modini died.
Now it's the setting for scientific studies and habitat restoration projects, some of them funded by an endowment of more than $1 million that the Modinis attached to their gift.
"It's a great laboratory," said Scott Feierabend, executive director of Audubon Canyon Ranch.
The land rises from 400 feet above sea level to the 2,700-foot peaks of Ingalls bluff. It has lofty views of Mount Saint Helena, Knights and Alexander valleys and encompasses three creek systems that flow into the Russian River.
The 2004 Geysers Fire ravaged the area and destroyed a barn on the Modini property. Although there still are blackened trunks of pine, oak and Douglas fir, many saplings regenerated from the ashes.
"It's a remarkable story of how nature heals itself," Feierabend said.
On a tour Thursday, Adams pointed out some of the pines with cones that do not open to spill their seeds without fire. And she noted the serpentine outcrops with harsh soils in which rare plants can grow.