Los Osos Valley farmer Don Warden has signed a historic conservation easement on his Highland Ranch, a deal that is already serving as an example for others interested in keeping their farmland in agriculture for future generations.

In a deal valued at more than $1.7 million late last year, Warden sold almost all the development rights on the 535-acre Highland Ranch to the Land Conservancy of San Luis Obispo County.

“This is the first of its kind in the area,” said Stacey Smith, conservation project manager with the Land Conservancy. “It’s definitely caught the attention of quite a few farmers.”

The deal is unique because its primary goal is to preserve the land as a working farm. Other land conservation deals have had wildlife habitat preservation or open space protection as their main goals, Smith said.

The ranch is on Los Osos Valley Road about halfway between San Luis Obispo and Los Osos. It stretches from the road south to a wooded ridgeline in the eastern foothills of the Irish Hills.

The Highland Ranch is typical of many farms in the county in that it’s a diversified operation. The lower elevations near the road are used to grow a variety of vegetables.

The upper elevations are used as grazing land for a herd of cattle. The upper elevations also contain oak woodlands, making them valuable habitat for such wildlife as deer and bobcat.

The ranch also has serpentine soils in spots, which support rare plant communities that are unique to the San Luis Obispo area. Protecting these habitats is a secondary goal of the easement.

The agreement allows Warden to build two homes on the property, but overall development is limited to 2 percent of the acreage. Warden is free to manage the property as he sees fit as long as it stays a productive farm.

“The farm has been in the family for 145 years,” Warden said. “It’s good to know it will stay in agriculture.”

There are practical benefits to the conservation easement over and above the satisfaction that the land will stay in agriculture in perpetuity. The money from the easement as well as the stability it gives the farm’s future has aided the family in its estate planning, Warden said.

Word of the conservation deal has gotten out and has piqued the curiosity of other farmers in the area. Smith said she gets three or four calls a week from other farmers who are interested in similar deals for their land.

Conservation of the ranch is something of a change of heart for Warden. In 2000, he helped lead the fight to stop the SOAR initiative, which would have required a vote of the people to rezone land in the county for more intense uses.

About five years later, Warden tried to subdivide the ranch to create an 18-home clustered development. The expense and difficulty of pushing that project through the county planning process prompted Warden to drop those plans and look for other options.

Groups and agencies that contributed money for the easement are the National Guard and Camp San Luis Obispo, the California Farmland Conservancy Program, the Morro Bay National Estuary Program, the Harold J. Miossi Charitable Trust and the Chevron Community Grant program.