County approval of the proposed French Ranch subdivision may have divided San Geronimo Valley residents, but it will result in the largest donation to the Marin Open Space District in its history.

The pending dedication of the French Ranch ridge to the county Open Space district this winter continues a 20-year tradition of lobbying, agitating, and deal-making by San Geronimo Valley residents to preserve their community's natural beauty.

Because of the changing political and legal climate, however, it is likely to be the last Valley property the district acquires for the foreseeable future.

State courts have ruled that government can no longer require developers to donate property to open space, as happened when Marin County approved the Skye Ranch subdivision in Bates Canyon.

And voters are no longer willing to finance costly acquisitions like the $2.1 million purchase of the Gary Giacomini Open Space Preserve.

"This is perhaps our last great hurrah," said Brent Harris, a Lagunitas hiker and trails enthusiast. "Any open space from here on out is going to have to be bought with hard-earned money."

The French Ranch dedication indeed comes at a cost - the construction of 32 new houses.

But the donation of at least 460 acres makes it the largest in county history. And it comes at a time when gifts are the only way the district can acquire new property.

Developer Bruce Burman said the dedication was the result of "intense discussion and compromise" with community representatives. The original development plan called for a private preserve solely for the use of French Ranch homeowners.

One of the Valley negotiators, Richard Gray, said in an interview that assuring public access to that land was a priority if development couldn't be stopped.

"What we had to do was convince [Burman] it's in his best interest to do that," Gray said. "We offered him our goodwill and support...a revolutionary concept in a community opposed to development."

That type of horse trading with developers is not unprecedented, however. The county received 33 acres for the Maurice Thorner Open Space Preserve in 1982 after the San Geronimo Planning Group accepted that an extra house could built on adjacent property.

Although the developer got more houses, the public was assured continued access to property that the community had taken for granted as its own, said Supervisor Steve Kinsey, a San Geronimo resident.

Kinsey said similar efforts are going to be necessary to keep land open to the public.

"We need to use every creative technique to get private open space turned into public open space," he said. "Access for future generations is the greatest gift we can leave."

But the Open Space District's planning and acquisition manager, Ron Miska, said the county cannot be relied upon to acquire open space for the public anymore.

Since the defeat last November of Measure A, which would have provided a quarter-cent sales tax to buy open space and parkland, the district has stopped shopping for new property, he said.

San Geronimo resident Michael Howe, a member of the Parks, Open Space and Cultural Commission, added it is getting more difficult for the county to pay for maintaining the open space it already owns. He said maintaining open space costs the county $75 per acre each year.

"We're faced with an issue of not having money to manage that land," he said. "Every budget cycle we're reminded of that."

When county supervisors approved the Skye Ranch subdivision, they had the authority to require property be set aside for public use, Miska said.

Subsequent court decisions have effectively stripped government of that ability by requiring them to demonstrate why land dedications are necessary for the public good.

"Those were the halcyon days," Miska said, recalling that one condition for county approval of Skye Ranch subdivision was creation of the 370-acre Hendricks/Horne preserves above Woodacre's Bates Canyon and in Lagunitas.

When the Skye Ranch developers offered the entire south ridge of the San Geronimo Valley to the county, the Hendricks/Horne preserves were absorbed into the 1,297-acre Gary Giacomini Open Space Preserve. That sale was a once-in-a-lifetime opportunity, Miska said.

The purchase price was $2.1 million, of which half came from Open Space District reserves and the other half from the Buck Trust.

"It's safe to say there's not going to be anything the scope of Gary Giacomini [Preserve] again," he said. "The era of purchasing giant properties for open space is over, at least for the time being."

But the defeat of Measure A does not necessarily mean county residents won't pay to acquire open space, said Jean Berensmeier of Lagunitas, who sat on the Open Space commission for nearly 20 years.

Berensmeier noted that in the eastern corridor of Marin, residents have asked to form community service areas with the county to share the cost of preserving small parcels of open space.

Most of the delicate land endangered by development is actually in East Marin, Berensmeier said. Except for a few parcels near Mount Barnabe and west of Loma Alta, the Valley landscape is well protected, she said.

Kinsey said future efforts to preserve unprotected land might involve the county's buying development rights. Harris, the trails enthusiast, suggested the Open Space District assure public access on private lands by buying trail easements instead of entire properties.

Whatever efforts the future brings, Miska said, Valley activists have been incredibly effective at preserving any available open space. "They've been persistent, and they've been passionate," he added. "That's what it takes."

That passion and commitment comes from a deep reverence of natural beauty, which is simply part of living in the Valley, explained Berensmeier. "It's part of who we are," she said. "It's organic. We're flesh, blood, and open space."