Bay Nature magazineJanuary-March 2012


Deadline Looms for Solano’s Rockville Trails

January 10, 2012

With the clock ticking toward a February deadline, the nonprofit Solano Land Trust is working to purchase 1,500 acres of land known as Rockville Trails in Solano County. Located across the road from Fairfield’s Rockville Park, this property has been slated for estate housing for at least 30 years. For just as many years, the Green Valley Homeowners Association has fought that plan, guided by a vision of turning the property into protected open space. Recently, a lawsuit put a stop to development plans and allowed the land trust to buy 330 acres of the property, with an option to purchase the remaining 1,170 acres for $15.5 million by February 28, 2012. If the land trust can’t raise the money, the current landowner will be allowed to build 185 homes on the site.

All that development pressure seems far away when you are out on this wide-open landscape, especially in the shadow of one of the oracle oaks here.

Oracle oaks are hybrids between interior or coast live oaks and California black oaks, explains oak expert Ted Swiecki of Phytosphere Research. Black oaks have long been coveted for wood products, so it’s not uncommon to find just a few of them among many live oaks. “That sets up a situation where the last remaining black oaks may be inundated with pollen from the other species but with little or none from their own species,” Swiecki says. The result is an oracle oak.

I set out on a wide, dirt ranch road with Pam Muick, coauthor of Oaks of California, to find a group of oracle oaks mapped in one of the environmental documents for the proposed subdivisions. The volcanic soils had absorbed the rain from a previous day’s storm–boding well for trail maintenance and wintertime hiking.

We reached the spot where the oracle oaks were supposed to be and saw a few contenders. We climbed a bit higher and headed north on a steep-sided slope to a beautiful valley once slated for homes. Dramatic clouds floated above soaring turkey vultures and red-tailed hawks. Western bluebirds banked in and out of a large California coffeeberry in the blue oak savannah.

Muick climbed up to a particularly beautiful oak and soon declared it to be an oracle. The leaves were lobed like a black oak, but ovate like a coast live oak. The tree also had a mix of green and yellow leaves, a telling characteristic of an oracle. “If we came back a month from now, we’d see that the tree still had some of its leaves,” she said.

We found a few more oracles in a concentration known as a hybrid swarm. Here, explained Muick, you find specimens with varying degrees of their parents’ and grandparents’ characteristics. On one tree you might find leaves that look like a live oak’s but are as big as those of a black oak. On another, you might see those that look like black oak leaves but have the boat shape of a coast live oak.

Fortunately, the conservation and botanical importance of Rockville Trails has not gone unnoticed by major open space funders; both the Gordon and Betty Moore Foundation and the California Coastal Conservancy’s Bay Area Program have committed funds to the property’s acquisition.

If Rockville Trails is fully protected as an open space, the Bay Area Ridge Trail Council plans to complete six miles of trail that will link the property to Rockville Hills Park, the Vallejo Lakes Watershed, and ultimately the Napa-Solano Ridge Trail, says the Ridge Trail Council’s Janet McBride. For more information, go to

About the Author

Writer Aleta George trained as a Jepson Prairie docent in 2009. In addition to writing Bay Nature's Ear to the Ground column, she has written for Smithsonian, High Country News, and the Los Angeles Times.

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