Petrified Forest Professional Guide
Detailed Trail Description from our Guidebook
"The Petrified Forest is a massive forest of stone trees in the hills of eastern Sonoma County near Calistoga. Sitting at an elevation of 1,000 feet, the fossilized redwood forest resulted from volcanic ash blanketing the area 3.4 million years ago. The buried trees were saturated with water containing silica. The silica seeped into the decomposing wood fibers, slowly replacing the organic material cell by cell. It eventually led to their petrifaction, resulting in one of the best Pliocene fossil forests in the world. The trees all point in a southwest direction, but researchers cannot agree on the origin of the magma blast. In the 1870s, Charlie Evans, a friend of Jack London and Robert Louis Stevenson, discovered the geological wonder while tending his cows. He became known as Petrified Charlie. Uplift, erosion, and excavation have exposed the giant petrified redwoods, creating the natural museum we see today. Within the spectacular fossils are deposits of minerals, crystal, obsidian, wood opal, and silica. Out of the rock trees grow oaks, Douglas firs, red-bark manzanitas, bay laurels, toyons, and madrones. A half-mile trail loops around the natural displays of the major tree exposures. Interpretive signs describe the process of how living trees evolve into stone. On weekend mornings, a guided Meadow Walk is available. This extended hike leads to an area closed to the public. It departs from The Giant and heads northwest through a locked gate into the upper meadow. The trail visits an overlook of Mount Saint Helena and the 100-foot-high Ash Fall. The ash fall is rich with volcanic material, including tuff, iron, obsidian, pumice, and petrified wood chunks. The walk can extend to a fern and redwood forest by a tributary of Mark West Springs. Call for tour times. The privately owned park, declared a historical landmark in 1978, includes a museum, gift shop, and picnic areas. Leashed dogs are allowed on the trails."