skip navigation

Fire Update

We are currently closed due to the Tubbs fire. Click here for more information.

A Brief History of the Petrified Forest

What has been described as one of the finest examples in the world of an ancient forest is preserved here at the Petrified Forest, in Calistoga, California. This unique site at the gateway to the Napa Valley was created following a violent volcanic explosion 3.4 million years ago. Seven miles northeast of this property lies the remains of an extinct volcano that today we call Mt. St. Helena. The incredibly powerful blast knocked down the forest of now extinct Redwood trees (Sequoia Langsdorfii) in a SW-NE orientation. Thick layers of volcanic ash billowing from the volcano rapidly buried the trees, creating an anaerobic (oxygen deprived) environment which discouraged the presence of the bacteria that decompose organic material. The thousands of years following the event were characterized by the formation of mineral-rich water which percolated through the ashy deposits, saturating the pores of the organic tissues of the Redwoods with silica, moving it through the cellular spaces. During this process the saturated water evaporated, and the excess minerals were deposited in the cells and tissues, creating a three-dimensional fossil through the process of permineralization, and perfectly presevering even the most minute detail of the wood.

The petrified trees at this site remained buried for 3.4 million years until, in 1870, an intrepid Swedish homesteader by the name of Charles Evans (“Petrified Charley”), while raking his pasture, discovered the top of an old hollow log that was as hard as stone. His initial curiosity led a number of scientists to visit the property in order to learn more about these natural wonders in California. One such visitor was the famed American paleontologist O.C. Marsh. Through his observations of the site, and the analysis of the petrified wood back at Yale University, he wrote "A Fossil Forest in the Tertiary of California," published in The American Journal of Science and Arts in 1871. These initial studies of the petrified forest were continued in the late 1920s by world renowned paleobotanist Ralph W. Chaney from U.C. Berkeley, who wrote “Redwoods of the Past”, which started a career long study of Redwoods in the fossil record. This collaboration with U.C. Berkeley continues today, allowing us to further develop our understanding of this petrified forest as it is today, as well as teaching us about the environments of the past. In later years, petrified Pine and Oak trees were discovered on the outer edges of the ancient Redwood forest. Associated with the petrified trees are fossil leaf impressions of numerous other conifers and hardwoods. This includes needles of Spruce, Douglas Fir, and Hemlock and broadleaves of Alder, Myrtle, Tan Oak, California Laurel, Rhododendron, and Huckleberry, as well as a new species of Oak (Quercus Bockeei) named after the owner Ms. Ollie Bockee who discovered it during excavation of the Tunnel Tree and which was later identified in 1930 by Erling Dorf, a noted geologist and Professor at Princeton University.

Through the years, the Petrified Forest has also been a sanctuary and place of interest for many other notable individuals. In 1880, Robert Louis Stevenson recorded his visit to the Petrified Forest in his book “The Silverado Squatters,” while exploring the local environments with his new wife, Fanny Stevenson. Luther Burbank, one of the most important horticulturalists the world has ever known, also took time out of his busy schedule to contribute to our understanding of the Petrified Forest. During his visits he assisted in the study of a number of our native plants and trees on the property, and helped dedicate a large piece of petrified wood to Central Park in New York.

Since the time of Charles Evans, this incomparable property has passed through several different owners, but it was not until Ollie Bockee purchased the land in 1914 that the park really started to take shape as we see it today. Ollie came in with the vision of creating a site with the goals of scientific discovery, preservation, and education moving into the future. Her family have now owned, managed, and expanded this property for over one hundred years, passing on their knowledge and passion for the land, and a preservation ethic and educational philosophy that still stands strong today. In celebration of their hard work and dedication, the family held a one hundredth anniversary celebration in 2014. The family looks forward to the continued sharing and celebration of the Petrified Forest as we begin the next one hundred years. We look forward to you joining us for the adventures to come.