Featured Destination Story

Petrified Forest

Calistoga, CA

Deep in the rugged foothills of the Mayacamas Mountains, the Petrified Forest of Calistoga stands as a silent, stone-carved testament to a cataclysmic moment in Earth’s history. Located just a few miles from the steaming vents of Old Faithful Geyser, this site is famous for containing the largest petrified redwood trees in the world. Unlike many other petrified forests where the wood has been transported by water over long distances, the specimens here were preserved exactly where they grew millions of years ago. To visit this forest is to walk through a "fossilized snapshot" of a prehistoric ecosystem, frozen in time by the very volcanic forces that created the surrounding Napa and Sonoma valleys.

The geology of the forest dates back approximately 3.4 million years to the Pliocene Epoch. The preservation began with a massive eruption from nearby Mount Saint Helena, which unleashed a devastating pyroclastic flow—a fast-moving cloud of superheated ash and volcanic gas. This flow flattened the massive redwood forest, burying the trees instantly in a layer of ash that excluded oxygen and prevented decay. Over the ensuing millennia, silica-rich groundwater permeated the buried logs, gradually replacing the organic wood fibers with quartz crystals in a process known as permineralization. This slow chemical exchange was so precise that the intricate details of the wood—including bark textures and annual growth rings—were preserved in stone.