Under normal circumstances, a tree trunk takes decades or even centuries to decompose. At first, insects take to the tree and burrow in, detaching the first layers of bark and facilitating the passage of other insects and mushrooms. This is also when microbial decomposition sets in. Next, pieces of wood begin to separate from the trunk. Bacteria, fungi, and insects continue to occupy the tree. Finally, the humidification phase begins: the wood crumbles and becomes part of the forest floor.

The Calistoga Forest had a very different fate. 3.4 million years ago, the Mount St. Helena volcano, located 7 miles miles away, violently erupted and broke the surrounding calm. It’s devastating blast knocked down the trees in the area and covered them with a thick layer of ash, depriving them of oxygen. Without air, bacteria cannot grow and break down wood. Thousands of years passed during which water rich in minerals slowly passed through the sediment layer and penetrated the wood. During this long process, the water evaporated and the minerals remained, deposited in the cells and tissues of the trees. This resulted in the creation of entirely fossilized material that preserved the finest details of the wood. This is how our trees were transformed into stone, defying time.