Yellowstone’s Petrified Tree

If you do not feel like taking a grueling all day hike to reach a petrified forest, Yellowstone’s petrified tree might be the thing to see. It is a short drive from village of Tower-Roosevelt and can be seen from the road, just off Yellowstone Grand Loop Road.

Fifty million years ago the tree was a living redwood like the redwoods of California. At that time what is now Yellowstone had a warmer, almost subtropical climate, and rain was frequent.

“Petrified” comes from the Greek “petros” and the Latin “petra”, meaning stone or rock. A living thing becomes petrified, or silicified, when it is turned to stone. The tree was covered in ash when a series of volcanoes erupted, spewing volcanic ash that contained silica. Silca, or silicon dioxide, filled up the living cells, turning them to rock

Silica is a hard substance making up sand and quartz. It is used to make glass, porcelain, and cement. It also dissolves in water quickly. All living cells contain water, so it is easy to see how silica could become dissolved in living cells and turn them to stone. Much of a tree’s substance is composed of an organic molecule called cellulose, a substance made up of glucose, the sugar from which we all get energy. When cellulose is infiltrated with silica, the tree’s organic compounds are replaced with minerals and petrification becomes complete.

There used to be three petrified trees in the area, but souvenir-stealing tourists destroyed the other two. Now there is a fence to protect the remaining petrified tree.