Ginkgo Petrified Forest: Fifteen Million Years Frozen in Basalt

About fifteen million years ago, central Washington was an entirely different place. The region was warm and humid, covered by swamps and shallow lakes ringed by forests of ginkgo, maple, walnut, oak, sycamore, and swamp cypress, trees you might now associate with the Carolinas or East Asia. Then the Columbia River Basalt flows began. Lava poured across this landscape repeatedly, burying the forests under layers of volcanic rock. As the wood was sealed in place, groundwater rich in silica slowly replaced the organic material cell by cell. Over millions of years, the trees turned to stone.

Highway workers first noticed the petrified wood here in nineteen twenty-seven, but the significance of the site went unrecognized for four more years. In nineteen thirty-one, a geologist named George F. Beck, from what is now Central Washington University brought his students out to investigate. They identified dozens of species of prehistoric trees preserved in the basalt. Among them were specimens of petrified ginkgo, the first ever found anywhere in the world. The ginkgo is an ancient species, sometimes called a living fossil, but the tree was thought to have retreated from North America millions of years ago. Here, frozen in rock, were proof that ginkgoes had once flourished in what is now the high desert of Washington State.

In nineteen thirty-five, the Civilian Conservation Corps established a camp here. Workers from Company nine thirty-five, and later Company three thousand two hundred twenty-four, constructed trails, a museum building, and a caretaker's residence, developing the site that became Ginkgo Petrified Forest State Park. Their hand-built Trailside Museum, featuring a relief map and interpretive panels, still anchors the visitor area.

Today the park protects one of the most diverse assemblages of petrified trees on Earth, more than fifty species catalogued so far, in a landscape that looks nothing like the ancient forest it once was.