Ancient Wood Uncovered
Toppled by an eroding stream bank, a large sycamore, leaves still green, slumps low over the water, nearly blocking the channel. Farther downstream, another fallen tree helps to create a pool that shelters a catfish. But this tree fell into the stream 12,000 years ago!
As long as trees have grown beside streams, they have succumbed to the action of floods and currents. Rushing water scours soil away from the roots, undercutting the trees until they eventually fall into the stream. Every year, stream currents gather together jumbles of tree trunks and branches. Some of this wood becomes buried in sediments, where it is preserved for centuries, or even millennia.
Ancient wood, wood that was formed in trees that lived thousands of years ago, was recently found in a Missouri stream by Steve Peterson, who farms in north Missouri, and his son, Doug. They noticed that the creek running through their farm was uncovering buried tree trunks as it chewed into a nearby field. Curious about where the trees came from, Doug contacted the Forestry Department at the University of Missouri-Columbia.
The wood being uncovered at the farm ranged from nearly whole oak trees to small, very soft elms. All looked unusually old. Some of the wood was buried under at least 15 feet of soil in the creek bank, some lay on sand bars, and some was buried in the main channel. A forestry professor, Richard Guyette, took wood samples for carbon-dating and tree-ring dating to determine their age.
Results from the lab confirmed that the wood was from trees that had grown thousands of years ago. This finding led Guyette and Professor Dan Dey to age wood samples from various Missouri streams. They found a white oak tree in Hinkson Creek, which flows through the city limits of Columbia, that was 4,425 years old. They determined that most of the larger streams in Missouri have wood that is more than 2,000 years old. Some ancient wood can be found in most Missouri streams.
The tree species and genus of ancient wood can be identified by examining the cellular structure of the wood under a microscope. Guyette has identified ancient wood as having come from many tree species, including bur oak, swamp white oak, red oak, elm, black walnut, birch, willow and cottonwood.
Based on the wood samples, oaks apparently were common and widely distributed throughout Missouri bottomlands. In some