Several years ago, a professor of geoscience — known as the “Climate Detective” — came to Wimberley to spend a day in the Hill Country studying the old trees along the Blanco River. He found an ancient bald cypress that he believes dates back to 1426.
The professor studies the tree rings of the oldest living trees by extracting a long, very thin core from the tree — which quickly grows over and seals itself. The sample of the tree that was studied in Wimberley probably dates back to before 1426 as the core sample was not long enough to actually reach the center of the tree.
Studying tree rings is an art and a science. Analyzing the core sample can show where severe drought so inhibited growth in a certain year that there is no ring above the cellular level. Historical records show that a drought occurs every 10 years. However, the professor determined there was a period in the 1500s and another in the 1600s that made the most severe drought of record (in the 1950s) look wet. He believes the area will have at least one major drought every century, having studied the data and rainfall records dating back to the 19th century.
The Hill Country region’s growing population and development of ranchland into subdivisions puts much more pressure on scarce water resources. The tree ring should be a strong warning to policymakers and the public of the importance of water conservation. Drought periods are becoming more frequent and lasting longer. The old trees tell us what we all should already know: that drought is an inescapable part of life in the Southwest. It has been that way for centuries.
