The science of dating trees

I attended an outdoor lecture at the Congaree National Park last month, an appropriate site as Dave Stahle, Professor of Geography at the University of Arkansas, and the world’s authority on bald cypress gave the talk, and the Park is home to the state-record holding cypress tree. Stahle takes very small and minimally damaging core samples from trees and studies them to age trees and document climate change -- he has sampled trees that are two thousand years old. The science of dendrochronology is studying information derived from tree ring growth. These ring samples allow to date exactly what years had normal, above normal, or subnormal rainfall as the rings are larger or very small depending on how much the tree grew. In our part of the country, bald cypress are the oldest trees and provide the most information.