July 1, 2009

Tree rings tell tale of weather history

Researchers say baldcypress trees in central Texas provide a record of past weather and clues to the region's future.

Malcolm Cleaveland of the University of Arkansas and his team have been taking cores from the trees that show the rings, the Austin American-Statesman reported Tuesday. Each ring represents a year in the tree's life, with thin ones being years of drought and thicker ones those when rainfall was more plentiful.

The tree rings give you a perspective you can't get in any other way, Cleaveland said.

The baldcypress has two big advantages: the wood is soft so cores are relatively easy to obtain and the trees live for hundreds of years. The coring does not harm the tree.

In the 1940s and 1950s, the region had a 10-year drought that has become the standard for water management. Cleaveland's research, still in its early stages, has found many longer droughts, like one in the 16th century that endured for 40 years.

Todd Votteler, project manager for the Guadalupe-Blanco River Authority, said a 40-year drought is something the state is not ready for.