A tree's annual growth cycle creates a record of good seasons—and poor ones. Analyzing ring patterns in living and dead wood can help scientists date ancient ships or reconstruct changing climates.

In the U.S. Southwest researchers rely on tree rings to track changes in the seasonal monsoon rains that deliver about half of New Mexico and Arizona's precipitation. In the June issue of Scientific American Connie Woodhouse, associate professor in the School of Geography and Development at the University of Arizona, describes what the annual rings reveal.

Woodhouse and two Arizona graduate students give a behind-the-scenes look at the institution's Laboratory of Tree-Ring Research in this video by Arizona Public Media. They describe the ongoing monsoon project that matches tree ring data with instrumental records to reveal how rain cycleshave shaped life in the Sonoran Desert.