UT Researchers' Work Reveals 220-year Hurricane History

KNOXVILLE -- New research by two University of Tennessee professors could help us better understand hurricanes by looking to an unusual source: tree rings.

By analyzing the rings of trees in areas that are hit by hurricanes, UT professors Claudia Mora and Henri Grissino-Mayer have found that the oxygen isotope content in a ring will vary if the tree was hit by a hurricane during that year.

Their research is being published in this week's early online version of the Proceedings of the National Academy of Sciences, one of the world's most cited multidisciplinary scientific journals.

There has been a significant increase in the number of hurricanes hitting the Southeast since the mid-1990s, and scientists have sought to determine the cause for the upswing. Some question exists about whether the increase is part of a regularly occurring cycle of activity, or whether it is being brought about by a cause such as global climate change.

The problem facing this analysis is that the current documented history of hurricane activity in the Southeast dates back only about 100 years -- not enough time to establish a cycle that might last many decades at a time.

By looking at older trees, Mora and Grissino-Mayer have been able to create a record of hurricane activity dating back 220 years, more than double the current record.

"We think this can shed light on whether we're looking at a long-term pattern, or something that could be caused by human activity," said Mora, professor and head of UT's Department of Earth and Planetary Sciences.