CO2 may help some trees weather ice storms

U.S. scientists say higher levels of carbon dioxide predicted for later this century might help reduce damage to some trees caused by ice storms.

Researchers working at a Duke University outdoor test facility found commercially important loblolly pines, growing under carbon-dioxide levels mimicking those predicted for the year 2050 -- roughly one and a half times today's levels -- fared somewhat better during and after a major ice storm than did loblollies growing under current concentrations of the gas.

The results came as a surprise, the researchers said.

"Before the storm, I was absolutely certain the pines would be more susceptible to ice damage under elevated concentrations of carbon dioxide," said Ram Oren, a Duke ecology professor. "My impressions were absolutely wrong. Instead of increasing the sensitivity to ice-storm damage, carbon dioxide decreased the sensitivity."

The scientists cautioned, however, they were not able to identify the actual mechanisms that helped to protect the trees grown under elevated carbon-dioxide conditions. "We just couldn't tease out anything obvious," McCarthy said.

The findings are reported in the Journal of Geophysical Research.

Copyright 2006 by United Press International