Study: 320 million trees killed by Katrina

NEW ORLEANS, Nov. 16 (UPI) -- U.S. researchers say the millions of trees killed or severely damaged by Hurricane Katrina in 2005 have become a major source of carbon dioxide emissions.

Satellite data shows that an estimated 320 million large trees were killed or severely damaged on five million acres of forest across Mississippi, Louisiana and Alabama, NASA said Thursday in a release.

The report, published in the journal Science, said young growing forests play a vital role in removing carbon dioxide from the atmosphere by photosynthesis. The loss of the trees, combined with carbon dioxide released from decomposition of the dead wood, has resulted in a large carbon dioxide release into the environment.

"The loss of so many trees will cause these forests to be a net source of carbon dioxide to the atmosphere for years to come," said lead author Jeffrey Chambers, a biologist at Tulane University in New Orleans.

NASA said Chambers and colleagues from the University of New Hampshire in Durham, N.H., studied Landsat 5 satellite data captured before and after Hurricane Katrina to determine the damage to Gulf Coast forests.