Katrina's surge up the Pearl River damaged or killed many thousands of trees, and the tons of debris left to rot is slowly spewing greenhouse gases into the atmosphere, according to new research released Thursday by Tulane University.
The scientists, led by Tulane ecologist Jeffrey Chambers, hand-counted trees along the river and compared satellite images from before and after the storm to identify damage hot spots. From their data, published in the journal Science, Chambers said trees felled in just a few hours in a small area would decay, eventually releasing enough carbon gases to erase what every healthy forest in the United States could suck up in a year.
It was surprising, he said, "that one storm could essentially offset the gains for an entire year."
Should climate-change predictions of stronger and more frequent hurricanes be true, and more trees suffer Katrina-level beatings, the role of forests as a moderator of greenhouse gases could reverse, he said. Healthy forests are a "carbon sink," pulling in more greenhouse gases than they release during natural decay. Katrina's damage has had the opposite effect, Chambers said.
Large swaths of decaying trees could one day add to global warming.
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