The Mystery of the Fallen Trees

The Mystery of the Fallen Trees

  • Submitted By: samn13
  • Date Submitted: 09/01/2008 9:12 PM
  • Category: English
  • Words: 422
  • Page: 2
  • Views: 643

When Hurricane Katrina smashed into the Gulf Coast with all the fury of a woman scorned, blasting 300 miles of shoreline from Pensacola, Florida, to Terrebonne, Louisiana, and reaching some 200 miles inland, she knocked down or badly damaged 320 million large trees across an area the size of Maine, according to data collected by Tulane University biologist Jeffrey Q. Chambers and his colleagues. As those dead and dying trees decay, they will release yearly into the atmosphere about 5 million tons of carbon dioxide, one of the principal greenhouse gases, and contribute—perhaps—to the cycle of global warming.

Trees absorb carbon dioxide during photosynthesis and release it during respiration and after they die and decompose. In the United States, trees absorb an estimated 100 million tons of the gas each year—about the same amount that will be released during the next two decades by the trees Katrina killed or damaged. The amount released by the dead trees, Chambers says, may not be enough to affect global warming today. However, he adds, if hurricanes become more frequent and more severe in a warmer world, as climate scientists have predicted, then damage like that caused by Katrina could “start pushing ecosystems toward the respiration side” of the carbon dioxide equation. This process would lead to a net gain in the greenhouse gas and thus contribute to global warming, which in turn would generate more severe storms. The potential for this self-perpetuating cycle is speculative at the moment, however: “We don’t really know where we’re going,” Chambers says.

Exacerbating the problem is that no one can predict what will happen to the downed forests. Two hundred years ago, Chamber says, the trees would have regrown into carbon dioxide-absorbing forests, but today nonnative invasive species, such as Chinese tallow trees, move into disturbed areas and “expand drastically.” How the alien species will affect forest recovery remains unknown. Moreover, if...

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