Trees felled by Katrina weighed as factor in global warming
By John Pope, in the Times Picayune
Saturday, November 24, 2007

As if Hurricane Katrina's wind and water hadn't inflicted enough
damage, a group of researchers led by a Tulane University biologist
has found that the monster storm may well have accelerated global
warming.

When Katrina roared through coastal forests in August 2005, it
destroyed thousands of trees. As those trees decompose, the carbon
they release will be enough to offset a year's worth of new tree
growth in other parts of the United States, said Jeffrey Chambers, an
assistant professor of ecology and evolutionary biology. The team's
report has been published in the peer-reviewed journal Science.

Forests are important adversaries of global warming because they
remove carbon from the atmosphere during photosynthesis, thereby
lowering the production of carbon dioxide. However, an increase in
this compound warms the climate, resulting in more intense storms and,
eventually, more trees that will decompose, the scientists found.

The Tulanians collaborated with researchers from the University of New
Hampshire.

http://www.nola.com/news/t-p/metro/i...680.xml&coll=1

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The abstract for the article is Science is at:
http://www.sciencemag.org/cgi/conten.../318/5853/1107

It says:

Science 16 November 2007:
Vol. 318. no. 5853, p. 1107
DOI: 10.1126/science.1148913
Brevia
Hurricane Katrina's Carbon Footprint on U.S. Gulf Coast Forests
Jeffrey Q. Chambers,1* Jeremy I. Fisher,1,2 Hongcheng Zeng,1 Elise L.
Chapman,1 David B. Baker,1 George C. Hurtt2
Hurricane Katrina's impact on U.S. Gulf Coast forests was quantified
by linking ecological field studies, Landsat and Moderate Resolution
Imaging Spectroradiometer (MODIS) image analyses, and empirically
based models. Within areas affected by relatively constant wind speed,
tree mortality and damage exhibited strong species-controlled
gradients. Spatially explicit forest disturbance maps coupled with
extrapolation models predicted mortality and severe structural damage
to ~320 million large trees totaling 105 teragrams of carbon,
representing 50 to 140% of the net annual U.S. forest tree carbon
sink. Changes in disturbance regimes from increased storm activity
expected under a warming climate will reduce forest biomass stocks,
increase ecosystem respiration, and may represent an important
positive feedback mechanism to elevated atmospheric carbon dioxide.

1 Ecology and Evolutionary Biology, Tulane University, 400 Lindy
Boggs, New Orleans, LA 70118, USA.
2 Institute for the Study of Earth, Oceans, and Space, University of
New Hampshire, Durham, NH 03824, USA.


* To whom correspondence should be addressed. E-mail:



-.-. --.- Roger