Wednesday, April 16, 2014

Amazon rain forest's biggest enemies are fire and climate change

James Maynard in Tech Times: The Amazon rain forest is facing dangers from climate change and droughts, which are leading to frequent wildfires in the ecosystem.  Fires are normally rare in the rain forest, due to thick tree cover that keeps the ground cool and wet.

Deforestation and climate change are combining to create "tinderbox" conditions in many areas of the Amazon, according to researchers from Penn State University. The ecosystem may reach a "tipping point" where fires create enough damage to make recovery difficult, new research reveals.

"We documented one of the highest tree mortality rates witnessed in Amazon forests. Over the course of our experiment, 60 percent of the trees died with combined drought and repeated fire. Our results suggest that a perfect firestorm, caused by drought conditions and previous fire disturbance, crossed a threshold in forest resistance," Jennifer Balch, an assistant geography professor at Penn State who led the study, said.

Over eight years, researchers set fire to plots of the Amazon rain forest, each of which was nearly 125 acres in size. By studying deaths of the trees, investigators were able to study how drought affects both the intensity of fire and tree mortality. The southeast area of the Amazon, where the experiment was performed, is especially vulnerable to climate change, according to the study.

The period of time during which the research was conducted included 2007, during which there was a severe drought in southeastern regions of the Amazonian rain forest. That year, fires destroyed 10 times more forest than in an average year, according to Douglas Morton at NASA. That amounts to an area the size of a million soccer fields....

Fires along the Xingu River, viewed by NASA

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