Researchers for the first time mapped the extent and frequency of understory fires across a study area (green) spanning 1.2 million square miles (3 million square kilometers) in the southern Amazon forest. Fires were widespread across the forest frontier during the study period from 1999-2010. Recurrent fires, however, are concentrated in areas favored by the confluence of climate conditions suitable for burning and ignition sources from humans.
NASA's Earth Observatory
07.06.13
<a rel="nofollow" class="external free" href="http://www.nasa.gov/topics/earth/features/amazon-fire-risk.html">http://www.nasa.gov/topics/earth/features/amazon-fire-risk.html</a>