Fires in Central South America
At the foothills of the Bolivian Andes, scores of fires were burning on October 12, 2005, when this image was captured. Actively burning fires, most likely linked to agriculture, are outlined in red; the atmosphere is thick with clearly-visible smoke to the East of the mountains.
Fire is still being used in some parts of the world to clear land of trees and shrubs for crops and to fertilize the soil. However, in many parts of the world (particularly the tropics), nutrients are mostly "locked up" in the trees; the underlying soil is nutrient-poor and therefore not suitable for agriculture.
So, after only a few years, the farmer using such methods is forced to move on and repeat the process elsewhere. If this happens over a large enough area, biodiversity becomes impoverished as wildlife species are forced to move on in search of more suitable habitat.
This process also impacts global warming: the burning of trees releases carbon dioxide, a "greenhouse" or heat-trapping gas into the atmosphere. On the other hand, natural or "wild" fire is an important, natural ecological process and is often caused by lightning strikes. These less frequent, smaller impact events create a mosaic of patches that contain a variety of tree sizes and ages, which in turn provides greater diversity of habitat for other species. Images such as this one are used by scientists to map the extent of fires and to target smaller areas for more intensive observation.