|Anthropogenic factors that can affect forests include logging, human-caused forest fires, acid rain, and introduced species, among other things.
There are also many natural factors that can also cause changes in forests over time including forest fires, insects, diseases, weather, competition between species, etc. In 1997, the World Resources Institute recorded that only 20% of the world's original forests remained in large intact tracts of undisturbed forest. More than 75% of these intact forests lie in three countries - the Boreal forests of Russia and Canada and the rainforest of Brazil. In 2006 this information on intact forests was updated using latest available satellite imagery.
Satellite observation of smoke plumes from wildfires revealed that the plumes could be traced intact for distances exceeding 5,000 kilometers. This observation suggests that the plumes were in the stratosphere above weather conditions that would have brought the plume back to earth.
Atmospheric models suggest that these concentrations of sooty particles could increase absorption of incoming solar radiation during winter months by as much as 15%.
The massive forest fire in Indonesia (1997/1998) released approx. 2.57 gigatonnes of Carbon Dioxide into the atmosphere (source: Nature magazine, November 2002). During 1997-1998, the total amount of Carbon Dioxide released to the atmosphere was 6 gigatonnes. Most of the Carbon Dioxide gas is released by the continuous underground smouldering fire on the peat bogs.
(parts source : wikipedia)
Labels: fires, forest, wildfire