FIRE FORECAST FOR THE AMAZON

[Reproduced from www.oeco.org.br]

The video shows an understory fire 
http://www.youtube.com/watch?feature=player_embedded&v=6Cjokcwp6-0

For the first time, researchers mapped the extent and the frequency of understory fire.
This week, American scientists released two studies that increase the concern with the next drought in the Amazon.
The prediction that the fires will be more severe than in previous years, adds up to data that stress the destructive potential of the flames. In years of large fires, the fire of the understory, one that spreads slowly and hidden under the canopy of trees, is able to achieve larger areas than the deforestation in the region.
The fire of the understory is not directly detected by satellites that monitor the Amazon. But in a study published in April in the journal Philosophical Transactions of the Royal Society B, scientists from Nasa, the American space agency, used data obtained by the Modis on the destruction caused by the fire and the recovery of the forest.
Fire-stricken areas present in consecutive years, show signs of recovery, unlike deforested areas that do not recover in the next few years. The pattern of damage and recovery over the years provides the necessary information for scientists to identify the effects of fire in the understory.
Between 1999 and 2010, over 85.5 thousand square kilometers were consumed by the fire of the understory, according to Nasa data. This number represents 2.8 of the total forest area. The fire in the understory advances on average at a rate of 0.5 metre per minute, well slower than in Savannah, for example, whose speed is 100 m. In addition, unlike shrubs and grasses of the savannah that can survive low-intensity fires, trees of the Amazon are not adapted to fire. The long and slow burning is able to cause a mortality that can range from 10 to 50 trees of the affected area.
The study also demonstrates that the risk of fire is not associated directly to deforestation, but climatic conditions.
In 2003 and 2004, for example, when we recorded high rates of deforestation, the natural forests near deforested regions were little affected by fire.
Understory fire activity coincides with low night humidity, measured by AIRS (Atmospheric Infrared Sounder), Acqua, satellite instrument.
"You can look inside the Indian reservations, where there is no deforestation and see huge fires of understory", says Doug Morton, of Nasa's Goddard Center. "The human presence on the border of deforestation increases the risk of forest fires, when conditions are favorable to the fire, with or without deforestation activity". According to him, the spark can come from stoves, camping, cigarettes, cars, uncontrolled burning and numerous human activities.

Fire forecast for the Amazon (source: NASA).