Positive feedbacks in the fire dynamic of closed canopy tropical forests

The incidence and importance of fire in the Amazon have increased substanti ally during the past decade, but the effects of this disturbance force are still poorly understood. The forest fire dynamics in two regions of the eas tern Amazon were studied. Accidental fires have affected nearly 50 percent of the remaining forests and have caused more deforestation than has intent ional clearing in recent years. Forest fires create positive feedbacks in f uture fire susceptibility, fuel loading, and fire intensity. Unless current land use and fire use practices are changed, fire has the potential to tra nsform large areas of tropical forest into scrub or savanna.