Positive Feedbacks in the Fire Dynamic of Closed Canopy Tropical Forests

Abstract

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

Detecting anthropogenic disturbance in tropical forests

“…Surface fire disturbance Logging disturbance often paves the way for surface fires, which have affected millions of hectares of Amazonian forests in recent years [7,13] with devastating effects on the flora and fauna (e.g. [14]).…”

Ecosystem decay of Amazonian forest fragments: implications for conservation

“…Leaf litter accumulates near edges (Carvalho and Vasconcelos 1999 Edge penetration distance (m) Didham and Lawton 1999) because drought-stressed trees shed leaves and possibly because drier edge conditions slow litter decomposition (Kapos et al 1993, Didham 1998, Vasconcelos and Laurance 2005. Accumulating litter may negatively affect seed germination (Bruna 1999) and seedling survival (Scariot 2001) and makes forest edges vulnerable to surface fires during droughts (Cochrane et al 1999). One of the most striking edge effects is a sharp increase in rates of tree mortality and damage Laurance 1997, Laurance et al 1998b).…”

Synergies across a REDD+ landscape: Non-carbon benefits, joint mitigation and adaptation, and an analysis of submissions to the SBSTA

“…The frequency and intensity of wildfires in many forests have been increasing. For example, some Amazonian regions are now affected by fire every 5-15 years (Alencar et al 2006) instead of the former fire rotation thought to be in the hundreds or thousands of years (Cochrane et al 1999). In ecosystems not adapted to fires, or those where regrowth does not match the biomass lost in the fire, fires can reduce ecosystem services such as carbon storage (IPCC 2014b).…”