Understory fires represent an accelerating threat to Amazonian tropical forests and can, during drought, affect larger areas than deforestation itself. These fires kill trees at rates varying from < 10 to c. 90% depending on fire intensity, forest disturbance history and tree functional traits. Here, we examine variation in bark thickness across the Amazon. Bark can protect trees from fires, but it is often assumed to be consistently thin across tropical forests. Here, we show that investment in bark varies, with thicker bark in dry forests and thinner in wetter forests. We also show that thinner bark translated into higher fire‐driven tree mortality in wetter forests, with between 0.67 and 5.86 gigatonnes CO2 lost in Amazon understory fires between 2001 and 2010. Trait‐enabled global vegetation models that explicitly include variation in bark thickness are likely to improve the predictions of fire effects on carbon cycling in tropical forests.
Forest fires in the Amazon: short-term individual benefits versus long-term societal costs
Forest fires in the Amazon: short-term individual benefits versus long-term societal costs
Fire is the least expensive and most broadly used method of clearing land and converting forest biomass into soil nutrients for pastures and crops in the tropics. Fire is also used to control weeds and to reinvigorate palatable pasture grasses. Even if beneficial for farmers over the short run, intensification of deforestation and burning impose long-term costs on individuals and society.