Size and frequency of natural forest disturbances and the Amazon forest carbon balance

Abstract

Forest inventory studies in the Amazon indicate a large terrestrial carbon sink. However, field plots may fail to represent forest mortality processes at landscape-scales of tropical forests. Here we characterize the frequency distribution of disturbance events in natural forests from 0.01 ha to 2,651 ha size throughout Amazonia using a novel combination of forest inventory, airborne lidar and satellite remote sensing data. We find that small-scale mortality events are responsible for aboveground biomass losses of ~1.7 Pg C y−1 over the entire Amazon region. We also find that intermediate-scale disturbances account for losses of ~0.2 Pg C y−1, and that the largest-scale disturbances as a result of blow-downs only account for losses of ~0.004 Pg C y−1. Simulation of growth and mortality indicates that even when all carbon losses from intermediate and large-scale disturbances are considered, these are outweighed by the net biomass accumulation by tree growth, supporting the inference of an Amazon carbon sink.

Citation

Espirito-Santo, F.D.B.; Gloor, M.; Keller, M.; Malhi, Y.; Saatchi, S.; Nelson, B.; Oliveira Junior, R.C.; Pereira, C.;Lloyd, J.; Frolking, S.; Palace, M.; Shimabukuro, Y.E.; Duarte, V.; Monteagudo Mendoza, A.; Lopez-Gonzalez, G.; Baker, T.R.; Feldpausch, T.R.; Brienen, R.J.W.; Asner, G.P.; Boyd, D.S.; Phillips, O.L. 2014. Size and frequency of natural forest disturbances and the Amazon forest carbon balance. Nature Communications. 5:1-6.