Abstract ID: 715

Does the disturbance hypothesis explain biomass increase results found in basin-wide Amazon forest plot data?

In 1998 Phillips et al. reported positive large-scale above-ground biomass trends in old-growth forests across the Amazon basin, thought to reflect a large-scale response to exterior forcing. Their finding has been criticized as being an artefact due to an inherent sampling bias induced by the nature of forest growth dynamics. Here we characterize statistically the disturbance process in Amazon old-growth forests as recorded by the RAINFOR forest plot census network and independent research programs (135 plots) and then explore its consequences using a simple purely data-based stochastic simulator. Over the observed range annual above-ground biomass losses follow an exponential probability distribution possibly tending to a power law for largest events. Simulator results reveal skewed biomass gains distributions for short periods. Nevertheless sampling biases are too small to explain the gains detected by the extended RAINFOR plot network. The results thus lend further support that basin-wide net biomass gains are real.

Session:  Biodiversity - Permanent plot networks for inventory of biodiversity and carbon stocks: integrating taxonomic and ecosystem objectives.

Presentation Type:  Oral