Hyperdominance in Amazon carbon cycling - which tree species contribute most to the Amazon forest carbon cycle?

We have a new paper in Nature Communications this week, led by Sophie Fauset of the University of Leeds and involving the broad RAINFOR consortium of forest inventory plots  across Amazonia. This paper looks at which tree species contribute most to the biomass and woody productivity of the Amazon forest. It is a follow up to the paper led by Hans ter Steege in 2013, which showed that only 227 tree species (out f about 16,000) contributed half of trees in Amazonia. In this paper we look at how many trees contribute to biomass and productivity - in this case it is not just the number of trees that matter, but also how big they get. We find that just 182 species contribute 50% of biomass, and 184 species contribute 50% of woody growth. As this study is based on "just" 500 plots, we are hesitant to to say the species ranking is 100% final, but top of the list is Iriatea deltoidea, a palm widespread across western Amazonia. Several other palms also feature in the top few. A noticeable contribution near the top of the list is the majestic Brazil nut tree  Bertholletia excelsa, which is common and grows to a huge size but can struggle to regenerate. Is this high abundance natural, or a legacy of millennia of human use of this tree across the Amazon?
 



Fauset, S. et al. Hyperdominance in Amazonian forest carbon cycling. Nature Communications 6:6857 doi: 10.1038/ncomms7857 (2015). Supplementary Information