Range 
Total number of trees 3.9×10^11: median tree density 565 trees/ha: ~16,000 tree species

Organism 
Biosphere 
Reference 
ter Steege H et al. Hyperdominance in the Amazonian tree flora. Science. 2013 Oct 18 342(6156):1243092. doi: 10.1126/science.1243092. p.326 right column 3rd paragraphPubMed ID24136971

Method 
P.325 2nd paragraph: "The ~6millionkm^2 Amazonian lowlands were divided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify sampling error, was used to generate estimated Amazonwide abundances of the 4962 valid species in the data set. [Investigators] estimated the total number of tree species in the Amazon by fitting the mean rankabundance data to Fisher’s logseries distribution." 
Comments 
P.12430921 right column 3rd paragraph: "First, it [The rankabundance distribution (RAD) of [spatial model]] provides the most precise estimates yet of two numbers that have been debated for decades: How many trees and how many tree species occur in the ~6millionkm^2 landscape of Amazonia (refs 1, 3–5). [Investigators'] estimate of tree density yielded a total of 3.9×10^11 individual trees and a median tree density of 565 trees/ha (fig. S4). Assuming that [their] population size estimates for the common species are reasonable (fig. S5) and that Fisher’s logseries model fits [their] data (table S2 and figs. S6 and S7) (ref 1), [they] estimated the total number of tree species in the Amazon to be about 16,000 (Fig. 2). A second estimate based on the Fisher’s alpha scores of all plots yielded a similar figure: 15,182 species (fig. S8)." 
Entered by 
Uri M 
ID 
112912 