Reference: Pan-tropical species groups

Methods and data for pan-tropical growth estimation

The underlying thesis of MYRLIN is that diameter increment patterns for tropical forest species have broad similarities from region to region. This allows general assumptions to be made about growth rates in the absence of direct observations from permanent sample plots.

This section presents the empirical basis for this approach. It presents summaries of species mean increment and typical size data from four regions: Eastern Amazonia, Northern Costa Rica, Papua New Guinea, and Guyana. These are shown in both graphical and tabular form. The tables list about 100 of the most common species from the PSPs in each zone, with their growth statistics.

For each regional data set, the species are grouped using a simple ordination technique. A detailed description of the method is given. It allows a common set of group seeds to be applied to each region, but the actual result will depend on the local distribution of species frequency-increment-size relationships. Using 16 standard 'seed' groups (designated by the letters A-S with I,O and Q not used), common patterns emerge, which form the basis for a generalized analysis.

In the general analysis, the data are standardized using the local mean increment and mean size of all species, except for those of Guyana. The grouping is re-applied to these standardized data to form general pan-tropical groups. The group characteristics are illustrated by reference to key species from the regions to show typical ecological and wood properties. The predictive power of the method is tested by its accuracy in predicting the Guyana group means.