Within the genus, model 3 does not give effect over model 1
since b coefficient does not significantly influence the model
(Table 1). However, adding wood density as a predictor is an
alternative to estimate the biomass of big trees and mixed species.
The b coefficient is significant when wood density is incorporated
into mixed species and the average deviation decreases. The effect
of wood density to the dry weight is evident for big trees from the
current data set as explained previously and from the different
data set of Brown as explained in the next paragraph