Abstract
The associations of tree species with physical (edaphic and/or topographic) habitats in species-rich tropical forests, and interspecific differences in their habitat association are commonly observed. One would therefore expect tree species to have developed numerous anatomical and physiological adaptations to specialized habitat conditions in a niche where the species regenerate preferentially. A wide variation among seedlings of tropical tree species in the morphology of roots has been observed. The variation in root architecture and allometry of tropical tree seedlings may be explained by trade-off between depth growth for the uptake of water which increases with depth and horizontal growth around the soil surface for the uptake of nutrients which tend to lie close to the soil surface. Therefore, it is hypothesized that architectural and allometric variations in roots generate competitive advantage of a species over counterpart competitors in a habitat where the species regenerates preferentially and in turn lead to equilibrium coexistence of tree species in forest communities.
