EXTREME RADIAL CHANGES IN WOOD SPECIFIC GRAVITY IN SOME TROPICAL PIONEERS

Twelve Hampea appendiculata, six Heliocarpus appendiculatus , and twelve Ochroma pyramidale trees from tropical wet forest in Costa Rica were sampled across their radii. Wood from all three species increased linearly in specific gravity from pith to bark. The magnitude of the increase was about 0.1 units of specific gravity per 10 cm of radius, although there were differences between the species and between trees within each species. All three species colonize clearings and disturbed sites, and these extreme changes in specific gravity may be associated with the pioneer habit in the wet forest.