Architecture of four tree species from different strata of a semideciduous forest in southern Brazil

The present study was conducted in a semideciduous Brazilian forest to verify whether there were architectural differences during development among tree species that differ in adult stature, such that understorey species maximise light interception and canopy and emergent species maximise height gain to rapidly reach high light environments. The crown illumination index and light interception index of individual trees as well as the variation in form among the understorey species were also analysed. Two understorey, one canopy and one emergent species were chosen, and the individuals were divided into height classes. Architectural comparisons among individuals were evaluated using allometry; crown illumination and light interception indices were compared among species. All comparisons were made within each height class. The two understorey species presented some differences in growth form, but both exhibited greater investment in the crown than did the canopy and emergent species. The crown illumination index did not differ among species, but the light interception index was higher for the understorey species. The results indicated that architectural differences between the studied species arise predominantly because species belong to different strata of the forest. Comparison within height classes was important because it allowed us to evaluate species architectural characteristics throughout plant development that cannot be detected using a single height-class comparison or that can be neglected if individuals of different heights are compared.