Contributions of Leguminosae to young and old stands of neotropical forests under different environmental conditions

Abstract

Potentially nodulating Leguminosae species had high density and biomass in young stands of forests in Northeast Brazil, except in a dry forest on a low-fertility soil. Leguminosae species, especially potentially nodulating ones, appear to be important components of tropical secondary forests, although information is still scarce concerning their contributions to richness and biomass under different environmental conditions. To evaluate the contribution of Leguminosae to the aboveground biomass and density of young and old forest stands in six sites, with different climate and soil conditions, in northeastern Brazil. The biomass of plants was estimated using allometric equations in ten plots in one young and one old forest stand in each site. Leguminosae were separated into nodulating and non-nodulating species based on literature. Leguminosae, mainly nodulating species, displayed the largest number of species among all families and the largest biomass and density in young stands. There was more similarity in Leguminosae species composition between young and old stands in dry than in humid forests. Nodulating species make considerable contributions to the biomass of the initial successional stages of forests in Northeast Brazil — confirming the importance of the family for natural forest regeneration, especially in dry environments.