Our study revealed that aboveground biomass substantially increased
with tree size variation only, which supports the niche complementarity
mechanism. However, aboveground biomass was not
considerably increased with species diversity, stand quality and soil fertility,
which might be attributable to the adaptations of certain productive
species to the local site conditions. Our results suggest that stand
structure shaped by few productive species or independent of species
diversity is a main determinant for the variation in aboveground biomass
in dry zone homegarden agroforestry systems. Maintaining DBH
variation through different management practices, in order to alter the
relative yields or individual performance of nonproductive species,
could be an effective approach for enhancing aboveground biomass in
these homegarden agroforestry systems.