We have previously reported a vast heterogeneity of carbon
stock and tree species diversity within the less studied dry zone
homegardens; results that contribute to more knowledge of their expansion
potential as well as climate change mitigation and adaptation
potential (Mattsson et al., 2015). In this study, we aim to investigate
the effects of tree size inequality and species diversity on aboveground
biomass, while accounting for the effects of stand quality and soil fertility.
We employed structural equation model (SEM; Malaeb et al., 2000)
to analyze data from 45 dry zone homegardens in Sri Lanka. Specifically,
we tested the following hypotheses, represented by SEM paths: 1) the
effects of stand quality and soil fertility on aboveground biomass, tree
size inequality and species diversity; 2) the indirect effect of stand quality
and soil fertility on aboveground biomass via tree size inequality and
species diversity, and 3) the direct effects of tree size inequality and species
diversity on aboveground biomass.