Data from: Tree species richness increases ecosystem carbon storage in subtropical forests

Forest ecosystems are an integral component of the global carbon cycle as
they take up and release large amounts of C in short time (C flux) or
accumulate it over longer time (C stock). However, there remains
uncertainty about whether and in which direction C fluxes and in
particular C stocks may differ between forests of high vs. low species
richness. Based on a comprehensive dataset derived from field-based
measurements, we tested the effect of species richness (3–20 tree species)
and stand age (22–116 years) on six compartments of above- and belowground
C stocks and four components of C fluxes in subtropical forests in
south-east China. Across forest stands, total C stock was 149 ± 12 Mg ha-1
with richness explaining 28.5% and age explaining 29.4% of variation in
this measure. Species-rich stands had higher C stocks and fluxes than
stands with low richness; and, in addition, old stands had higher C stocks
than young ones. Overall, for each additional tree species the total C
stock increased by 6.4%. Our results provide comprehensive evidence for
diversity-mediated above- and belowground C sequestration in species-rich
subtropical forests in south-east China. Therefore, afforestation policies
in this region and elsewhere should consider a change from the current
focus on monocultures to multi-species plantations to increase C fixation
and thus slow increasing atmospheric CO2 concentrations and global
warming.