Vegetation C was calculated by multiplying the average biomass
and C: biomass ratio of the corresponding species. When only
aboveground biomass was reported, we estimated belowground
biomass using the belowground/aboveground biomass ratio
(BG:AG) derived for the same species, and calculated total plant
biomass. BG:AG ratio varied with geographical factors. To improve
accuracy, we estimated the BG:AG ratio of a specific species in each
province using the published literature data (with belowground
and aboveground biomass measured at the same time) in the same
province.