The exotic Sonneratia apetala and native Kandelia obovata have been widely planted in mangrove afforestation and reforestation programmes in China. However, their capacity for carbon sequestration is still controversial.
The total vegetation biomass was highest in K. obovata monoculture, followed by the mixed forest and lowest in S. apetala monoculture. Such difference is attributed to the inconsistency by means of stem density of forests. This trend also applies to total vegetation and soil organic carbon storages.
Contrary to the original expectation, shrubby native K. obovata may be preferred to exotic S. apetala for mangrove carbon-based reforestation/afforestation prgrammes. It is recommended the carbon storage capacity of the existing S. apetala plantation may be enhanced by introducing native mangrove species. As an optional strategy of mangrove rehabilitation, the establishment of mixed plantations with different stem densities could improve the capacity of carbon storage for mono-specific plantations dominated by exotic species in Southern China.