Carbon storage of a tropical mangrove forest in Mui Ca Mau National Park, Vietnam

• Carbon (C) storage in the mangrove forest of Mui Ca Mau National Park is quantified.
• Mean ecosystem C storage was 762.2 ± 57.2 MgC ha− 1.
• Deep C-rich sediment pool accounted for > 80% of ecosystem C storage.
• Total ecosystem C storage was 10.3 (± 0.8) × 106 MgC, indicating a large C sink.
• Removal of mangroves would lead to release of large potential CO2e to the atmosphere.

Mangrove forests constitute the most important sink of carbon (C) in the tropics, the conservation of which is an essential mean in offsetting C emissions and climate change. Mangrove forests are therefore suggested to be an important component of reducing emissions from deforestation and degradation (REDD +) schemes, which require scrupulous quantification of ecosystem C storage in order to monitor temporal C sequestration and emissions. Despite this, proportionally less is known about ecosystem C storage of mangrove forests in Vietnam, where these systems constitute a large proportion of its coastline. In this study, ecosystem C storage of a tropical mangrove forest in Mui Ca Mau National Park, Vietnam (CMNP) was quantified by measuring biomass of trees, roots, and downed woody debris, and sediment organic C and overall depth. Results showed that above- and below-ground C stock ranged from 90.2 ± 15.8 to 115.2 ± 19.3 and from 629.0 ± 32.5 to 687.0 ± 29.2 MgC ha− 1, respectively. The combination of the above- and below-ground C stocks resulted in a high ecosystem C storage, which ranged from 719.2 ± 38.0 to 802.1 ± 12.3 MgC ha− 1, and slightly increased from fringe toward interior forest. The 13,400 ha of mangrove forests in the CMNP were estimated to store 10.3 (± 0.8) × 106 Mg of C, which is equivalent to 38.0 (± 3.0) × 106 Mg of CO2e. The present results suggest that the conservation of mangrove forest is needed to increase ecosystem C storage and to offset C emissions at the regional scale.