A substantial increase in the number of forest plantations has been observed in the last two decades owing to a greater awareness on climate change and global initiative of REDD and REDD+ (Reducing Emissions from Deforestation and forest Degradation) programs. In light of this, biomass and total carbon stocks of woody plants were estimated in five study sites–four plantations and a natural forest at Puthupet, Tamil Nadu, India. The aboveground biomass in the study sites were 32.7, 38.1, 121.1, 143.2and 227.2 (Mg/ha) in Anacardium occidentale, Casuarina equisetifolia, Mangifera indica, Cocos nucifera and natural forest respectively. In the natural forest, Pterospermum canescens contributed to the greatest aboveground biomass (55.54 Mg/ha), whereas the least was from Diospyros ferrea (1.07 Mg/ha). The maximum carbon stock was reported from the natural forest site (131.8 Mg/ha) while the minimum was from Anacardium occidentale plantation (19.5 Mg/ha). A significant positive relationship was observed between basal area with biomass and total carbon. The low values of biomass and carbon stocks in plantations maybe due to less stand age structure. Our results suggest that besides the natural forests, plantations also have great potential for carbon sequestration in the coastal areas and suggest developing more plantations and retaining it for a longer period of time will be helpful in reducing the atmospheric carbon dioxide concentrations.