The aboveground dynamics, biomass, productivity and carbon storage rate of major mangrove communities on Pohnpei Island, Federated States of Micronesia, were estimated using census data obtained from two 1-hectare permanent plots during about two decades. The aboveground biomass increased from 526 t ha^ in 1994 to 572 t ha^ in 2010 for the plot situated in a coral reef-type habitat, referred to as PC1, and from 637 t ha^ in 1994 to 744 t ha^ in 2011 for the plot situated in an estuary-type habitat, referred to as PE1. Both were higher than any other estimates for mangrove forests throughout the world, though the tree density decreased from 1,558 trees ha^ to 1,074 trees ha^ in PC1 and from 651 trees ha^ to 473 trees ha^ in PE1. The ratio of trees cut by local residents to all deceased trees was higher in PC1 (35%) than PE1 (15%) because of different accessibility. The potential rates of aboveground carbon storage were estimated at 1.66 t C ha^ yr^ for PC1 and 2.79 t C ha^ yr^ for PE1. The difference was considered to have resulted from different stages of succession and site environments, such as soil water EC, ground elevation and frequency of submergence by tides