Mangrove forests are one of the most productive ecosystems. Their net primary production is an important index of evaluation of carbon cycling in these ecosystems, but our knowledge on the belowground production of mangrove forests is still limited. Thus, Objective this study is to examine and compare the NPP of mangrove forests focusing on fine roots. The study was conducted during January, 2019 and March, 2020 in two pure mangrove species communities of Rhizophoraceae: Kandelia obovata and Rhizophora stylosa in Manko wetland of Okinawa, Japan.
The total NPP of K. obovata ranged from 32.6 to 37.9 Mg ha-1 y-1 whereas for R. stylosa it ranged from 39.4 to 42.3 Mg ha-1 y-1 which declares R. stylosa as the more productive community between these two. Mean annual above ground biomass increment of R. stylosa (10.78 Mg ha-1 y-1) was greater than K. obovata (9.38 Mg ha-1 y-1) with major difference of producing stilt roots. Total above ground litters contributed 21.7-25.3% and 26.7-28.7% to total NPP for K. obovata and R. stylosa. Contributions of root production to the total NPP for K. obovata and R. stylosa ranged 43.3-51.2% and 29.8-34.7% whereas the contributions of total fine roots are 34.1-43.3% and 20.1-25.7% respectively.