This study examined the biomass data estimated from different allometric models and calculated the mean aboveground biomass, mean belowground biomass and root/shoot ratio values according to the forest types and age classes. These mean values and the forest inventories in 2009 were used to estimate the aboveground and total biomass carbon storage in different forest types (coniferous, deciduous and mixed forests). The aboveground and total biomass carbon storage for all forest types in Korea were 350.201 Tg C and 436.724 Tg C. Over the past 36 years, plantations by reforestation programs have accounted for more than 70% of the observed carbon storage. The carbon storage in Korean forest biomass was 436.724 Tg C, of which 175.154 Tg C for coniferous forests, 126.772 Tg C for deciduous forests and 134.518 Tg C for mixed forests, comprising approximately 1/20 of the total carbon storage of the East Asian countries. The total carbon storage for the whole forest sector in Korea was 1213.122 Tg C, of which 436.724 Tg C is stored in forest biomass if using the ratio of carbon storage in different pools examined from the United States. Such large carbon storage in Korean forests is due mainly to active plantations growth and management practices.