Reforestation increases substantial carbon stock in plant biomass. However, reforestation’s effect on soilcarbon accumulation remains unclear, which hampers our understanding of carbon cycling in forestecosystems. The change patterns of soil carbon storage in four young plantations, Eucalyptus urophyllamonoculture (EU), Acacia crassicarpa monoculture (AC), Castanopsis hystrix monoculture (CH), a mixedplantation of 10 native tree species (MX), and a naturally recovered shrubland (NS), were compared atfifive stand ages during development in subtropical China. We observed that plant biomass was higherin plantations with fast-growing species (i.e. EU and AC) than with slow-growing species (i.e. CH andMX). However, no signifificant differences in soil carbon storage were observed among the four plantationswith the same stand ages. Meanwhile, there were no signifificant differences in soil carbon storage amongthe four plantations and NS. Furthermore, soil carbon storage exhibited a similar change pattern for thefour plantations and naturally recovered shrubland during the 10-year period of early vegetationdevelopment. Specififically, soil carbon storage decreased slightly and non-signifificantly during the fifirst4 years (from 23.84 Mg ha 1 to 20.79 Mg ha 1) and increased thereafter (35.85 Mg ha 1 in 10-year-oldplantations). These results suggest that plant biomass increment and soil carbon accumulation wereunsynchronized, and early reforestation had no signifificant effect on soil carbon accumulation. Weconclude that plantations did not accelerate carbon sequestration in soils at early developmental stagescompared with natural recovery and plant biomass may not be an appropriate index for evaluating soilcarbon sequestration in young plantation.