Background: Prescribed burning is a common practice of site preparation before afforestation in subtropicalforests. However, the effects of prescribed burning on carbon (C) dynamics of an ecosystem are poorly understood.Therefore, a Eucalyptus urophylla plantation (EU) and a naturally recovered shrubland (NS), each treated withprescribed burning and no burning were examined in subtropical China.

Methods: Biomass of trees and shrubs in the 1st, 3nd, 4th, and 6th year after treatments were estimated byquadrat survey and allometric equations. Biomass of herbs and forest floors were estimated by harvest method.Plant biomass C storage was calculated by plant biomass multiplying by its C concentration. Soil organic C (SOC)storage in the 6th year after treatments was estimated by SOC concentration multiplying by soil bulk density andsoil volumes.

Results: Tree biomass C storage was significantly higher in the burned EU (BEU) than in the unburned EU (UEU) inthe 1st year after treatments, yet the difference decreased over time. Conversely, tree biomass C storage was lowerin the burned NS (BNS) than in the unburned NS (UNS), although the difference was not significant. However, inthe 6th year after treatments, the total plant biomass C storage was 14.56% higher in the BEU than that in the UEU,and 59.93% higher in the BNS than that in the UNS, respectively, although the significant difference was only foundbetween UNS and BNS. In addition, neither SOC storage at 0–20 cm nor ecosystem C storage in either the EU or NSwas significantly affected by prescribed burning.

Conclusions: Prescribed burning has little impact on overall C storage of forest ecosystems, we consider thatprescribed burning may be an option for forest site preparation regarding plant biomass C accumulation.