Changes in forest biomass carbon storage in the South Carolina Piedmont between 1936 and 2005

With the widespread land-use conversion from abandoned farmlands to forests since 1930s, the Piedmont region of eastern United States has likely become an important carbon (C) sink. To quantify this potential C sink and understand its implication to the regional carbon budget and future forest management, we estimated the changes in forest biomass carbon storage in the South Carolina (SC) Piedmont between 1936 and 2005. Based on the nine periods of Forest Inventory and Analysis (FIA) data obtained for the Piedmont of South Carolina (18 counties, about 2.8 × 106 ha land area), we used allometric biomass regression equations, directly developed from recent FIA data, and biomass expansion factors to estimate the forest biomass carbon pool for each inventory year. Since 1936, the SC Piedmont forests have accumulated 81.84 Tg C due to forest expansion and regrowth, increasing from 57.36 Tg C in 1936 to 139.20 Tg C in 2005. Hardwood and softwood forests accounted for 74% (60.38 Tg C) and 26% (21.45 Tg C) of carbon accumulation during this period, respectively. The aboveground forest biomass carbon pool represented 80% or 65.17 Tg C of the total carbon accumulation while the belowground fine and coarse roots only accounted for 20% or 16.67 Tg C. From 1936 through 2005, forest carbon accumulated at a rate of 1.19 Tg C yr−1, offsetting 5.7% of CO2 emission (20.94 Tg C in 2003) of the entire state of South Carolina.