Carbon cycling in a loblolly pine forest: implications for the missing carbon sink and for the concept of soil
During the 34 yr of forest regrowth, ecosystem C increased by 175.5 Mg/ha, averaging 5.16 Mg ha-1 yr-1. Nearly all (>98%) of this C accumulated in plant biomass and forest floor, with <2% of newly accumulated C stored in the surficial 0.6 m of mineral soil. These relatively low rates of C reaccumulation in surficial layers were attributed to rapid turnover of C in coarse surface soils. From the perspective of the C cycle the dichotomy of solum and parent material is artificial. In the loblolly pine system, for example, it is clear that the entire 6-m profile of O to C horizons is subjected to biogeochemical processes of a distinctly pedogenic nature. Definitions of soil and pedogenesis need to fully incorporate C horizons as part of the soil profile. -from Authors