CARBON ACCUMULATION POTENTIALS OF POST-SMCRA COAL-MINED LANDS

摘要

Many coal-surface mines reclaimed under SMCRA in eastern US were not restored to forest vegetation and are not currently in a managed use. Reforestation of these lands could provide benefits including timber production, watershed protection, and carbon (C) sequestration. Our objectives were to determine the suitability of eastern US coal-mined lands' soil properties for reforestation and to estimate the cumulative potential of these lands to accumulate C through reforestation. Databases of coal mining permits issued under SMCRA were obtained for KY, OH, VA, and WV, and 20 bond-released permits were selected in each state using an area-weighted randomization procedure. Access permissions were obtained for 25 sites (6 each in OH, KY, and VA, and 7 in WV), each of which was sampled at up to 10 randomly selected points. At each sampling point, soil physical properties were determined for the top 30 cm, and soil chemical properties were determined for surface (0-10 cm) and subsurface (10-30 cm) soil layers. Measured soil properties were used to estimate forest site productivity (SI50) using two methods, and each site's potential to accumulate C was estimated as a function of SI50 based on relationships derived from soil property and C accumulations on pre-SMCRA surface mines. Assuming these sites to be representative of eastern US mined lands, and that 50 percent of eastern US post-SMCRA mined lands could be available for reforestation under sufficient financial incentives, post-SMCRA mined lands reforested with pine species have the potential to accumulate on the order of 1.6 Tg C yr~(-1) over a 30 year rotation, equivalent to about 0.2 percent of projected US coal-combustion C emissions.