Coulston John W, Wear David N, Vose James M
United States Department of Agriculture Forest Service, 4700 Old Kingston Pike, Knoxville, TN 37919.
United States Department of Agriculture Forest Service, PO Box 8008 North Carolina State University Raleigh, NC 27695.
Sci Rep. 2015 Jan 23;5:8002. doi: 10.1038/srep08002.
Over the past century forest regrowth in Europe and North America expanded forest carbon (C) sinks and offset C emissions but future C accumulation is uncertain. Policy makers need insights into forest C dynamics as they anticipate emissions futures and goals. We used land use and forest inventory data to estimate how forest C dynamics have changed in the southeastern United States and attribute changes to land use, management, and disturbance causes. From 2007-2012, forests yielded a net sink of C because of net land use change (+6.48 Tg C yr(-1)) and net biomass accumulation (+75.4 Tg C yr(-1)). Forests disturbed by weather, insect/disease, and fire show dampened yet positive forest C changes (+1.56, +1.4, +5.48 Tg C yr(-1), respectively). Forest cutting caused net decreases in C (-76.7 Tg C yr(-1)) but was offset by forest growth (+143.77 Tg C yr(-1)). Forest growth rates depend on age or stage of development and projected C stock changes indicate a gradual slowing of carbon accumulation with anticipated forest aging (a reduction of 9.5% over the next five years). Additionally, small shifts in land use transitions consistent with economic futures resulted in a 40.6% decrease in C accumulation.
在过去的一个世纪里，欧洲和北美的森林再生扩大了森林碳汇并抵消了碳排放，但未来的碳积累情况尚不确定。政策制定者在预测排放前景和目标时需要深入了解森林碳动态。我们利用土地利用和森林清查数据来估算美国东南部森林碳动态的变化情况，并将这些变化归因于土地利用、管理和干扰因素。2007年至2012年期间，由于净土地利用变化（+6.48 Tg C yr⁻¹）和净生物量积累（+75.4 Tg C yr⁻¹），森林产生了净碳汇。受天气、病虫害和火灾干扰的森林显示出虽有减弱但仍为正向的森林碳变化（分别为+1.56、+1.4、+5.48 Tg C yr⁻¹）。森林砍伐导致碳净减少（-76.7 Tg C yr⁻¹），但被森林生长（+143.77 Tg C yr⁻¹）所抵消。森林生长速率取决于发育的年龄或阶段，预计的碳储量变化表明随着森林老化，碳积累将逐渐放缓（未来五年减少9.5%）。此外，与经济前景一致的土地利用转变的微小变化导致碳积累减少了40.6%。
