Harris N L, Hagen S C, Saatchi S S, Pearson T R H, Woodall C W, Domke G M, Braswell B H, Walters B F, Brown S, Salas W, Fore A, Yu Y
Ecosystem Services Unit, Winrock International, 2121 Crystal Drive Suite 500, Arlington, VA 22202 USA.
Forests Program, World Resources Institute, 10 G Street NE Suite 800, Washington, DC 20002 USA.
Carbon Balance Manag. 2016 Nov 14;11(1):24. doi: 10.1186/s13021-016-0066-5. eCollection 2016 Dec.
Locating terrestrial sources and sinks of carbon (C) will be critical to developing strategies that contribute to the climate change mitigation goals of the Paris Agreement. Here we present spatially resolved estimates of net C change across United States (US) forest lands between 2006 and 2010 and attribute them to natural and anthropogenic processes.
Forests in the conterminous US sequestered -460 ± 48 Tg C year, while C losses from disturbance averaged 191 ± 10 Tg C year. Combining estimates of net C losses and gains results in net carbon change of -269 ± 49 Tg C year. New forests gained -8 ± 1 Tg C year, while deforestation resulted in losses of 6 ± 1 Tg C year. Forest land remaining forest land lost 185 ± 10 Tg C year to various disturbances; these losses were compensated by net carbon gains of -452 ± 48 Tg C year. C loss in the southern US was highest (105 ± 6 Tg C year) with the highest fractional contributions from harvest (92%) and wind (5%). C loss in the western US (44 ± 3 Tg C year) was due predominantly to harvest (66%), fire (15%), and insect damage (13%). The northern US had the lowest C loss (41 ± 2 Tg C year) with the most significant proportional contributions from harvest (86%), insect damage (9%), and conversion (3%). Taken together, these disturbances reduced the estimated potential C sink of US forests by 42%.
The framework presented here allows for the integration of ground and space observations to more fully inform US forest C policy and monitoring efforts.
确定陆地碳源和碳汇对于制定有助于实现《巴黎协定》气候变化缓解目标的战略至关重要。在此，我们展示了2006年至2010年美国森林土地净碳变化的空间分辨率估计值，并将其归因于自然和人为过程。
美国本土森林每年固碳-460±48太克，而干扰造成的碳损失平均每年为191±10太克。将净碳损失和净碳增益估计值相结合，得出每年净碳变化为-269±49太克。新森林每年固碳-8±1太克，而森林砍伐导致每年损失6±1太克。仍为林地的森林土地每年因各种干扰损失185±10太克碳；这些损失被每年-452±48太克的净碳增益所补偿。美国南部的碳损失最高（每年105±6太克），其中采伐（92%）和风灾（5%）占比最高。美国西部的碳损失（每年44±3太克）主要归因于采伐（66%）、火灾（15%）和虫害（13%）。美国北部的碳损失最低（每年41±2太克），其中采伐（86%）、虫害（9%）和土地转换（3%）的比例贡献最为显著。总体而言，这些干扰使美国森林估计的潜在碳汇减少了42%。
本文提出的框架允许整合地面和空间观测数据，以便更全面地为美国森林碳政策和监测工作提供信息。
