摘要：We estimated forest area and carbon changes in the conterminous United States using a
remote sensing based land cover change map, forest fire data from the Monitoring Trends
in Burn Severity program, and forest growth and harvest data from the USDA Forest
Service, Forest Inventory and Analysis Program. Natural and human-associated
disturbances reduced the forest ecosystems' carbon sink by 36% from 1992 to 2001,
compared to that without disturbances in the 48 states. Among the three identified
disturbances, forest-related land cover change contributed 33% of the total effect in
reducing the forest carbon potential sink, while harvests and fires accounted for
63% and 4% of the total effect, respectively. The nation's forests sequestered
1.6 ± 0.1 Pg (1015 petagram) carbon
during the period, or 0.18 Pg C yr − 1, with substantial regional variation. The southern region of the United States was a small
net carbon source whereas the greater Pacific Northwest region was a strong net sink.
Results of the approach fit reasonably well at an aggregate level with other related
estimates of the current forest US greenhouse gas inventory, suggesting that further
research using this approach is warranted.
