Carbon changes in conterminous US forests associated with growth and majordisturbances: 1992–2001

Abstract

We estimated forest area and carbon changes in the conterminous United States using aremote sensing based land cover change map, forest fire data from the Monitoring Trendsin Burn Severity program, and forest growth and harvest data from the USDA ForestService, Forest Inventory and Analysis Program. Natural and human-associateddisturbances reduced the forest ecosystems’ carbon sink by 36% from 1992 to 2001,compared to that without disturbances in the 48 states. Among the three identifieddisturbances, forest-related land cover change contributed 33% of the total effect inreducing the forest carbon potential sink, while harvests and fires accounted for63% and 4% of the total effect, respectively. The nation’s forests sequestered1.6 ± 0.1 Pg (1015 petagram) carbonduring the period, or 0.18 Pg C yr − 1, with substantial regional variation. The southern region of the United States was a smallnet 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 relatedestimates of the current forest US greenhouse gas inventory, suggesting that furtherresearch using this approach is warranted.