Reforestation can sequester two petagrams of carbon in US topsoils in a century
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Proceedings of the National Academy of Sciences
Soils are Earth’s largest terrestrial carbon (C) pool, and their responsiveness to land use and management make them appealing targets for strategies to enhance C sequestration. Numerous studies have identified practices that increase soil C, but their inferences are often based on limited data extrapolated over large areas. Here, we combine 15,000 observations from two national-level databases with remote sensing information to address the impacts of reforestation on the sequestration of C in topsoils (uppermost mineral soil horizons). We quantify C stocks in cultivated, reforesting, and natural forest topsoils; rates of C accumulation in reforesting topsoils; and their contribution to the US forest C sink. Our results indicate that reforestation increases topsoil C storage, and that reforesting lands, currently occupying >500,000 km2 in the United States, will sequester a cumulative 1.3–2.1 Pg C within a century (13–21 Tg C·y−1). Annually, these C gains constitute 10% of the US forest sector C sink and offset 1% of all US greenhouse gas emissions.
Keywordsland use; greenhouse gas; mitigation; soil carbon; management
Nave, Lucas E.; Domke, Grant M.; Hofmeister, Kathryn L.; Mishra, Umakant; Perry, Charles H.; Walters, Brian F.; Swanston, Christopher W. 2018. Reforestation can sequester two petagrams of carbon in US topsoils in a century. Proceedings of the National Academy of Sciences. 292: 201719685-. https://doi.org/10.1073/pnas.1719685115.