Attribution of net carbon change by disturbance type across forest lands of the conterminous United States

N L Harris; S C Hagen; S S Saatchi; T R H Pearson; C W Woodall; G M Domke; B H Braswell; B F Walters; S Brown; W Salas; A Fore; Y Yu

doi:10.1186/s13021-016-0066-5

Attribution of net carbon change by disturbance type across forest lands of the conterminous United States

Carbon Balance Manag. 2016 Nov 14;11(1):24. doi: 10.1186/s13021-016-0066-5. eCollection 2016 Dec.

Authors

N L Harris^#^{1

2}, S C Hagen^#³, S S Saatchi⁴, T R H Pearson¹, C W Woodall⁵, G M Domke⁵, B H Braswell³, B F Walters⁵, S Brown¹, W Salas³, A Fore⁴, Y Yu⁴

Affiliations

¹ Ecosystem Services Unit, Winrock International, 2121 Crystal Drive Suite 500, Arlington, VA 22202 USA.
² Forests Program, World Resources Institute, 10 G Street NE Suite 800, Washington, DC 20002 USA.
³ Applied Geosolutions, 55 Main Street Suite 125, Newmarket, NH 03857 USA.
⁴ NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA.
⁵ USDA Forest Service, Northern Research Station, Saint Paul, MN 55108 USA.

^# Contributed equally.

Abstract

Background: 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.

Results: Forests in the conterminous US sequestered -460 ± 48 Tg C year^-1, while C losses from disturbance averaged 191 ± 10 Tg C year^-1. Combining estimates of net C losses and gains results in net carbon change of -269 ± 49 Tg C year^-1. New forests gained -8 ± 1 Tg C year^-1, while deforestation resulted in losses of 6 ± 1 Tg C year^-1. Forest land remaining forest land lost 185 ± 10 Tg C year^-1 to various disturbances; these losses were compensated by net carbon gains of -452 ± 48 Tg C year^-1. C loss in the southern US was highest (105 ± 6 Tg C year^-1) with the highest fractional contributions from harvest (92%) and wind (5%). C loss in the western US (44 ± 3 Tg C year^-1) 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^-1) 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%.

Conclusion: The framework presented here allows for the integration of ground and space observations to more fully inform US forest C policy and monitoring efforts.

Keywords: Climate change; Disturbance; Drought; FIA; Fire; Forests; Greenhouse gas; Harvest; Insects; Land use; UNFCCC.