title: Increasing carbon storage in intact African tropical forests.
abstract: The response of terrestrial vegetation to a globally changing environment is central to predictions of future levels of atmospheric carbon dioxide. The role of tropical forests is critical because they are carbon-dense and highly productive. Inventory plots across Amazonia show that old-growth forests have increased in carbon storage over recent decades, but the response of one-third of the world's tropical forests in Africa is largely unknown owing to an absence of spatially extensive observation networks. Here we report data from a ten-country network of long-term monitoring plots in African tropical forests. We find that across 79 plots (163 ha) above-ground carbon storage in live trees increased by 0.63 Mg C ha(-1) yr(-1) between 1968 and 2007 (95% confidence interval (CI), 0.22-0.94; mean interval, 1987-96). Extrapolation to unmeasured forest components (live roots, small trees, necromass) and scaling to the continent implies a total increase in carbon storage in African tropical forest trees of 0.34 Pg C yr(-1) (CI, 0.15-0.43). These reported changes in carbon storage are similar to those reported for Amazonian forests per unit area, providing evidence that increasing carbon storage in old-growth forests is a pan-tropical phenomenon. Indeed, combining all standardized inventory data from this study and from tropical America and Asia together yields a comparable figure of 0.49 Mg C ha(-1) yr(-1) (n = 156; 562 ha; CI, 0.29-0.66; mean interval, 1987-97). This indicates a carbon sink of 1.3 Pg C yr(-1) (CI, 0.8-1.6) across all tropical forests during recent decades. Taxon-specific analyses of African inventory and other data suggest that widespread changes in resource availability, such as increasing atmospheric carbon dioxide concentrations, may be the cause of the increase in carbon stocks, as some theory and models predict.
authors.affiliation: Earth and Biosphere Institute, School of Geography, University of Leeds, Leeds LS2 9JT, UK. s.l.lewis@leeds.ac.uk
authors.forename: Simon L
authors.initials: SL
authors.lastname: Lewis
authors.forename: Gabriela
authors.initials: G
authors.lastname: Lopez-Gonzalez
authors.forename: Bonaventure
authors.initials: B
authors.lastname: Sonké
authors.forename: Kofi
authors.initials: K
authors.lastname: Affum-Baffoe
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Baker
authors.forename: Lucas O
authors.initials: LO
authors.lastname: Ojo
authors.forename: Oliver L
authors.initials: OL
authors.lastname: Phillips
authors.forename: Jan M
authors.initials: JM
authors.lastname: Reitsma
authors.forename: Lee
authors.initials: L
authors.lastname: White
authors.forename: James A
authors.initials: JA
authors.lastname: Comiskey
authors.forename: Marie-Noël
authors.initials: MN
authors.lastname: Djuikouo K
authors.forename: Corneille E N
authors.initials: CE
authors.lastname: Ewango
authors.forename: Ted R
authors.initials: TR
authors.lastname: Feldpausch
authors.forename: Alan C
authors.initials: AC
authors.lastname: Hamilton
authors.forename: Manuel
authors.initials: M
authors.lastname: Gloor
authors.forename: Terese
authors.initials: T
authors.lastname: Hart
authors.forename: Annette
authors.initials: A
authors.lastname: Hladik
authors.forename: Jon
authors.initials: J
authors.lastname: Lloyd
authors.forename: Jon C
authors.initials: JC
authors.lastname: Lovett
authors.forename: Jean-Remy
authors.initials: JR
authors.lastname: Makana
authors.forename: Yadvinder
authors.initials: Y
authors.lastname: Malhi
authors.forename: Frank M
authors.initials: FM
authors.lastname: Mbago
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Ndangalasi
authors.forename: Julie
authors.initials: J
authors.lastname: Peacock
authors.forename: Kelvin S-H
authors.initials: KS
authors.lastname: Peh
authors.forename: Douglas
authors.initials: D
authors.lastname: Sheil
authors.forename: Terry
authors.initials: T
authors.lastname: Sunderland
authors.forename: Michael D
authors.initials: MD
authors.lastname: Swaine
authors.forename: James
authors.initials: J
authors.lastname: Taplin
authors.forename: David
authors.initials: D
authors.lastname: Taylor
authors.forename: Sean C
authors.initials: SC
authors.lastname: Thomas
authors.forename: Raymond
authors.initials: R
authors.lastname: Votere
authors.forename: Hannsjörg
authors.initials: H
authors.lastname: Wöll
mesh_terms: D000349:Africa; D001272:Atmosphere / Q000737:chemistry; D018533:Biomass; D002244:Carbon / Q000032:analysis / Q000378:metabolism*; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism; D008954:Models, Biological; D014197:Trees / Q000033:anatomy & histology / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D014329:Tropical Climate; D055814:Wilderness; D014934:Wood / Q000032:analysis / Q000737:chemistry
chemical_list: D002245:Carbon Dioxide; D002244:Carbon