Increasing carbon storage in intact African tropical forests.
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.
Lewis
Simon L
SL
Earth and Biosphere Institute, School of Geography, University of Leeds, Leeds LS2 9JT, UK. s.l.lewis@leeds.ac.uk
Lopez-Gonzalez
Gabriela
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Sonké
Bonaventure
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Affum-Baffoe
Kofi
K
Baker
Timothy R
TR
Ojo
Lucas O
LO
Phillips
Oliver L
OL
Reitsma
Jan M
JM
White
Lee
L
Comiskey
James A
JA
Djuikouo K
Marie-Noël
MN
Ewango
Corneille E N
CE
Feldpausch
Ted R
TR
Hamilton
Alan C
AC
Gloor
Manuel
M
Hart
Terese
T
Hladik
Annette
A
Lloyd
Jon
J
Lovett
Jon C
JC
Makana
Jean-Remy
JR
Malhi
Yadvinder
Y
Mbago
Frank M
FM
Ndangalasi
Henry J
HJ
Peacock
Julie
J
Peh
Kelvin S-H
KS
Sheil
Douglas
D
Sunderland
Terry
T
Swaine
Michael D
MD
Taplin
James
J
Taylor
David
D
Thomas
Sean C
SC
Votere
Raymond
R
Wöll
Hannsjörg
H
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
D002245:Carbon Dioxide; D002244:Carbon