TY - JOUR
T1 - Scale-dependence of aboveground carbon accumulation in secondary forests of Panama
T2 - A test of the intermediate peak hypothesis
AU - Mascaro, Joseph
AU - Asner, Gregory P.
AU - Dent, Daisy H.
AU - DeWalt, Saara J.
AU - Denslow, Julie S.
N1 - Funding Information:
We thank T. Kennedy-Bowdoin, J. Jacobson, D. Knapp, A. Balaji, and the rest of the Carnegie Airborne Observatory team for collecting and processing airborne LiDAR data, and two anonymous reviewers for comments that significantly improved this manuscript. This study was supported by the Gordon and Betty Moore Foundation , the John D. and Catherine T. MacArthur Foundation , the HSBC Climate Partnership , SENACYT ( COL10-052 to Daisy Dent) and the National Science Foundation ( DEB-92-08031 to Julie Denslow). The Carnegie Airborne Observatory is made possible by the Gordon and Betty Moore Foundation, the Grantham Foundation for the Protection of the Environment, W.M. Keck Foundation, and William Hearst III.
Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012/7/15
Y1 - 2012/7/15
N2 - Accumulation of aboveground carbon is one of the most important services provided by tropical secondary forests-a land-cover type that is increasing in importance globally. Carbon accumulates rapidly for the first 20. years of succession, but few studies have considered forests older than 20. years, and the available data do not yield a consistent pattern. Two alternative hypotheses have been proposed: (1) an asymptotic increase, with the highest carbon stocks occurring in the oldest stands, and (2) an intermediate peak, caused by roughly synchronous tree maturity (and thus high carbon stocks) after which time treefall gaps cause carbon stocks to regress. Here we revisited a well-studied tropical moist forest chronosequence in Barro Colorado Nature Monument, Central Panama, consisting of 35, 55, 85, and 115-year-old stands, as well as old-growth stands, to determine whether past evidence for the intermediate peak hypothesis was influenced by the spatial limitations of the field plots used to assess forest structure. We used airborne LiDAR (light detection and ranging) to measure carbon stocks at the scale of the original transects (0.16. ha), in surrounding forest of the same age (up to 20. ha), and at a landscape scale incorporating thousands of hectares not previously measured. We also compared forest structure as measured in three dimensions by LiDAR, considering vertical and horizontal variation in canopy organization, as well as the abundance of treefall gaps. Our results suggested a strong scale-dependence of aboveground carbon accumulation, supporting the intermediate peak hypothesis at the fine scale of the 0.16-ha transects, but an asymptotic model at the landscape scale incorporating thousands of hectares. Further analyses of forest structure suggest that both the limitations of small plots and intrinsic scaling of forest structure and carbon dynamics account for the scale-dependence of aboveground carbon accumulation in this secondary forest matrix.
AB - Accumulation of aboveground carbon is one of the most important services provided by tropical secondary forests-a land-cover type that is increasing in importance globally. Carbon accumulates rapidly for the first 20. years of succession, but few studies have considered forests older than 20. years, and the available data do not yield a consistent pattern. Two alternative hypotheses have been proposed: (1) an asymptotic increase, with the highest carbon stocks occurring in the oldest stands, and (2) an intermediate peak, caused by roughly synchronous tree maturity (and thus high carbon stocks) after which time treefall gaps cause carbon stocks to regress. Here we revisited a well-studied tropical moist forest chronosequence in Barro Colorado Nature Monument, Central Panama, consisting of 35, 55, 85, and 115-year-old stands, as well as old-growth stands, to determine whether past evidence for the intermediate peak hypothesis was influenced by the spatial limitations of the field plots used to assess forest structure. We used airborne LiDAR (light detection and ranging) to measure carbon stocks at the scale of the original transects (0.16. ha), in surrounding forest of the same age (up to 20. ha), and at a landscape scale incorporating thousands of hectares not previously measured. We also compared forest structure as measured in three dimensions by LiDAR, considering vertical and horizontal variation in canopy organization, as well as the abundance of treefall gaps. Our results suggested a strong scale-dependence of aboveground carbon accumulation, supporting the intermediate peak hypothesis at the fine scale of the 0.16-ha transects, but an asymptotic model at the landscape scale incorporating thousands of hectares. Further analyses of forest structure suggest that both the limitations of small plots and intrinsic scaling of forest structure and carbon dynamics account for the scale-dependence of aboveground carbon accumulation in this secondary forest matrix.
KW - Carbon storage
KW - Carnegie Airborne Observatory
KW - Forest structure
KW - LiDAR
KW - Treefall gaps
KW - Tropical secondary forests
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U2 - 10.1016/j.foreco.2012.03.032
DO - 10.1016/j.foreco.2012.03.032
M3 - Article
AN - SCOPUS:84859930159
SN - 0378-1127
VL - 276
SP - 62
EP - 70
JO - Forest Ecology and Management
JF - Forest Ecology and Management
ER -