Dynamics of carbon, biomass, and structure in two Amazonian forests

Amazon forests are potentially globally significant sources or sinks for atmospheric carbon dioxide. In this study, we characterize the spatial trends in carbon storage and fluxes in both live and dead biomass (necromass) in two Amazonian forests, the Biological Dynamic of Forest Fragments Project (BDFFP), near Manaus, Amazonas, and the Tapajós National Forest (TNF) near Santarém, Pará. We assessed coarse woody debris (CWD) stocks, tree growth, mortality, and recruitment in ground-based plots distributed across the terra firme forest at both sites. Carbon dynamics were similar within each site, but differed significantly between the sites. The BDFFP and the TNF held comparable live biomass (167 ± 7.6 MgC·ha−1 versus 149 ± 6.0 MgC·ha−1, respectively), but stocks of CWD were 2.5 times larger at TNF (16.2 ± 1.5 MgC·ha−1 at BDFFP, versus 40.1 ± 3.9 MgC·ha−1 at TNF). A model of current forest dynamics suggests that the BDFFP was close to carbon balance, and its size class structure approximated a steady state. The TNF, by contrast, showed rapid carbon accrual to live biomass (3.24 ± 0.22 MgC·ha−1·a−1 in TNF, 2.59 ± 0.16 MgC·ha−1·a−1 in BDFFP), which was more than offset by losses from large stocks of CWD, as well as ongoing shifts of biomass among size classes. This pattern in the TNF suggests recovery from a significant disturbance. The net loss of carbon from the TNF will likely last 10–15 years after the initial disturbance (controlled by the rate of decay of coarse woody debris), followed by uptake of carbon as the forest size class structure and composition continue to shift. The frequency and longevity of forests showing such disequilibruim dynamics within the larger matrix of the Amazon remains an essential question to understanding Amazonian carbon balance.

Bibliographic Details

Main Authors:	75850 Hammond Pyle, Elizabeth Harvard University, Cambridge, Massachusetts, USA, 116073 Santoni, Gregory W. (autor/a) Harvard University, Cambridge, Massachusetts, USA, 98538 Nascimento, Henrique E.M. (autor/a) National Institute for Amazonian Research, Manaus, Brazil, 79372 Hutyra, Lucy R. (autor/a) Harvard University : University of Washington, 128756 Vieira, Simone Aparecida (autor/a) Universidade de Sao Paulo, Piracicaba, Brazil, 60510 Curran, Daniel J. (autor/a) Harvard University, Cambridge, Massachusetts, USA, 76112 Haren, Joost van (autor/a) University of Arizona, Tuscon, Arizona, USA, 115234 Saleska, Scott R. (autor/a) University of Arizona, Tuscon, Arizona, USA, 57417 Chow, V.Y. (autor/a) Harvard University, Cambridge, Massachusetts, USA, 54216 Carmago, Plinio B. (autor/a) Universidade de Sao Paulo, Piracicaba, Brazil, 85301 Laurance, William F. (autor/a) National Institute for Amazonian Research, Manaus, Brazil : 6Smithsonian Tropical Research Institute, Balboa, Panama, 131937 Wofsy, Steven C. (autor/a) Harvard University, Cambridge, Massachusetts, USA
Format:	Texto biblioteca
Language:	eng
Published:	Washington, D.C. American Geophysical Union 2008
Subjects:	BIOMASA, CARBONO, ALMACENAMIENTO, ALOMETRIA, MEDICION, MODELOS, CICLO DEL CARBONO, ECUACIONES ALOMETRICAS, AGRICULTURA, USO DE LA TIERRA, BIOMASS, CARBON, STORAGE, MEASUREMENT, MODELS, CARBON CYCLE, FORESTS, LAND USE,
Online Access:	https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2007JG000592
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