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

Elizabeth Hammond Pyle, Gregory W. Santoni, Henrique E.M. Nascimento, Lucy R. Hutyra, Simone Vieira, Daniel J. Curran, Joost Van Haren, Scott R. Saleska, V. Y. Chow, Plinio B. Carmago, William F. Laurance, Steven C. Wofsy

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


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.

Original languageEnglish (US)
Article numberG00B08
JournalJournal of Geophysical Research: Biogeosciences
Issue number1
StatePublished - Mar 28 2009

ASJC Scopus subject areas

  • Geophysics
  • Oceanography
  • Forestry
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Palaeontology


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