, Volume 7, Issue 5, pp 498–512

Production, Respiration, and Overall Carbon Balance in an Old-growth Pseudotsuga-Tsuga Forest Ecosystem


    • Department of Forest ScienceOregon State University
  • Ken Bible
    • College of Forest ResourcesUniversity of Washington
  • Michael G. Ryan
    • Rocky Mountain Research StationUSDA Forest Service
  • David C. Shaw
    • College of Forest ResourcesUniversity of Washington
  • H. Chen
    • Department of Forest ScienceOregon State University
  • Jeffrey Klopatek
    • Department of Plant BiologyArizona State University
  • Xia Li
    • Department of BiologyStanford University

DOI: 10.1007/s10021-004-0140-9

Cite this article as:
Harmon, M.E., Bible, K., Ryan, M.G. et al. Ecosystems (2004) 7: 498. doi:10.1007/s10021-004-0140-9


Ground-based measurements of stores, growth, mortality, litterfall, respiration, and decomposition were conducted in an old-growth forest at Wind River Experimental Forest, Washington, USA. These measurements were used to estimate gross primary production (GPP) and net primary production (NPP); autotrophic respiration (Ra) and heterotrophic (Rh) respiration; and net ecosystem production (NEP). Monte Carlo methods were used to calculate uncertainty (expressed as ± 2 standard deviations of 200–400 calculations). Live carbon (C) stores were 39,800 g C m−2 (34,800–44,800 g C m−2). The store of C in detritus and mineral soil was 22,092 g C m−2 (20,600–23,600 g C m−2), and the total C stores were 61,899 g C m−2 (56,600–67,700 g C m−2). Total NPP was 597 g C m−2 y−1 (453 to 741 g C m−2 y−1). Ra was 1309 g C m−2 y−1 (845–1773 g C m−2 y−1), indicating a GPP of 1906 g C m−2 y−1 (1444–2368 g C m−2 y−1). Rh, including the respiration of heart rots in tree boles, was 577 g C m−2 y−1 (479–675 g C m−2 y−1). Long-term NEP was estimated to be +20 g C m−2 y−1 (−116 to +156 g C m−2 y−1), indicating this stand might be a small sink. These estimates contrast with the larger sink estimated at the same site using eddy-flux methods. Several hypotheses to explain this discrepancy were explored, including (a) undetected biomass increases, (b) underestimates of NPP, (c) unmeasured losses, and (d) a temporal mismatch between the two sets of measurements. The last hypothesis appears the most likely.


autotrophic respiration carbon flux carbon stores decomposition gross primary production (GPP) heterotrophic respiration net ecosystem production (NEP) net primary production (NPP)

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© Springer-Verlag 2004