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

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 Cm )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