Canadian Forest Service Publications

Component respiration, ecosystem respiration and net primary production of a mature black spruce forest in northern Quebec. 2010. Hermle, S.; Lavigne, M.B.; Bernier, P.Y.; Bergeron, O.; Paré, D. Tree Physiology 30: 527-540.

Year: 2010

Issued by: Atlantic Forestry Centre

Catalog ID: 31651

Language: English

Availability: Order paper copy (free)

Available from the Journal's Web site.
DOI: 10.1093/ treephys/ tpq 002

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We measured respiratory fluxes of carbon dioxide by aboveground tree components and soil respiration with chambers in 2005 and scaled up these measurements over space and time to estimate annual ecosystem respiration (_R_e) at a mature black spruce (Picea mariana (Mill.) B.S.P.) ecosystem in Quebec, Canada. We estimated periodic annual net primary production (NPP) for this ecosystem also. Re was estimated at 10.32 Mg C ha-1 year-1; heterotrophic respiration (_R_h) accounted for 52% of _R_e and autotrophic respiration (_R_a) accounted for the remainder. We estimated NPP at 3.02 Mg C ha-1 year-1, including production of bryophyte biomass but not including shrub NPP. we used these estimates of carbon fluxes to calculate a carbon use efficiency [CUE = Npp/(Npp + _R_a)] of 0.38. This estimate of CUE is similar to those reported for other boreal forest ecosystem and it is lower than the value frequently used in global studies. Based on the estimate of _R_h being greater than the estimate of NPP, the ecosystem was determined to emit approximately 2.38 MG C ha-1 year-1 to the atmosphere in 2005. Estimates of gross primary production (GPP = NPP + _R_a) and _R_e differed substantially from estimates of these fluxes derived from eddy covariance measurements during 2005 at this site. The ecological estimates of GPP and _R_e were substantially greater than those estimated for eddy covariance measurements. Applying a correction for lack of energy balance closure to eddy covariance estimates reduces differences with ecological estimates. We reviewed possible sources of systematic error in ecological estimates and discuss other possible explanations for these discrepancies.