Canadian Forest Service Publications

Late-summer carbon fluxes from Canadian forests and peatlands along an east-west continental transect. 2006. Coursolle, C.; Margolis, H.A.; Barr, A.G.; Black, T.A.; Amiro, B.D.; McCaughey, J.H.; Flanagan, L.B.; Lafleur, P.M.; Roulet, N.T.; Bourque, C.P-A.; Arain, M.A.; Wofsy, S.C.; Dunn, A.; Morgenstern, K.; Orchansky, A.L.; Bernier, P.Y.; Chen, J.M.; Kidston, J.; Saigusa, N.; Hedstrom, N. Can. J. For. Res. 36(3): 783-800.

Year: 2006

Available from: Laurentian Forestry Centre

Catalog ID: 26613

Language: English

CFS Availability: PDF (request by e-mail)

Abstract

Net ecosystem productivity (NEP) during August 2003 was measured by using eddy covariance above 17 forest and 3 peatland sites along an east-west continental-scale transect in Canada. Measured sites included recently disturbed stands, young forest stands, intermediate-aged conifer stands, mature deciduous stands, mature conifer stands, fens, and an open shrub bog. Diurnal courses of NEP showed strong coherence within the different ecosystem categories. Recently disturbed sites showed the weskest diurnal cycle; and intermediate-aged conifers, the strongest. The western treed fen had a more pronounced diurnal pattern than the eastern shrub bog or the Saskatchewan patterned fen. All but three ring were clearly afternoon C sinks. Ecosystem respiration was highest for the young fire sites. The intermediate-aged conifer sites had the highest maximum NEP (NEPMAX) and gross ecosystem productivity (GEPMAX), attaining rates that would be consistent with the presence of a strong terrestrial C sink in regions where these types of forest are common. These results support the idea that large-scale C cycle modeling activities would benefit from information on the age-class distribution and disturbance types within larger grid cells. Light use efficiency followed a pattern similar to that of NEPMAX and GEPMAX. Four of the five recently disturbed sites and all three of the peatland sites had low water use efficiencies.

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