Canadian Forest Service Publications
Moving towards carbon neutrality: CO2 exchange of a black spruce forest ecosystem during the first 10 years of recovery after harvest. 2012. Coursolle, C., Giasson, M.-A., Margolis, H.A., Bernier, P.Y. Can. J. For. Res. 42: 1908–1918.
Issued by: Laurentian Forestry Centre
Catalog ID: 34297
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Disturbances control the landscape-level C dynamics of boreal forests, but post-disturbance C dynamics are usually poorly quantified. In the current study, we use 10 years of CO2 flux measurements at a boreal black spruce (Picea mariana (Mill.) B.S.P.) cutover in eastern Canada to estimate time to C neutrality, quantify the relative role of respiration versus photosynthesis during recovery, and determine the agreement between cumulated CO2 fluxes and plot-level changes in C content. The site was a net source of 139 g C·m-2·year-1 2 years post-harvest, dropped further to a source of 173 g C·m-2·year-1 4 years post-harvest, following a scarification treatment, and was nearly C neutral 10 years postharvest. Gross ecosystem productivity (GEP) increased by 50 g C·m-2·year-1 post-scarification, while ecosystem respiration (ER) increased by only 23 g C·m-2·year-1. The resulting net rate of increase of 27 g C·m-2·year-1 in net ecosystem productivity was driven by changes in increasing leaf area. In fact, vegetation regrowth had a much greater impact on annual fluxes than did interannual variability in climate. Biometric-based measurements of total C losses after harvest were in relatively good agreement with eddy-covariance-based estimates 8 years after the harvest.