Canadian Forest Service Publications

National-scale estimates of forest root biomass carbon stocks and associated carbon fluxes in Canada. 2013. Smyth, C.E.; Kurz, W.A.; Neilson, E.T.; Stinson, G. Global Biogeochemical Cycles. 27(4): 1262-1273.

Year: 2013

Issued by: Pacific Forestry Centre

Catalog ID: 35433

Language: English

Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1002/2012GB004536

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Canada’s forests play an important role in the global carbon cycle through carbon (C) storage and C exchange with the atmosphere. While estimates of aboveground biomass have been improving, little is known about belowground C storage in root biomass. Here we estimated the contribution of roots to the C budget of Canada’s 2.3×106 km2 managed forests from 1990 to 2008 using the empirical modeling approach of the Carbon BudgetModel of the Canadian Forest Sector (CBM-CFS3) driven by detailed forestry data sets from the National Forest C Monitoring, Accounting and Reporting System. The estimated average net primary production (NPP) during this period was 809 Tg C yr1 (352 g C m2 yr1) with root growth and replacement of turnover contributing 39.8 % of NPP. Average heterotrophic respiration (Rh) was 738 Tg C yr1 (321 g C m2 yr1), which resulted in a net ecosystem production (NEP) value of 31 g Cm2 yr1(71TgCyr1), and on average only 8.7%of NPP remained in the system as NEP. Estimated average root C stocks were 2.38 Pg (1235 g C m2), mostly in coarse roots (≥ 5 mm diameter), and had an average root to shoot percentage (belowground to aboveground biomass) of 25.6%. Detailed monitoring of C exchange between forests and the atmosphere and an improved understanding of the belowground processes and their response to environmental changes are needed to improve our understanding of the terrestrial C budget.