An inventory-based analysis of Canada's managed forest carbon dynamics, 1990 to 2008

Abstract

Canada's forests play an important role in the global carbon (C) cycle because of their large and dynamic C stocks. Detailed monitoring of C exchange between forests and the atmosphere and improved understanding of the processes that affect the net ecosystem exchange of C are needed to improve our understanding of the terrestrial C budget. We estimated the C budget of Canada's 2.3 × 106 km2 managed forests from 1990 to 2008 using an empirical modelling approach driven by detailed forestry datasets. We estimated that average net primary production (NPP) during this period was 809 ± 5 Tg C yr−1 (352 g C m−2 yr−1) and net ecosystem production (NEP) was 71 ± 9 Tg C yr−1 (31 g C m−2 yr−1). Harvesting transferred 45 ± 4 Tg C yr−1 out of the ecosystem and 45 ± 4 Tg C yr−1 within the ecosystem (from living biomass to dead organic matter pools). Fires released 23 ± 16 Tg C yr−1 directly to the atmosphere, and fires, insects and other natural disturbances transferred 52 ± 41 Tg C yr−1 from biomass to dead organic matter pools, from where C will gradually be released through decomposition. Net biome production (NBP) was only 2 ± 20 Tg C yr−1 (1 g C m−2 yr−1); the low C sequestration ratio (NBP/NPP=0.3%) is attributed to the high average age of Canada's managed forests and the impact of natural disturbances. Although net losses of ecosystem C occurred during several years due to large fires and widespread bark beetle outbreak, Canada's managed forests were a sink for atmospheric CO2 in all years, with an uptake of 50 ± 18 Tg C yr−1 [net ecosystem exchange (NEE) of CO2=−22 g C m−2 yr−1].

Differentiating moss from higher plants is critical in studying the carbon cycle of the boreal biome

“…For example, a study based on a nested inverse modelling system indicates Canada's sink to be large (0.34 ± 0.14 Pg C per year) 28 . However, ecosystem modelling and inventory-based analysis found Canada's forest to be a weak sink of 0.05-0.07 Pg C per year 11,25 . Regional carbon balance strongly depends on the accuracy of estimated GPP.…”

“…Model estimates of GPP for boreal North America varied between 2.6 and 11.6 Pg C per year, a larger range than that of temperate North America 8 . Estimates of net primary production (NPP) in Canada's boreal forest also showed a large uncertainty, varying from 140 to 444 g C m À 2 per year from three studies [9][10][11] .…”

Cradle-to-Gate Environmental Life Cycle Assessment of the Portfolio of an Innovative Forest Products Manufacturing Unit

“…It must be remembered that this balance does not integrate sequestration by the HWP. Moreover, the forest carbon emissions are primarily a result of natural disturbances such as fires or insect epidemics (Stinson et al 2011). For further information on the calculation method of forest carbon and for more details consult the report called "The Carbon Budget of the Canadian Forest Sector" (Kurz 1992).…”

The effect of climate on the net primary productivity (NPP) of Pinus koraiensis in the Changbai Mountains over the past 50 years

“…Three main approaches have been used in previous research to estimate forest NPP values: monitoring of sampling plots (Aragão et al 2009;Clark et al 2001;Fang et al 1996), model simulations (Euskirchen et al 2009;Stinson et al 2011;Tian et al 2010), and remote sensingbased estimation (Running et al 2004;Zhang et al 2009). Despite its high precision, the sampling plot approach is limited by the considerable workload and investigation period required.…”