Stability of Soil Carbon Stocks Varies with Forest Composition in the Canadian Boreal Biome
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Changes in forest composition as a result of forest management, natural disturbances, and climate change may affect the accumulation of soil organic carbon (SOC). We examined the influence of common boreal tree species (trembling aspen, black spruce, and jack pine), either in pure stands or in conifer-broadleaf mixtures, on the amount, distribution, and quality of SOC in two regions of the Canadian boreal biome. Long-term laboratory incubations were used to assess SOC quality by quantifying proportions of fast carbon (C) (that is, proportion of total C released during the first 100 days of incubation) and active C (that is, modeled proportion of total C that can be potentially released). Total amounts of SOC did not differ between stand types, but the effects of stand type on SOC stocks and quality differed with soil depth. Among stand types, aspen stands had the greatest relative proportion of total SOC in deeper mineral layers and the lowest amount of active C in the organic layer. For these reasons, the SOC stock that developed under aspen was more stable than in the other stand types. Although black spruce stands allowed a greater accumulation of SOC in surface layers, these stocks, however, might become more vulnerable to extra losses if environmental conditions are to become more favorable to decomposition in the future. Our work highlights that boreal forest composition influences the stability of SOC stocks and how climate change could alter this large C pool.
Keywordsboreal forest tree species forest floor mineral soil organic matter quality carbon stability decomposition
This study was funded through the Natural Sciences and Engineering Research Council of Canada (SPG281886) and the Fonds Québécois de la Recherche sur la Nature et les Technologies. We acknowledge the support from Produits Forestiers Résolu, Tembec, BIOCAP Canada, the Ontario Ministry of Natural Resources, and the Canadian Forest Service. We are grateful to Luc St-Antoine, Éric Girard, Jessie Parent, Stephen Hart, and Alain Courcelles for their valuable assistance in the field and in the laboratory. We thank Michèle Bernier-Cardou for her statistical assistance and Yan Boulanger for comments on an earlier version of the manuscript.
- Binkley D. 1995. The influence of tree species on forest soils: processes and patterns. In: Mead DJ, Cornforth IS, Eds. Proceedings of the trees and soils workshop. Special Publication No. 10. Canterbury: Agronomy Society of New Zealand. pp 1–33.Google Scholar
- Canada’s NFI. 2010. Canada’s National Forest Inventory: monitoring the sustainability of Canada’s Forests. Ottawa, ON: Canadian Council of Forest Ministers. http://nfi.nfis.org.
- Environment Canada. 2010. Canadian climate normals or averages 1971–2000. Fredericton, NB: Environment Canada. http://www.climate.weatheroffice.ec.gc.ca/climate_normals/index_e.html.
- Finzi AC, Van Breemen N, Canham CD. 1998. Canopy tree–soil interactions within temperate forests: species effects on soil carbon and nitrogen. Ecol Appl 8:440–6.Google Scholar
- Gower ST, Hunter A, Campbell J, Vogel J, Veldhuis H, Harden J, Trumbore S, Norman JM, Kucharik CJ. 2000. Nutrient dynamics of the southern and northern BOREAS boreal forests. Ecoscience 7:481–90.Google Scholar
- Hendershot WH, Lalande H, Duquette M. 2007. Ion exchange and exchangeable cations. In: Carter MR, Gregorich EG, Eds. Soil sampling and methods of analysis. 2nd edn. Boca Raton, FL: CRC Press. p 197–206.Google Scholar
- IPCC. 2007. Climate change 2007: the physical science basis. Contribution of Working Group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge, UK: Cambridge University Press.Google Scholar
- Jenny H. 1994. Factors of soil formation. A system of quantitative pedology. New York, NY: Dover Publications.Google Scholar
- Kroetsch D, Wang C. 2007. Particle size distribution. In: Carter MR, Gregorich EG, Eds. Soil sampling and methods of analysis. 2nd edn. Boca Raton, FL: CRC Press. p 713–26.Google Scholar
- Maynard DG, Curran MP. 2007. Bulk density measurement in forest soils. In: Carter MR, Gregorich EG, Eds. Soil sampling and methods of analysis. 2nd edn. Boca Raton, FL: CRC Press. p 863–9.Google Scholar
- Preston CM, Trofymow JA, Canadian Intersite Decomposition Experiment Working Group. 2000. Variability in litter quality and its relationship to litter decay in Canadian forests. Can J Bot 78:1269–87.Google Scholar
- Soil Classification Working Group. 1998. The Canadian system of soil classification. 3rd edn. Ottawa, ON: Agriculture and Agri-Food Canada, Research Branch, Publication No. 1646.Google Scholar
- Wardle DA. 2002. Communities and ecosystems: linking the aboveground and belowground components. Princeton, NJ: Princeton University Press.Google Scholar