McLaughlin, J. W. 2004. Ontario Forest Research Institute
This report reviews the literature on C cycling in northern wetlands, with a focus on peatlands, in the context of C assessment in boreal peatlands of Ontario, Canada. It summarizes the current state-of-knowledge in peatland C dynamics, identifies critical research gaps, and presents research that is currently being conducted to improve the ability to assess C in Ontario's peatlands. This report comprises 5 major sections: (1) Introduction; (2) Extent and types of wetlands; (3) C cycling in boreal peatlands; (4) Scaling peatland C; and (5) Summary and recommendations. The first section introduces the topic of peatland C cycling and the importance of vegetation and hydrologic interactions in its regulation. It also presents the components of peatland C budgets, emphasizing the lack of information about a number of these components. The second section lists the uncertainties in global estimates of wetland extent and describes the boreal wetland regions and wetland types in Canada including peatlands in Ontario based on peatland inventories for northeastern and northwestern Ontario. The third section is divided into 7 subsections: (1) Peatland net primary production and litter decomposition; (2) Peat accumulation and C sequestration; (3) C storage in Ontario's boreal peatlands; (4) C cycling dynamics; (5) Methane; (6) Carbon dioxide; and (7) Climate change and peatland C cycling. The fourth section discusses the different approaches used to scale peatland C to landscape, regional and global levels, focusing on carbon dioxide and methane. Bottom-up techniques, that is, the emission factor approach and modelling, are presented. The final section reiterates the land area, estimated C storage, and methane efflux of Ontario's boreal peatland resource. It also summarizes the knowledge gaps remaining before accurate assessments of peatland C budgets are possible.
