In this research, a recent version of the Boreal Ecosystem Productivity Simulator (BEPS), called BEPS-TerrainLab, was adapted to northern peatlands and evaluated using observations made at the Mer Bleue bog located near Ottawa, Ontario, and the Sandhill fen located near Prince Albert, Saskatchewan. The code was extended and modified with a major focus on the adequate representation of northern peatlands' multi-layer canopy and the associated processes related to energy, water vapour and carbon dioxide fluxes through remotely-sensed leaf area index (LAI) maps. An important prerequisite for the successful mapping of LAI based on remote sensing imagery is the accurate measurement of LAI in the field with a standard technique such as the LAI-2000 plant canopy analyzer. As part of this research, a quick and reliable method to determine shrub LAI with the LAI-2000 instrument was developed. This method was used to collect a large number of LAI data at the Mer Bleue bog for the development of a new remote sensing-based methodology using multiple endmember spectral unmixing that allows for separate tree and shrub LAI mapping in ombrotrophic peatlands. A slight modification of this methodology allows for its application to minerotrophic peatlands and their surrounding landscapes. These LAI maps were used to explicitly represent the tree and shrub layers of the Mer Bleue bog and the tree and shrub/sedge layers of the Sandill fen within BEPS-TerrainLab. The adapted version of BEPS-TerrainLab was used to investigate the in fluence of mescoscale topography (Mer Bleue bog) and macro- and mesoscale topography (Sandhill fen) on wetness, evapotranspiration, and gross primary productivity during the snow-free period of 2004. This research suggests that future peatland ecosystem modelling efforts at regional and continental scales should include a peatland type-specific differentiation of macro- and mesoscale topographic effects on hydrology, to allow for a more realistic simulation of peatlands' soil water balance. This is an important prerequisite for the reduction of currently existing uncertainties in wetlands' contribution to North America's carbon dioxide and methane annual fluxes from an ecosystem modelling perspective.

In this research, a recent version of the Boreal Ecosystem Productivity Simulator (BEPS), called BEPS-TerrainLab, was adapted to northern peatlands and evaluated using observations made at the Mer Bleue bog located near Ottawa, Ontario, and the Sandhill fen located near Prince Albert, Saskatchewan. The code was extended and modified with a major focus on the adequate representation of northern peatlands' multi-layer canopy and the associated processes related to energy, water vapour and carbon dioxide fluxes through remotely-sensed leaf area index (LAI) maps. An important prerequisite for the successful mapping of LAI based on remote sensing imagery is the accurate measurement of LAI in the field with a standard technique such as the LAI-2000 plant canopy analyzer. As part of this research, a quick and reliable method to determine shrub LAI with the LAI-2000 instrument was developed. This method was used to collect a large number of LAI data at the Mer Bleue bog for the development of a new remote sensing-based methodology using multiple endmember spectral unmixing that allows for separate tree and shrub LAI mapping in ombrotrophic peatlands. A slight modification of this methodology allows for its application to minerotrophic peatlands and their surrounding landscapes. These LAI maps were used to explicitly represent the tree and shrub layers of the Mer Bleue bog and the tree and shrub/sedge layers of the Sandill fen within BEPS-TerrainLab. The adapted version of BEPS-TerrainLab was used to investigate the in fluence of mescoscale topography (Mer Bleue bog) and macro- and mesoscale topography (Sandhill fen) on wetness, evapotranspiration, and gross primary productivity during the snow-free period of 2004. This research suggests that future peatland ecosystem modelling efforts at regional and continental scales should include a peatland type-specific differentiation of macro- and mesoscale topographic effects on hydrology, to allow for a more realistic simulation of peatlands' soil water balance. This is an important prerequisite for the reduction of currently existing uncertainties in wetlands' contribution to North America's carbon dioxide and methane annual fluxes from an ecosystem modelling perspective.

The affect on leaf area index (LAI) and net ecosystem production (NEP) of the mountain pine beetle (Dendroctonus ponderosae) (MPB) outbreak in British Columbia affecting lodgepole pine (Pinus contorta var. latifolia) forests was examined from 1999 to 2008. The process-based carbon (C) cycle model – Boreal Ecosystem Productivity Simulator (BEPS) with remotely sensed LAI inputs was used to produce annual NEP maps, which were validated using field measurements. The annual NEP ranged from 2.43 to -8.03 MtC between 1999 and 2008, with sink to source conversion in 2000. The inter-annual variability for both LAI and NEP displayed initial decreases followed by a steadily increasing trend from 2006 to 2008 with NEP returning to near C neutrality in 2008 (-1.84 MtC). The resistance of LAI and NEP to MPB attack was attributed to ecosystem resilience in the form of secondary overstory growth and increased production of non-attacked host trees.

The affect on leaf area index (LAI) and net ecosystem production (NEP) of the mountain pine beetle (Dendroctonus ponderosae) (MPB) outbreak in British Columbia affecting lodgepole pine (Pinus contorta var. latifolia) forests was examined from 1999 to 2008. The process-based carbon (C) cycle model – Boreal Ecosystem Productivity Simulator (BEPS) with remotely sensed LAI inputs was used to produce annual NEP maps, which were validated using field measurements. The annual NEP ranged from 2.43 to -8.03 MtC between 1999 and 2008, with sink to source conversion in 2000. The inter-annual variability for both LAI and NEP displayed initial decreases followed by a steadily increasing trend from 2006 to 2008 with NEP returning to near C neutrality in 2008 (-1.84 MtC). The resistance of LAI and NEP to MPB attack was attributed to ecosystem resilience in the form of secondary overstory growth and increased production of non-attacked host trees.