Changing Cold Regions Network

In the southern fringe of discontinuous permafrost, permafrost is relatively warm and thin, and as a consequence, its thaw often leads to its disappearance. In the lower Liard River valley, south of Fort Simpson, NWT, the area occupied by permafrost has decrease from approximately 70% to 40%. In recent years the frequency and severity of forest fires has also increased. However the impact of forest fires on the rate and pattern of ground thaw, including permafrost thaw is poorly understood. Increasing our understanding of these fire-induced thaw processes will improve our ability to develop predictive models and improved predictive capacity as to the impacts of fires.

The main purpose of this research is to model the surface-energy-balance after a partial forest fire on a peat plateau at Scotty Creek (61°18’5.15²N; 121°17’58.87²W) in the Lower Liard River Basin, 50km south of Fort Simpson, Northwest Territory, Canada. Previous studies on energy modelling and forest fires show increasing permafrost thaw due to; increase incoming solar radiation from the loss of the canopy, and decrease in albedo from the blackened surface. However, in the case in a partial forest fire, where the forest has not been completely removed, the accuracy of models to predict the impact on ground thaw regimes is not known.