Variability of snow water equivalent and snow energetics across a large catchment subject to Mountain Pine Beetle infestation and rapid salvage logging

This study examines the effect on stand and catchment scale snow processes due to widespread forest disturbance by the Mountain Pine Beetle (MPB; Dendroctonus ponderosae) infestation, for the 1570 km2 Baker Creek catchment in the B.C. interior where all healthy mature lodgepole pine (Pinus contorta) stands which dominated the catchment up until 2000 have since died or been salvage logged. Measurements in 2008 and 2009 indicate that this net canopy reduction has reduced peak snowpack and melt rate differences between remaining stands (including large clearcuts, younger regenerating stands and dead mature pine stands), relative to a healthy forest canopy with smaller clearcuts. The Distributed Hydrology Soil Vegetation Model (DHSVM) was calibrated and run at 200 m resolution across the catchment, and simulated snowmelt rates and snow-covered area compared relatively well to distributed satellite or ground-based measurements. Snowpack and ablation rates were 10–20% higher during the 2008 and 2009 winters than when running the model for the pre-MPB landscape in 2000 using the same input meteorological data, resulting in almost no difference in the snowcover period. A greater snowpack volume which enters the stream network faster inevitably has implications for streamflows, flood risks and water resources, and these are assessed during the next stage of this research project.