Vegetation structure and dynamics exert a profound control on the hydrological cycle through their influence on evapotranspiration (the dominant hydrological flux) and on sublimation, which controls the amount of water available as snowmelt runoff. Nowhere is this more significant than in alpine headwater catchments. Headwater landscape assemblages have important ecohydrological interactions with basin vegetation and physiography, and the geometric complexity of these systems results in large variability in water cycling over small scales as slope, aspect and elevation control thermal and hydrological regimes. Across this landscape, there is a gradient of vegetation from largely coniferous forests in the south that can be heavily managed, to shrub and tundra vegetation with elevation and latitude. The potential for managing snow in forests for water supply objectives has been a long term goal in Alberta, and with recent advances in Alberta mountain forest disturbance hydrology there is potential to model the impacts of precision management of forested watersheds for multiple uses. Further, associated with climate warming, there are widespread shifts in vegetation type, most notably treeline advance and the encroachment of shrubs at high elevation. The objective of studying vegetation change is to improve our capacity to predict changes in water yield from headwater basins by understanding and numerically representing the role of vegetation on water storage and cycling in alpine watersheds.