Hydrologic Response and Recovery to Prescribed Fire and Vegetation Removal in a Small Rangeland Catchment

Abstract:

Prescribed fire can be used to return wild lands to their natural fire cycle, control invasive weeds, and deter wildfire, but there are knowledge gaps in the understanding of post-disturbance responses of vegetation and hydrology. The impact of a prescribed fire and subsequent aspen cutting on evapotranspiration (ET) and streamflow was assessed for a small mountainous watershed by capitalizing on the unique long-term knowledgebase developed for the Upper Sheep Creek Catchment, a 26-ha headwater catchment dominated by low sagebrush, mountain big sagebrush and aspen within the Reynolds Creek Experimental Watershed. The 2007 prescribed fire consumed 100% of the mountain big sagebrush area and approximately 21% of the low sagebrush area. The aspen, which were mostly untouched by the fire, were cut in the fall of 2008. Post-disturbance recovery of vegetation and evapotranspiration depended heavily on the loss of rooting depth. ET of mountain big sagebrush zone having deep-rooted shrubs that were destroyed by the fire took several years to recover, while that from the low sagebrush area with limited rooting depth recovered within two years of the fire. ET from the aspen trees, which can sprout from existing roots, recovered within two years. The prescribed fire and aspen cutting had no discernible impact on streamflow.