First Friday Climate Change Talks: Soil Moisture Modeling for Post-Fire Reforestation Support

Resource managers in the western U.S. are seeing increased tree recruitment failure, and as warming and drought accelerate fire activity, forest loss has outpaced our ability to reliably replant.  Relative to adults, tree seedlings are vulnerable to drought and heat stress. Forest regeneration thus represents a demographic bottleneck that will constrain the distribution of forests in the future. We developed a modeling framework and decision support tools for predicting post-fire conifer regeneration across the western US. Using high resolution weather and soils data coupled with ecohydrology and plant hydraulic models, we created 30-meter resolution maps of heat and moisture stress for the western U.S. and forecast these models into 2050 using data from the 6th coupled model intercomparison project.  These data are integrated into Regenmapper, a web-based tool for predicting post-fire conifer recruitment. Maps of potential land surface temperature where canopy cover is reduced or removed closely align with patterns of current forest cover and with empirical measurements of seedling mortality. Projected 2050 temperatures suggest potential for significant loss of low-elevation areas suitable for regeneration. Additional tools now in development will allow managers to explore the effects of vegetation manipulations on forest microclimates and water availability in order to better understand the implications of future harvest and wildfires on forest regeneration.