UW Aquatic & Fishery Sciences Quantitative Seminar

Caitlin Littlefield

PhD Student, UW, SEFS

Patterns of post-fire forest recovery in complex topography

Abstract

Understanding the drivers and spatial variability of post-fire forest recovery is critical to predicting both how ecosystems may respond to climate change and where management actions may best influence ecosystem resilience. Here, I will contribute to that understanding with initial results from a field-based assessment of how terrain-driven climate variability influences patterns of forest recovery. I inventoried juvenile conifers in areas that experienced complete overstory mortality in the 2006 Tripod Complex fire, which burned in the lower-elevation and montane mixed conifer forests of Washington's Okanogan-Wenatchee National Forest. I stratified sites by several topographic indices -- topographic wetness index, heat load index, and elevation -- to capture a range of emergent climatic conditions (or "topoclimates"). Using these indices, a remotely-sensed topoclimate dataset, weather station data, and in situ relative humidity and temperature measurements, I will characterize how the spatial pattern of juvenile trees that has emerged 10-years since the fire -- including species composition, density, year of establishment, interannual growth -- reflects terrain-driven climate variability. My results will highlight spatial configurations with relatively less robust juvenile recruitment where management that promotes recovery and reduces vulnerability to future disturbances may be desirable. On the other hand, spatial configurations with more robust juvenile recruitment -- especially of higher-elevation species -- may suggest the potential for climate microrefugia that may be considered for protection. With this research, I seek to inform the growing efforts to use topography as an efficient guide for resilience-enhancing management and conservation prioritizations across large landscapes and under climate change.