Fire and biogeoscience plant ecology

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The four proposed research projects bring together ecological and physical (fire and geomorphology) processes in a manner that expands both disciplines. 1) The landscape development-plant tolerance project breaks new ground by using the Channel Hillslope Integrated Landscape Development Model to create a terrain with known climatic, hydrologic, and geomorphic processes and then putting plant communities of different species tolerances (corresponding to real communities) on this terrain's moisture gradients. The approach will help determine the role of different climates and geomorphology on species diversity. 2) Altitudinal treeline is usually narrowly defined by climate (cold); in this project we will examine the geomorphic processes (substrate instability and water shortage caused by slope processes) that also influence treeline. In a time of changing climate these other treeline processes may also change. 3) Wildfires remove the F and H organic layers of the soil by smoldering combustion and allow more successful tree regeneration. In this project we will determine the moisture budgets for the F and H layers-the most important process for smoldering combustion. We intend to create a small watershed (fifth-order stream) distributed model for the moisture budgets that can be used to predict F- and H-layer moisture. 4) Finally, we propose a spatially explicit model of tree mortality from surface fires. This project brings together the Wildlands Fire Dynamics Simulator and the tree mortality model which we have developed to predict tree death under a range of fire intensities. In a time of increased use of low intensity management burns, it is important to understand how heat transfer kills the trees so that the burns can be designed for the desired ecological effect.