Forests are a key provider of ecosystems services throughout the globe. Understanding and ultimately predicting how forest are likely to respond to a changing climate is an active area of interest and research. While some model and empirical studies show increased in forest growth, particularly in temperature limited environments, there are also many studies that show declines in productivity and increased rates of forest mortality in response to greater or more frequent drought stress. Given the importance of water-limitation and drought stress as a control on how forests will respond to a changing climate, models that explicitly link forest productivity with hydrology are essential tools. I will provide an overview of RHESSys, a coupled model of ecosystem biogeochemical cycling and spatially distributed hydrology. RHESSys is an open-source tool that integrates state-of-the art science based understanding of forest structure and function with observational data from multiple sources, including point measures such as streamflow and carbon flux tower data and spatial data from remote sensing products. I will present a number of case studies that use this model to examine the geography of forest drought stress vulnerability. These case studies focus explicitly on eco-hydrologic interactions and demonstrate critical linkages among forest water use, carbon cycling, species-disturbance interactions, local micro-climate patterns and geomorphology. Use of the model provides an integrated systems-oriented perspective on forest drought stress and mortality and allows us to disentangle to relative importance of multiple controls on forest vulnerability. Our case studies also evaluate what management strategies may be most effective at mitigating forest drought stress at stand to watershed scales.
Tague, C. (2012): The geography of forest drought vulnerability: Integrating modeling and measurements (Invited). Fall Meeting, American Geophysical Union, December 2012. Abstract GC51F-02..