DAVID R. DEWALLE is a Professor of Forest Hydrology with the School of Forest Resources at the Pennsylvania State University, and is also Director of the Pennsylvania Water Resources Research Center. He received his B.S. and M.S. degrees in forestry from the University of Missouri, and his Ph. D. in watershed management from Colorado State University. DeWalle has conducted research on the impacts of atmospheric deposition, urbanization, forest harvesting, and climate change on the hydrology and health of watersheds in Pennsylvania. He regularly teaches courses in watershed management, snow hydrology and forest microclimatology. In addition to holding numerous administrative positions at Penn State, such as Associate Director of the Institutes of the Environment and Forest Science Program Chair, DeWalle has been major advisor to over 50 M.S. and Ph.D. students since coming to Penn State in 1969. DeWalle has also been a visiting scientist with the University of Canterbury in New Zealand, University of East Anglia in England, and most recently the USDA, Agricultural Research Service in Las Cruces, New Mexico. He has served as President and is a fellow of the American Water Resources Association. ALBERT RANGO is a Research Hydrologist with the USDA Agricultural Research Service, Jornada Experimental Range, Las Cruces, New Mexico, USA. He received his B.S. and M.S. in meteorology from the Pennsylvania State University and his Ph.D. in watershed management from Colorado State University. Rango has conducted research on snow hydrology, hydrological modeling, effects of climate change, rangeland health and remediation, and applications of remote sensing. He has been President of the International Commission on Remote Sensing, the Western Snow Conference, and the American Water Resources Association. He is a fellow of the Western Snow Conference and the American Water Resources Association. He received the NASA Exceptional Service Medal (1974), the Agricultural Research Service Scientist of the Year Award (1999), and the Presidential Rank Award - Meritorious Senior Professional (2005). He has published over 330 professional papers.