Their guidance and support inspired me throughout my studies at UC Berkeley. I am indebted to John K. C. Liu for his constant encouragement, incisive criticism, sense of humor, and faith in me. His and Shirley's Berkeley-Taiwan family life gave me insights for this volume. I also want to thank Richard Weismiller and Margarita Hill of the Department of Natural Resource Sciences and Landscape Architecture at the University of Maryland for their generous and continuous support of my research.