William (Bill) aims to understand both the external drivers (e.g., climate, biotic agents) and internal mechanisms (e.g., plant physiological processes) that determine when trees stop living, and start dying – to answer the question, “What kills trees?”. As an Assistant Professor of Plant Ecophysiology at the University of Florida, his research crosses the scales of single xylem conduits to globally distributed forests, and involves anatomical, physiological, and clima-tological approaches. He is particularly passionate about the fates of big, old trees – and their disproportionate contri-butions to healthy forest ecosystems.