Why do ginkgo trees drop all their leaves at once? And what does UNH’s iconic James Hall ginkgo tell us about how frost is coming later in the fall? Serita Frey, a professor of natural resources, explains the science of why leaves fall, and shares the quirky 50-year-old student tradition that’s given her new insights into our changing seasons. UNH Research UNH College of Life Sciences and Agriculture | University of New Hampshire