“zone. Gradually it severs the leaf from access to water, and the leaf dries and browns and in most cases falls off, either under its own weight or encouraged by wintery rains and winds. Within a few hours, the tree will have released substances to heal the scar the leaf has left, protecting itself from the evaporation of water, infection, or the invasion of parasites. Even as the leaves are falling, the buds of next year’s crop are already in place, waiting to erupt again in spring. Most trees produce their buds in high summer, and the autumn leaf fall reveals them, neat and expectant, protected from the cold by thick scales. We rarely notice them because we think”