For decades, ecologists assumed that a forest's downed, rotting logs were merely waste—the leftover debris of trees that had finished their useful lives. More recent fieldwork has overturned that view. A fallen log, it turns out, becomes a slow-release reservoir of moisture and nutrients, a nursery where seedlings take root in soil too poor to support them elsewhere, and a corridor along which insects, fungi, and small mammals travel. Far from marking an ending, the collapse of a great tree initiates a second, quieter phase of its contribution to the forest.