The bark is falling off my tree — what should I do?

Sheets, plates, or long strips of bark on the ground or hanging loose from the trunk. Under them, smooth pale wood with no green layer when you scratch it with a thumbnail. Often a vertical bare strip running up one side, sometimes with a black, gray, or tan crust on the exposed wood. The normal version looks different: sycamore, river birch, shagbark hickory, and silver maple shed thin curls or plates evenly all over, the wood beneath looks fresh, and the canopy is full. Bark does not fall off living wood. Wherever it sloughs, the cambium underneath died some time ago and that section of trunk stopped moving water and sugar — the shedding is the aftermath, not the event. The number that decides everything is how much of the trunk's circumference is involved. A strip is a wound the tree grows around. A band all the way around is a girdle, and everything above it is finished whether it looks green today or not.