I've noticed stripped bark on several trees in my neighborhood in the middle of Joliet, Illinois. Some of the damage has been near the base of trees, so I suspected rabbits. Now I'm seeing bark stripped from the upper branches of lilacs and other trees - too high for deer and certainly too high for rabbits, unless we have rare, tree-climbing rabbits. There are no "chew marks", just stripped bark. What could be doing this - raccoons? opossums?

Helene, Haven't you heard of the famous rare tree climbing rabbits of Joliet? ;) If the bark is fresh and obviously not dead I would suspect it is squirrels. Generally we see it more in winter but certainly possible now. Usually a brief period where they do it. Try pepper sprays if it seems they are getting out of hand. If the bark is dead and dry, it could be just flaking away of damaged bark from old wounds. good luck,