Sickly Japanese Maple has lichen?? Here are the photos of the moldy mossy poor Japanese Maple in front of my son's house in Michigan, USA. What ever can be done to get rid of this crud before it kills the beautiful tree? He would spray something on if we had a clue. I have no idea. Friend who is a master gardener says she thinks this is tree lichen. Is it a sign the tree is sick or dying? Is it harmful as well as ugly? How do you get rid of it?