Here is a picture of a leaf I took several weeks ago. It shows what I had just learned is called "tar spot disease", which affects several kinds of maple trees. Through the leaf shape and the bark, I though tthe tree must be a silver maple, which seemed confirmed when I read that silver maples grow in wet areas. This tree is right next to the shore. Tar spot happens in wet areas, so this might have originated in the flood of last year, over wintered, and came out again this year.