Consulting my trusty Reader's Digest "Garden Problem Solver" I see that the only diagnosis they come up with for holes in cherry leaves is caterpillars. Slugs are unlikely in a tree, unless it's really small, and Japanese beetles you would spot easily, particularly early in the morning when they lie abed sluggishly amongst your leaves. However, there are all sorts of bugs that chew leaves. Flea beetles are frequent culprits on small plants. The question is, how ruthless do you want to be about getting rid of them? Gardens Alive has all kinds of organic bug killers and the book "Great Garden Formulas" has everything from hot pepper and garlic sprays to beer for slugs. Just remember that just because you find these ingredients in your refrigerator doesn't mean that they are benign to the helpful bugs that you want to keep around. Good luck! Gotta go, there's a thunderstorm about to burst overhead!