Okay, I'll take a stab at it. The vertical tree/log on the left looks like black locust; the one on top running left to right (with the cut in it) looks like silver maple thats been down a while; the one under it could be from the same silver maple, but it's a bit hard to tell as it looks as though most of the bark is off. Of the 2 vertical logs on top; the one on the right kinda looks like black walnut bark and the one on the left... I won't venture to say as I can't see enough of it. So there's my best guess. Now let's see what the pros from Dover have to say about it.