Two things. We do have a lot of wild mulberry around, and they do start out young with "strange" leaves, but the leaves change when they grow. Also we have some sweet gum a few miles away, however, I have compared in person leaves between these two - sweet gum and strange new tree, and not a match. So I though let me compare the mulberry with this new tree, but all leaves have already dropped from my wild mulberry and the ones on the ground are so crisp I could not un-wad them.
Many thanks for your help, and next spring I will get a comparison between mulberry and my new strange tree. Just one more comment, if this is a wild mulberry, it is on steroids!