Cacatch, if it is Sweet Gum, you should have no problem identifying the seed pods, as they are distinct. It is rare that they would have all fallen by now, as they cling on until early in the spring. See how the photo of the live tree is full of them. Every one I have checked is still holding the pods like that. Sweetgum will often times have cork like wings along the limbs and twigs, in Winged Elm the wings are tougher and more woody. If you do not find these pods it is unlikely that it is Sweetgum. If it is some type of Elm, you have found excellent bow wood. If it turns out to be Sweetgum, it will still make a serviceable bow if you make it longer and wider to handle the strain. I have made several from Sweetgum. Weak in compression, excellent in tension, I firmly believe it will make an excellent backing, and have some drying for just that endeavor.