I agree that it looks like sweet gum. They grow like weeds around here. If you plan on slabbing it out, lay out some 1,000lb cargo straps about 24" apart when stacking and stickering for air drying. Cinch the stacks up tight, and periodically re-tighten them to minimize warping. Also, oversize the slab thickness some. Sweetgum has a bad tendency to warp, so strapping and giving yourself a little more thickness will increase your chances of getting useuable boards after flattening. My experience with milling some out using a chain saw mill was that it dulled the chains more quickly than white & red oak or walnut. Also a little tougher to hand plane, even though it is not one of the harder woods.
In the past, sweet gum was used by the furniture industry mainly as a secondary wood, for internal bracing, drawer frames, etc. Due to the variegated colors, every board is unique, so matching them for a wide panel assembly can be a challenge, especially for flat sawn lumber.