Is there a better group for this question?

I have been trying to ID a tree that I have in my yard. Please help if you can.

* It is in the upper 3rd of Georgia east of Atlanta.
* 50 feet tall
* bark looks like Sweet Gum (but is not)
* leaves a
** untoothed simple (5 to 6 inches long)
** dark green in summer
** turn dark red in august (seems early)
** begin falling in late august (nearly bare by Nov)

* Does not drop limbs regularly
* seemingly uncommon as there are no others around

I have looked on lots of tree and leaf ID websites but have not found it yet.

Any ideas?

Thanks, TD