What Kind of Tree is That?

I found an awesome tree key online. Here: http://bioimages.vanderbilt.edu/tree-key/simple-leaf-trees.htm This one is only good for trees with "simple" leaves, meaning that they are not compound, or rather, that only one leaflet is on the leaf stem. Some trees like walnuts and ashes have many leaves extending from the leaf stem.

More than you wanted to know--unless you are into knowing about trees. =-]