It is hard to tell from the pictures, but it looks like the branches may be growing opposite from each other. There are only a couple of species that have opposite branch structures, Ash and Maple. This isn't a maple. I can't tell for sure how many there are in the picture, but there are usually 5 to 9 leaflets on an Ash tree leaf. Another trait is the diamond shapes in the bark which you can see in the pictures.
I'm pretty sure it is an Ash, but I don't know what variety.
Dave, I found an interesting App for my i-Phone. It's name is "Leaf Snap". The icon is a black background, and a green leaf/stem enclosed within a green circle. It offers many photos of leaf, foliage, blooms, and bark, plus tree statistics. IT WAS FREE. I'm sure it is also available for Android phones. That way if one is afield you have an instant pocket guide. There is also a provision for photographing and other options. Good luck.