Not sure what it is, but it's not hickory or black walnut because the leaflets are not toothed, or at least they don't look toothed to me in the pictures. I can't really see the berries clearly in the tree pictures to get an idea of their size in relation to the leaves. In the top picture the perspective may be making them look bigger than they are. Is it possible to get a picture that more clearly shows their relative size?
Edited to add, it does rather look like soapberry as Porkpal suggested. Apparently western soapberry grows to 35 feet.
