mel turner schreef
Your tree, on the other hand, seems to have simple, toothed leaves.
I'd thought that the only simple-leaved ash species was _Fraxinus
anomala_ from the southwest, but its foliage appears rather different
from yours:

http://www.suu.edu/faculty/martin/as...leleafash.html

However,
http://ohioline.osu.edu/b700/b700_63.html

says that one commonly cultivated form of _Fraxinus excelsior_
[European Ash] has simple leaves. That's my best guess as to the
identity of your mystery tree.

*****
I remember that Fraxinus angustifolia 'Monophylla' also has simple leaves
(compound leaves with a single leaflet). As can be read from the name this
is a fairly old cultivar. Its leaves will be rather more narrow.
PvR