The top picture is Parrotia persica, a smallish tree that was given the silly 'common' name of Persian ironwood. It's a refined witchhazel relative, very uncommon in Ann Arbor as of now -- one on the west side of 7th between Miller and Huron, a small one in the Arb, and a handful in people's yards. More on this wonderful landscape plant at a later date.
The second is Cornus mas, a dogwood that produces attractive clusters of small mustard-yellow flowers in the early spring, prior to forsythia. It seems to fly beneath people's radar, though it deserves much more respect. The 'common' name may be any combination of the words 'European', 'cornel', 'cornelian-cherry' and, of course, 'dogwood.' When I took this picture a couple weeks ago, it still retained a few of its red cherry-like fruits, which are edible and which are used in jams in Europe. Look for this plant next spring -- they are sprinkled all over town.