Q. Can you recommend a small shade tree for an urban garden?
Eastern Redbud (Cercis canadensis) is a fine tree. Others you might consider are:
Acer griseum – Paperbark Maple
Cornus kousa – Kousa Dogwood
Parrotia persica – Persian Parrotia
To get an idea of what these trees look like, you can search the above Latin names in Google images.
Three books with good recommendations for trees:
Diana Miller’s 400 Trees and Shrubs for Small Spaces (Timber Press, 2008).
Simon Toomer’s Trees for the Small Garden : How to Choose, Plant, and Care for the Tree That Makes the Garden Special ( Timber Press, 2005.)
Michael Dirr’s Dirr’s Hardy Trees and Shrubs. These books are available in the PHS McLean Library.