Ann Arbor won't have all that much in the way of arbors in the future; the city council of "Tree City USA" is planning a new law establishing solar access boundaries on properties, and looking at vegetation trimming standards and building setback requirements. Why?
Because they want people to spend money sticking solar panels on the roofs of their homes, and the darned trees will eventually interfere with that grand plan. It's amusing; here in Green&Sustainable Portland, you have to spend hundreds to thousands of dollars for a permit to trim or remove a tree on "your property" - and if you remove a tree, you must replant one from the city's approved tree list. If you don't, they'll do it and bill you $500 whether you like it or not. Ann Arbor seems to be moving in a diametrically opposite direction.
They don't want people's trees or structures throwing shade on the solar arrays of the neighbors. Property rights? What are those?