I called 311 and described the branch and the location of the tree. Today I happened to look out the same kitchen window and, voilà, a better looking view! Of course, the City pruned the dead branch only because the tree was located on the city-owned property adjacent to the avenue.
You can access a lot of information and services by dialing 311.
Disclosure: my wife, Carol, works for the City's Corporate Communications group so part of her job is to portray services like 311 in a good light.