Davey: Davey Arbor Green? <i>PRO</i>
The link is to what Davey has to say about it.
My experience tells me that overall in urban areas fertilization is a huge improvement. Certian trees though(specifically magnolias and tulip tree) when already infested with aphids or scale, seem to do worse than if not fertilized. I cant prove this scientifically, just observation from personal experience.
Also, I have accidentally hugely overdosed a tree with the stuff and it did no apparent dammage at all.