I think, at least partially, "civil engineers" - good to know where trees are as an indication of potential root problems with pavements, pipes, conduits, etc. Also for things like "where might we have road overhang problems" - if it's a conifer, probably ok, but if it's a London Plane, that might be an issue.

Oh and also to know where to send the horrifically noisy leaf blowing man who spends half his life outside in the square revving his diesel abomination.