@tntrecycling : The trees get old and brittle. Strong storms dump broken branches into the road and sometimes the whole tree falls over. Plus, as they grow, they can block the view when turning onto the road from a side street.
@tntrecycling : A lot of those 'tree lined' streets were likely built/planted around the same period of time. I imagine that at least some of the trees on those streets are starting to die off and become a hazard. It's cheaper to just clear the whole lot of them at once.
The trees taken down were too close to the road and the roots (a) were causing the pavement to heave and (b) would have been dug up/cut off due to construction which would have killed the trees anyway.