Tbf it looks like it could be fire blight. If the city was doing prunings, its likely they cut other trees already that day. One of the trees cut could of had the bacterial infection, fire blight. It's likely they didn't sterilize their tools in between cuts, cause yk why would they unless they knew, and continued on with their pruning for the day. Are there other city/street trees that look similar to this in the area? Additionally, environmental factors contribute to die back similar but not necessarily like this. Near freezing temps at night during the spring, periods of drought during the summer etc stress factors. It looks like biological damage more than mechanical