For the 18 years I lived in Brooklyn, the trees were never maintained by the city. Our block association planted them in the late sixties, and the houses on eit

For the 18 years I lived in Brooklyn, the trees were never maintained by the city. Our block association planted them in the late sixties, and the houses on either side watered them when they were hosing their own sidewalks (as well as keeping all the stray dogs from shitting and pissing in their soil!). I remember only one incidence of the city being called in, or a private contractor to repair the sidewalk by the two oldest oaks on the bottom of the block whose roots had lifted and cracked the walkway. They just expanded the opening; I'm sure it was not up to code after for width between the areaway fence and the tree's opening in the sidewalk. I can't believe it costs much to maintain them after the initial cost of planting them. I never had to care much for the trees on my property in NJ either, other than pruning some dead limbs that were about to fall over my access way or roof from the taller trees. The younger trees did fine on their own. Although, almost all of the hemlock trees succumbed to the Gypsy moths, but even neighbors who spent thousands on trying to save theirs, suffered almost the same number of losses. I was also not quick to cut them down if they didn't 'look' right. Now one that neighbors said looked dead, is thriving again!