N.Y.C. Admin. Code § 18-106: § 18-106 Tree planting; permission of commissioner of transportation.

In performing the duties required by sections 18-104 and 18-105 of this title, the commissioner shall not make openings or excavations in any street for the purpose of planting or cultivating trees, without having first obtained the written approval of the commissioner of transportation nor shall any tree be so planted as to permanently interfere with the ordinary usage of the street, nor shall the planting be performed in any case so as to injure or impair any sewer, drain, water pipe, or other structure erected by legal authority.