Section 18-105. Trees under private or public ownership; care and cultivation

All trees in streets, which on investigation are found  to  be  without ownership, shall be under the exclusive care and cultivation
  of the  commissioner,  and  such  commissioner  shall  employ  the  most
  improved  methods  for  the  protection  and  cultivation  of  the trees
  selected for preservation, and  remove  those  condemned  as  unfit  for
  cultivation.  Trees  found  to  be  in  the  care  of individual owners,
  corporations, societies, or associations, shall not be  subject  to  the
  jurisdiction of the commissioner, unless the owners thereof make written
  application to the commissioner to have such trees transferred to his or
  her  care.  If  the commissioner approves such transfer, he or she shall
  forthwith assume full control thereof and  the  former  owner  shall  be
  relieved of all expense connected with the cultivation of such trees. In
  all  cases  where  land-owners, societies or associations elect to plant
  and cultivate their own trees in streets, such planting and  cultivation
  must  conform  to the rules and regulations adopted by the commissioner.
  The commissioner  may,  however,  on  the  written  application  of  any
  land-owner,  plant  and  cultivate trees on the streets adjoining his or
  her land and charge for such service an amount not to exceed the  actual
  cost to the department for labor and materials.