No person shall break, injure, mutilate, kill or destroy any tree or shrub within the street right of way or in the area between a sidewalk and the street right of way. No person shall knowingly permit electric wires to come in contact with any tree or shrub unless protected by approved methods. No person shall excavate any ditch, trench or tunnel within ten feet of any tree in the areas designated by this chapter without first obtaining a written permit therefor from the Director of Public Service.