No person, firm or corporation without a written permit from the Director of Public Properties shall cut, break, climb or injure any tree or portion of tree planted or growing in any public highway within the City or cause, authorize or procure any person to cut, break, climb or injure any such tree or portion thereof; cut, break, climb or injure any tree or plant, or injure, misuse or remove, or cause, authorize or procure any person to injure, misuse or remove any device set for the protection of any tree or plant in any public highway of the City. Any person, firm or corporation desiring for any lawful purpose to cut, prune, treat, with a view to its preservation from disease or insect, or trim any tree in any public highway of the City, may apply to the Director, and if in the judgment of the Director the desired cutting, pruning, treatment or trimming appears necessary and the proposed method and workmanship thereof are such as the Director approves, the Director may thereupon issue a written permit for such work. Any work done under such written permit must be performed in strict accordance with the terms thereof.