Section 8. The mayor in cities, subject to charter provisions, and, except as provided in section forty-three, the selectmen in towns, shall annually, in June, appoint a forest warden, and forthwith give notice thereof to the commissioner of environmental management, in this chapter called the forester. The same person may hold the offices of tree warden, selectman, chief of the fire department and forest warden. The forest warden so appointed shall hold office for one year and until his successor is appointed and qualified. Upon the failure of the mayor of a city or the selectmen of a town to make such appointment in the month of June or within thirty days after the office becomes vacant through any cause, the forester shall notify the mayor or selectmen so to do, and if the mayor or selectmen fail to comply within fourteen days after receipt of such notice, the forester may appoint as forest warden in such city or town a suitable person, who shall be a resident thereof.