Upon the recommendation of the commission, the governor may declare by public order any particular historic, prehistoric, or archeological structure, deposit, site, or other object of scientific or historic interest that is situated on land owned or controlled by the state to be a state monument or historic site, and the governor may designate as a part of the monument or site as much land as is considered necessary for the proper access, care, and management of the object or site to be protected. When an object or site is situated on land held in private ownership, it may be declared a state monument or historic site in the same manner, with the written consent of the owner.