Up to three members may be appointed from among professionals in the disciplines of architecture, history, architectural history, planning, or other historic preservation-related disciplines, such as urban planning, American studies, American civilization, cultural geography, or cultural anthropology, to the extent that such professionals are available in the community and wish to serve on the board. At least two members shall be lay members who have demonstrated special interest, competence, experience, or knowledge in historic preservation, American studies, cultural anthropology, cultural geography, or other historic preservation-related disciplines.