Oral or written testimony shall be taken at the public hearing from any person concerning the nomination. The preservation commission may solicit expert testimony or present its own evidence regarding the historic, archaeological, architectural, or scenic significance of a proposed landmark or of any property within a proposed preservation district. The owner of any proposed landmark or of any property within a proposed preservation district shall be allowed reasonable opportunity to present evidence regarding historic, archaeological, architectural or scenic significance and shall be afforded the right of representation by counsel and reasonable opportunity to cross examine expert witnesses. The hearing shall be closed upon completion of testimony.