Screening adjacent to residence districts. The minimum setback area adjacent to a lot in a Residence A, Residence B, Residence Lake Front or Agricultural district shall be maintained in a wooded state to provide effective year-round screening of abutting property. All outdoor activity in a BR District, including parking, shall be screened as viewed from the ground. Acceptable screening may be a band of dense natural woodland 20 or more feet wide, differences in elevation sufficient to shield the view as required, an opaque fence or wall or evergreens planted to form a dense hedge of the required height within three years.