Other than junk and/or scrap and auto wrecking yards, all open storage shall be located within an area not closer than 50 feet from any street right-of-way line and shall be enclosed with a greenbelt planting strip, or other approved screening, not less than eight feet in width, and not less than eight feet in height, to normally screen view of stock piles. The storage of lumber, coal or other combustible material shall not be less than 20 feet from any interior lot line, and a roadway shall be provided, graded, surfaced and maintained from the street into the property to permit free access of fire trucks at any time.