Parcels which have been designated by the County General Plan for future acquisition and/or development in whole or part for Neighborhood, Community, or Regional Parks shall be placed in a Designated Park Site “D” Combining District. Other properties designated in the County General Plan for any other type of future public recreational use may be placed in a Designated Park Site “D” Combining District at the discretion of the Board of Supervisors following a recommendation from the Planning Commission.