Protection of adjacent residential districts. Where development will abut a residential district, a buffer area must be provided at the rear and side lots zoned to the above district and such abutting residentially zoned lots. Approval of design of the buffer area by the Planning and Zoning Commission is required. The buffer shall have a depth of eight percent (8%) of the lot or fifty (50) feet, whichever is greater, unless the depth of the lot exceeds six hundred (600) feet, in which case the buffer strip shall be five percent (5%) of the depth of the lot or an average of forty-five (45) feet, whichever is greater. The buffer strip shall be at the same elevation as the adjacent residential lot or lots unless the Planning and Zoning Commission shall determine such to be impractical, in which case such Commission may impose additional requirements, in order to accommodate such fact, with regard to such things as the number of planted trees, size of trees, spacing of trees, or use of other methods of screening, such as fencing, so as to preserve the effectiveness of such buffer strip. At a minimum, such buffer strip shall be planted with evergreens a minimum of five (5) feet tall with a minimum diameter spread at the canopy base of three (3) feet and located in double staggered rows on ten (10) foot centers. Approved plant materials shall consist of Scotch Pine, Black Pine, Blue Spruce, Green Spruce, Juniper and Cedar. Said plants shall be maintained in a healthy condition or shall be replaced. Driveways and parking areas shall not be permitted in a buffer zone. If the Planning and Zoning Commission shall determine that the aforementioned buffer strip requirements are impractical, the Commission may impose additional or varied requirements in order to accommodate the development circumstances, such may include the erection of sound walls.