Buffers. The mobile home development shall have a permanent landscaped planting area of at least 15 feet in depth designed for screening residential commercial and industrial uses which are adjoining and contiguous. The buffer shall be a minimum of six feet in height. The use of mounding shall be encouraged as a means of providing screening, provided that their slope shall be a maximum of 3:1. In cases where an edge(s) of a mobile home development borders natural features which function as buffers, including but not limited to mature woodland, severe grade changes or stream valleys, buffering may not be required along that edge(s), at the discretion of the Board of Supervisors. A landscaping plan shall be submitted with the final plans, showing all pertinent information including the location, size and species of all trees and shrubs to be preserved or planted.