That area set aside for the growing of vegetation, including trees, bushes, grass, flowers and plants, and also including lakes, ponds, streams and other natural features, maintaining as much as possible any existing natural growth. "Green area" may include walkways for nonvehicular traffic only. Areas set aside for recreational use shall not be counted as "green area," except that those areas devoted exclusively to golf course use, including a driving range when conducted as an accessory use thereto, but not including a miniature golf course nor any nighttime golf course activities, may be counted toward the requisite "green area."