Forest walking is better for your health than urban walking for cardiovascular and metabolic health according to Japanese research http://www.hphpcentral.com/article/where-you-walk-matters
Original Paper: Qing Li; Toshiaki Otsuka; Maiko Kobayashi; Yoko Wakayama; Hirofumi Inagaki; Masao Katsumata; Yukiyo Hirata; YingJi Li; Kimiko Hirata; Takako Shimizu; Hiroko Suzuki; Tomoyuki Kawada; Takahide Kagawa Acute effects of walking in forest environments on cardiovascular and metabolic parameters European Journal of Applied Physiology (November 2011), 111 (11), pg. 2845-2853