Deep Seated Need for Nature 
http://www.livescience.com/6399-5-minutes-nature-boost-mental-health.html  

Stanford
 http://news.stanford.edu/news/2015/june/hiking-mental-health-063015.html    
 

Time Spent in Nature
http://www.aarp.org/politics-society/advocacy/info-07-2012/health-benefits-of-nature.html 

Natural Stress Buster
http://www.aarp.org/politics-society/advocacy/info-07-2012/health-benefits-of-nature.html 

Psychological Well Being
http://naturalsociety.com/time-nature-boost-mental-health-veterans/%23ixzz2s4gkpGVf