From The New York Times:
How Walking in Nature Changes the Brain
A walk in the park may soothe the mind and, in the process, change the workings of our brains in ways that improve our mental health.
SWTRAILS-PDX
A community group promoting walking and biking in southwest Portland, Oregon by:
1. Leading regular monthly hikes.
2. Organizing volunteer work parties to build and maintain trails.
3. Working with city, county and state planners to develop safe pedestrian routes.
4. Advocating for safe walking/biking in southwest Portland.