I just tumbled into Frances Kuo's "Landscape and Human Health Laboratory" website at the University of Illinois.  Fascinating.  I can remember the past internal admonition to "exercise the children" if we wanted more peace and quiet later in the day.  Much the same kind of internal/shared dialogue as we now have over the grandchildren.  Interesting then to see Kuo & colleagues reporting " ... that performing activities in green settings can reduce children's Attention Deficit-Hyperactivity Disorder symptoms. In an initial, Midwestern-based survey, parents of children with AD/HD were more likely to nominate activities that typically occur in green outdoor settings as being best for their child's symptoms and activities that typically occur in indoor or non-green outdoor settings as worst for symptoms ... In the subsequent, nation-wide survey, parents again rated leisure activities-such as reading or playing sports-as improving children's symptoms more when performed in green outdoor settings than in non-green settings.  A more recent study tested children with AD/HD in a controlled setting after they had walked in one of three environments that differed from one another in the level of greenery:  a park, a neighborhood, and a quiet downtown area.  The findings confirmed that the attention of children with AD/HD functions better after spending time in more natural settings.  AD/HD affects up to 7% of children."   And we know that ADHD-like symptoms are distributed throughout the population - see, for example, the recent paper "Maternal Ratings of Attention Problems in ADHD: Evidence for the Existence of a Continuum."

And what about adults?  Well, Kuo et al go on to report that "In a study conducted in a Chicago public housing development, women who lived in apartment buildings with trees and greenery immediately outside reported greater effectiveness and less procrastination in dealing with their major life issues than those living in barren but otherwise identical buildings ... women who reported better coping had better scores on a test of concentration, and living in a greener home was also linked to having better scores on that same test ... even small amounts of greenery-a few trees and a patch of grass-helped inner city residents to feel and do better."  Further papers on Kuo's website describe effects on rates of domestic violence, on crime levels, and on "feelings of community". 

Happily other researchers have also been interested in these kinds of findings.  Recent examples of this exploration include "Green space as a buffer between stressful life events and health", "Vitalizing effects of being outdoors and in nature", "The relationship of physical activity and overweight to objectively measured green space accessibility and use", "Can nature make us more caring? Effects of immersion in nature on intrinsic aspirations and generosity" and "A systematic review of evidence for the added benefits to health of exposure to natural environments".  Just last month a paper in the Journal of Environmental Psychology - "Walking in "wild" and "tended" urban forests: The impact on psychological well-being" - reported (somewhat counterintuitively) " ... participants were randomly assigned to either a walk through wild or tended forests for 30 min. Multidimensional scales in a pre-post-treatment-setting measured well-being. Results indicate a stronger change in "positive affect" and "negative affect" in the tended forest condition ... Furthermore, more and less fatigued persons did not profit differently concerning well-being changes." 

Town planners please take note!