Many studies have shown that children’s stress levels are going up – with busy schedules and increased emphasis on performance. Likewise, other studies have shown that being exposed to a natural environment can reduce stress.
One such study from the University of Washington measured heart recovery rates after minor stress. Subjects looked at a natural scene through a window, while others viewed the same scene on a high-definition plasma TV screen or a blank wall.
The heart rate of people who looked at the scene through the window dropped more quickly than the others. You can read more about the study in Science Daily http://www.sciencedaily.com/releases/2008/06/080610154746.htm