wondering about wandering

The Globe and Mail asks why is walking in the woods good for you?

In Japan, they call it shinrin-yoku - literally, "forest bathing." Here, we might just call it a walk in the park. Either way, people around the world have an intuitive sense of the restorative power of natural environments. The question is: Why?

Scientists have advanced a wide range of theories about the specific physical and mental benefits nature can provide, ranging from clean air and lack of noise pollution to the apparent immune-boosting effects of a fine mist of "wood essential oils."

The physical pleasures may be dwarfed by something less obvious, as "the most powerful benefits, a new study suggests, may result from the way trees and birds and sunsets gently tug - but never grab - at our attention:"

Dr. Berman and his colleagues believe that going for a walk in the park gives voluntary attention a break, since your mind has a chance to wander aimlessly and be engaged - involuntarily but gently - by your surroundings. [...] In contrast, honking horns and traffic lights and crowded sidewalks - and pretty much every other ingredient of modern life in a big city - constantly force you to exert your voluntary attention to react or block them out, leaving you more cognitively depleted.

The piece cautions that "[t]easing out the key variables will take time:"

...and ultimately, it seems unlikely that there's a single magical quality or essential oil that fully explains the call of the semi-wild. For now, it's enough to know that the benefits of exposure to nature are real and measurable. And in an increasingly distracting and distracted world, they're more important than ever.

update (5/31):
WSJ has something to add, courtesy of psychologist Ruth Ann Atchley at the University of Kansas:

To measure the mental benefits of hiking in the middle of nowhere, Dr. Atchley gave 60 backpackers a standard test of creativity before they hit the trail. She gave the same test to a different group of hikers four days into their journey.

The results were surprising: The hikers in the midst of nature showed a nearly 50% increase in performance on the test of creativity, and the effect held across all age groups.

"There's a growing advantage over time to being in nature," says Dr. Atchley. "We think that it peaks after about three days of really getting away, turning off the cellphone. It's when you have an extended period of time surrounded by that softly fascinating environment that you start seeing all kinds of positive effects in how your mind works."

How many of us can disconnect for that long?