“The tonic of the wilderness was Henry David Thoreau’s classic prescription for civilization and its discontents, offered in the 1854 essay Walden: Or, Life in the Woods. Now there’s scientific evidence supporting eco-therapy. The Japanese practice of forest bathing is proven to lower heart rate and blood pressure, reduce stress hormone production, boost the immune system, and improve overall feelings of wellbeing.
Forest bathing -- basically just being in the presence of trees -- became part of a national public health program in Japan in 1982 when the forestry ministry coined the phrase shinrin-yoku and promoted topiary as therapy. Nature appreciation -- picnicking en masse under the cherry blossoms, for example -- is a national pastime in Japan, so forest bathing quickly took. The environment’s wisdom has long been evident to the culture: Japan’s Zen masters asked: If a tree falls in the forest and no one hears, does it make a sound?
To discover the answer, masters do nothing, and gain illumination. Forest bathing works similarly: Just be with trees. No hiking, no counting steps on a Fitbit. You can sit or meander, but the point is to relax rather than accomplish anything.
Forest air doesn’t just feel fresher and better -- inhaling phytoncide seems to actually improve immune system function.
“Don’t effort,” says Gregg Berman, a registered nurse, wilderness expert, and certified forest bathing guide in California. He’s leading a small group on the Big Trees Trail in Oakland one cool October afternoon, barefoot among the redwoods. Berman tells the group -- wearing shoes -- that the human nervous system is both of nature and attuned to it. Planes roar overhead as the forest bathers wander slowly, quietly, under the green cathedral of trees.
From 2004 to 2012, Japanese officials spent about $4 million dollars studying the physiological and psychological effects of forest bathing, designating 48 therapy trails based on the results. Qing Li, a professor at Nippon Medical School in Tokyo, measured the activity of human natural killer (NK) cells in the immune system before and after exposure to the woods. These cells provide rapid responses to viral-infected cells and respond to tumor formation, and are associated with immune system health and cancer prevention. In a 2009 study Li’s subjects showed significant increases in NK cell activity in the week after a forest visit, and positive effects lasted a month following each weekend in the woods.
This is due to various essential oils, generally called phytoncide, found in wood, plants, and some fruit and vegetables, which trees emit to protect themselves from germs and insects. Forest air doesn’t just feel fresher and better -- inhaling phytoncide seems to actually improve immune system function.
Experiments on forest bathing conducted by the Center for Environment, Health and Field Sciences in Japan’s Chiba University measured its physiological effects on 280 subjects in their early 20s. The team measured the subjects’ salivary cortisol (which increases with stress), blood pressure, pulse rate, and heart rate variability during a day in the city and compared those to the same biometrics taken during a day with a 30-minute forest visit. “Forest environments promote lower concentrations of cortisol, lower pulse rate, lower blood pressure, greater parasympathetic nerve activity, and lower sympathetic nerve activity than do city environments,” the study concluded.
In other words, being in nature made subjects, physiologically, less amped. The parasympathetic nerve system controls the body’s rest-and-digest system while the sympathetic nerve system governs fight-or-flight responses. Subjects were more rested and less inclined to stress after a forest bath.
Trees soothe the spirit too. A study on forest bathing’s psychological effects surveyed 498 healthy volunteers, twice in a forest and twice in control environments. The subjects showed significantly reduced hostility and depression scores, coupled with increased liveliness, after exposure to trees. “Accordingly,” the researchers wrote, “forest environments can be viewed as therapeutic landscapes…”
-- Ephrat Livini, from “The Japanese practice of ‘forest bathing’ is scientifically proven to be good for you,” World Economic Forum Agenda, March 23, 2017
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Several articles about “forest bathing” have appeared in recent years, and I’ve discussed the subject here previously. The above article takes another look.
The therapeutic benefits of spending time in the woods aren’t exactly news to hikers, who tend to return home after a hike feeling pretty refreshed and renewed.
And although this latest article emphasizes that you don’t have to hike or accomplish anything to receive rewards, hiking can actually multiply the benefits.
The expression “forest bathing” is, in part, a new way to frame spending time in the natural world, specifically in the realm of trees and (preferably wild) forests.
It’s interesting that extensive research has been carried out in Japan that shows potentially remarkable benefits from simply spending time near and among trees.
We can suspect as well that being in the presence of plants and other living things similarly has positive effects that someday may be understood and appreciated.
The results of forest bathing research have led to new health programs in Japan, California, and elsewhere, and some health spas now offer forest bathing sessions.
But those of us who are hikers don’t need to do anything differently. When we venture out into the natural world, out into the splendid mountain forests of the Northeast, we’re getting a wonderful dose of forest bathing every time we go.
-- Charlie Cook