Time spent in the natural world benefits human health

Below Article appeared originally in The American Scientist.
July-August 2011Volume 99, Number 4 Page: 301

A Walk in the Woods » American Scientist.

A Walk in the Woods

Evidence builds that time spent in the natural world benefits human health

Anna Lena Phillips

For the month of April, I decided to visit the Haw River, which flows near where I live, every day. I wouldn’t hold myself strictly to this, but I would try, and I would observe—not impartially, of course, but closely—how I felt. Some days I took leisurely walks with friends, leaning over the railing of the pedestrian bridge to watch the river, high from recent rains, and to smell the distinctive, muddy smell of the water mingled with that of the banks overrun with invasive honeysuckle. On others, coming home late at night, I drove straight down to the bridge and walked out to stare down at the dark water, a move that felt a bit like the natural-world equivalent of visiting a drive-through restaurant.

I did this because I hadn’t been spending much time at the river, even though it’s only a short walk from home, and even though I like doing it. The results of my informal experiment? I did, in fact, feel better—calmer, more relaxed, clearer-headed. I suspect that many people have similar feelings about the effects of spending time in the wilder places near where they live. Perhaps that’s why Richard Louv’s 2005 book Last Child in the Woods, which explores the relation between the natural world and children’s development, became a bestseller in the United States.

2011-07SciObsPhillipsFA.jpgClick to Enlarge ImageBut to know empirically that these experiences are beneficial—and to know exactly how they might help us—requires more than personal experience. A growing and varied body of research attempts to quantify how and why spending time in the natural world might have beneficial effects on humans’ physical and psychological health. One of the first and most well-known studies, published in Science by Richard S. Ulrich in 1984, found that patients recovering from surgery in rooms with a window facing a natural setting had shorter hospital stays and took less pain medicine than did patients whose window faced a brick wall. Since then, researchers have asked whether the presence of trees influences people’s sense of safety in inner-city neighborhoods; explored how gardening might improve quality of life for people with disabilities; and used physiolgical measures to test for restorative effects of natural environments. If some of these studies seem too specific to be useful in answering the broader question, their results in sum suggest that time spent in nature improves human health. The more difficult questions are how, and in what ways, these effects arise. These questions are not the kind that can be answered by a single, groundbreaking paper; rather, like so many of the subtle and complex problems science explores, the evidence is being deposited, small study by small study, like layers of sediment on a river bed.

One such body of work is accumulating in Japan, where researchers are investigating the physiological effects of shinrin-yoku—“forest bathing,” or, to put it plainly, taking walks in the woods. Qing Li, a professor in the Department of Hygiene and Public Health at Nippon Medical School, Tokyo, has been involved with several such studies. He and his colleagues recently measured specific physiological markers before and after study subjects took walks in a forest and in an urban control environment. The study’s sample size is small—16 male subjects—and the timescale short—effects were measured after one day trip to the forest and one to the city—but the results suggest that the forest trip had positive effects on health. Subjects’ blood pressure measured in the forest was significantly lower when compared to measurements taken in the city. Levels of the stress hormone noradrenaline, measured in urine, were also significantly lower after the forest walk than after the urban walk. And blood levels of the adrenal hormone dehydroepiandrosterone sulfate (DHEA-S) and of adiponectin, a hormone secreted by fat tissue, were higher after the forest walk but not the urban walk. The authors note that DHEA-S may contribute to heart health, among other benefits, and that lower levels of adiponectin are associated with obesity and type 2 diabetes.

Li and his coauthors, whose study appeared in the European Journal of Applied Physiology in March, speculate that the forest trip’s effects on blood pressure may be related to phytoncides, volatile organic compounds (VOCs) that plants produce and release as protection from fungi and bacteria. In a separate study for which Li was also lead author, researchers unsurprisingly found higher concentrations of several phytoncides in a forest than in an urban area of Tokyo.

Another recent study, by Juyoung Lee, a researcher at the Center for Environment, Health and Field Sciences at Chiba University, Japan, and others, offers similar results. In this three-day field experiment, 12 young male subjects visited forest and urban environments. The study, published in February in Public Health, found that in the forest, subjects’ parasympathetic nervous-system activity was heightened and their sympathetic nervous-system activity suppressed. Pulse rates were lower, as were salivary levels of the adrenal hormone cortisol, which is associated with stress. Participants reported that their positive feelings increased, and negative feelings decreased, in the forest. Blood-pressure measurements, however, did not differ significantly between the forest and urban locations. The authors also measured phytoncide levels in the forest study area and found 10 different compounds, ranging in concentration from 0.3 micrograms per cubic meter to 1,336 micrograms per cubic meter.

In support of the idea that phytoncides may be responsible for some of the health effects seen in Li’s study, he and his coauthors cite a 2003 paper that found that inhalation of cedar-wood oil lowered blood pressure. A review article of forest-bathing studies, published in Environmental Health and Preventive Medicine in 2009 by Yuko Tsunetsugu and others, notes several laboratory studies that tested human responses to inhalation of plant VOCs. The results included such positive effects as lowered blood pressure and improved task performance. But to find a correlation between the mixture of phytoncides in forest air and physiological changes in humans would require experiments of more complex design. So although the idea that the very scent of the forest might improve health is appealing, determining whether it’s true and the extent of any effects will need more study.

This is just one of many avenues of inquiry that forest-bathing research opens. Can the physiological effects of studies like Li’s be replicated in larger studies, and in women and children? Do effects differ across gender and age? Do forests in varied bioregions, with different microclimates and compositions of tree species, vary in their effects on health? Do people who have grown up in one region experience different health effects in forests in their home bioregion than in other forests?

Policy questions abound as well. Carol Colfer, a cultural anthropologist and senior associate with the Center for International Forestry Research in Bogor, Indonesia, studies human use of forests in developing countries. “I suppose the logical result would be developing more or at least maintaining existing parks in cities, and expanding protected areas—but with much more serious attention to the human rights of people living in these areas,” she says of Li’s study. “Even better would be encouraging in situ conservation on people’s own lands.” Li is interested in exploring how his results could be used in medicine. “I am planning to develop forest bathing to be a preventive measure for some diseases such as depression, hypertension and cancers,” he says.

 

What’s clear is that trying to quantify a seemingly intuitive claim—humans benefit from spending time in the natural world—is turning up more complex answers, and more resulting questions, than a fir tree has needles. If policymakers take note of this work as it emerges, they might be better equipped to improve public health. For my part, I’ve extended my efforts to visit the river each day into the month of May. The weather’s better for swimming now, and the air smells as good as ever.

Eastern Screech Owls -an Album

In early June momma Screech brought two little fluffy Owlets around to show.  They were barely flying – more like bombing around … and they were very needy with their calls for food!    Here is mom below, with one of her fledgling chicks.  I have a long relationship with the screech owls around our neighborhood and every year we get to see them as they perch and hunt in and around our half acre for insects here in Lehigh.  
The tree below is over our Labyrinth and I was sitting under it when she brought them by.  Yes, I try to always have a camera on hand in the Backyard Universe just in case!  
Mom and Owlet

Mom and Owlet

Above and below a fluffly barely fledgling Screech closer up, sitting in the tree above with mom.  Mom had left them up in the tree overhead while she went off to hunt in daylight.  The only issue is, during daylight hours they can be attacked by other birds that find them and this was an open area.  I helped mom out and kept the mocking birds and jays away while the little ones sat up in the tree calling for mom to bring them yummy beetles from nearby backyards.  They were not that far from their nest in a clump of Sabal Palms behind our lot.  (We let our native yard grow tall and wild in the back for cover and hunting areas for the little ones.)  
Fluffly chick

Fluffly chick

In the below images they are much older but still sporting some pin feathers.  The don’t need mom to watch after or protect them from attacking birds.  They know to hide in the shadows during daylight hours until nightfall.

Fledgling1_01

Hiding in among the Bombax tree leaves… a wide eyed fledgling Screech.  300mm Nikon lens

Other Fledgling

I am outside, after dinner looking for the screeches.  Sometimes after a rain I hear them or late at night calling with their soft whinny call…  Eventually they will move out to other areas of the neighborhood to hunt over the Summer.  I hope they are greeted with as much awe, enjoyment and safe haven as they are met with here on the half acre.  Owls like this hunt insects, small bats, mice and snakes.  In yards sprayed with pesticides, they may suffer through their food sources that are impacted by the pesticide applications.  
I have found that when our rodent or snake numbers go up here at the Backyard Universe that we often see an influx of hawks and owls to feed on them.  It’s an intricate, connected age old cycle that will balance itself  out if we allow it to and don’t interrupt it via artificial and deadly means.  If you would like to build Screech Owl Nest Boxes for your yard, go to this link  in my prior article and read down it for the link to the nesting box instructions.
 

Weekly Photo Challenge: Green

This post is in response to the Word Press Weekly Photo Challenge  of the color GREEN.  I  also want to apologize for a month of non postings.  Scheduling issues, as well as health things got in the way of creativity.  But I should be back on track now to pick up the blogging so I hope you’ll stay with me and explore the richness of your backyard and community.  There really is allot to see out there and the first step to exploring it, is to go outside.  

To see the individual images larger, please click on them.

My choices for Green include a selection of small green insects, birds and amphibians you are likely to encounter either in your Florida backyard, or on a boardwalk at your local Nature Center or Preserve.  All of these green critters are quite small and can easily be missed if you’re hurried.  The Green Tree Frogs are found during the day resting up or hidden in leaves or along board walks.  The Green fly pictured on the big leaf is out in our yards daily, hanging around foliage, feeding off of rotted plant material.  The beautiful Iridescent Sweat Bees are normally found close to your grasses.. they move fairly slow so they are easy to follow around and study although I have seen them hovering high over trails at almost eye level when you step into their territory – last Friday I was able to hang around a good while watching their antics over the CREW Land and Water Trust trails.  

The Florida Green Anole can be a bit harder to find.  They have been replaced in many areas by invasive lizards (like the brown ones on your porches and lanais)  and loss of habitat.  This Anole is from Corkscrew Swamp Sanctuary, there you can find them along the boardwalks and on Alligator Flag leaves enjoying the sun, and looking for insects.  The beautiful, delicate Juvenile (he does not have his red throat yet) Ruby Throated Hummingbird is attracted to red flowers like Native Firebush, Red Shrimp Plants.  Vines, trees, and shrubs that attract hummers include honeysuckle, morning glory, trumpet creeper, albelia, butterfly bush, flowering quince, rose of sharon, weigela, flowering currant, rosemary, buckeye and horsechestnut, black locust, flowering crabs, hawthorns, mimosa, and tulip poplar.  I’ve also seen them feeding on the orchid like flowers of Bombax trees.  I hope you have enjoyed my selection of  “Green” and that it inspires you look around your local habitat for more of… the little things…         all photography by Linda S. Jacobson.

To see the individual images larger, please click on them.

Click here to visit my Artist Website

Weekly Photo Challenge: Happy

This Gallery and Blog is in response to The  Word Press Weekly Photo Challenge.  I just felt I had to make that clear since I normally write about Backyard Nature topics  🙂   and normally include some imagery in it from my backyard – you know, spiders, mushrooms, butterflies, birds  etc..  those type of things.  Not the Happy Faced Chihuahuas, Rosie Doodles and Luna, running around in my yard while I’m out there   🙂    Word Press has rolled out a new cool Display Mosaic that I had to include with the new Weekly Photo Challenge.  I think it is pretty neat.

But back to the topics at hand!   Luna and  Rosie Doodles….
They BOTH have their own FB page  and following, and are total hams.   And very photogenic I might add.  I got Luna first she is AKC, and the most docile laid back easy going Chihuahua you will ever see.  She loves to go to Home Depot and ride in the cart  and she contrasts totally with Rosie Doodles, who is also 100% Chihuahua (big attitude)  Rosie being a feisty, bossey  little thing.  I got Rosie through my Vets office, she was surrendered to them by a gal who said Rosie “was not affectionate.”   Well I can tell you, Rosie has a HUGE attitude, typical of Chihuahuas, and she is VERY affectionate.  Rosie is originally from Oklahoma where she was used in a breeding operation.  She’s had three moms, and I’m the only one she has stuck to.

They are our fur kids and they go everywhere with us including Glamping in the Florida State Parks.  When I’m out in the yard photographing some new butterfly or a new cool insect, they are out there with me in the half acre running around with those happy smiley faces on.  If you’d like to keep up with them, join their Face Book page.

When nature Photobombs..

I enjoy going out in the mornings photographing flowers around the half acre.   Both the native and non-native flowers.  This big, bright hibiscus bloomed a couple of days ago which made it an immediate target for an iPhone image, taken with the CameraAwesome app.  I took quite a few images to get one image that hopefully was decent enough to possibly offer a print of (not .)   However, when I got inside and examined the images, I found that I had been PhotoBombed!  At the time I had not noticed they were there… hiding out in the leaves…  but now, they stand out.  And they are in every image that I took.   Do you see them?   Look closely.

I have seen a lot of Photo Bombed images with horses, cats, dogs etc.. bombing someones image.  
But I had never ran across these guys.  Do you see them  yet?

Look closer..

 

Now you see them, and after a while their bright red color will stand out!  A pair of amorous Red Bugs, of which there are four species here in Florida and I think I have, at one time or another, ALL of them in my yard!  These particular ones are called Cotton Stainers.  Dysdercus suturellus.   In 1910  the cotton stainer was a most destructive pest to Cotton in Florida.  

Cotton Stainers lost their dominance on cotton in the mid-twentieth century primarily because of the elimination of it as a viable crop, and the development of pesticides.  Cotton stainers are obviously still around doing damage to some fruits and ornamental plants like my Hibiscus.  Stainers suck juices out of plants, sometimes killing them.  They also PhotoBomb.   No I didn’t kill these guys, I just picked them off my plant and gave them a good lecture!

 

New overnight surprise in the labyrinth.

Fall is coming!   another sure sign is this little Stinkhorn (Order Phallales)  that popped up in the Labyrinth overnight.  Stinkhorns are found October through March from North Carolina to Florida, to along the Gulf Coast as well as in Mexico.  I love mushrooms, in all of their variety, both canned or grocery store fresh on my pizza as well as along the trails that I wander.  

Stinkhorns are comprised of several columns that are fused at the top.  Supposedly they stink and are “fetid”  although I didn’t get down-that-close to see if it had an odor to it  (getting up would have been another matter. )  

However I did notice that it had ants under its cap and if you click on this image, you can see the fungus up close, along with the ants.  These strange little guys rise out of the ground from a body or “egg” that is hidden underground.   Long cords help to form the arms that reach skyward with the interior of the arms covered with a slime.  It’s this slime and the smell, which attracts flies, that helps to disperse the spores.  

I’ll definitely be keeping my eye on this one today to see how it’s getting along.    Just another reason to always be looking for the little things underfoot.  What’s happening in your yard today?     This is an iPhone4S image taken with ProHDR

What the Fairies left behind…

 

 

Like little cabochons of exquisite crystal, dew decorates a little leaf looking all the world like a fairies brooch, ready to wear.  I like to think the fairies will be back to collect this jewel, left behind in the Labyrinth for all to enjoy.