New study reinforces the importance of walking through forests for mental and general health

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I love trees and am not immune to hug­ging them. It may not be ratio­nal, but when I’m near one of these qui­et giants, I feel like they are kin—ancient grand­par­ents, or at least benev­o­lent wit­ness­es of his­to­ry and time.

Every­one prob­a­bly doesn’t feel the same way as I do, but per­haps they should. While being in nature leads to bet­ter health, cre­ativ­i­ty, and even kind­ness, there may be some­thing spe­cial about being among trees.

After all, trees are impor­tant to our lives in many ways. The most obvi­ous is their role in pro­duc­ing the oxy­gen we breathe and seques­ter­ing car­bon diox­ide to help pro­tect our atmos­phere; but sci­ence sug­gests trees pro­vide oth­er impor­tant ben­e­fits, too.

Here are some of the more provoca­tive find­ings from recent research on how trees increase human well-being.

Walking through forests lower levels of anxiety and stress

Prob­a­bly the most well-researched ben­e­fit of nature expo­sure is that it seems to help decrease our stress, rumi­na­tion, and anx­i­ety. And much of that research has been con­duct­ed in forests.

In one recent study, 585 young adult Japan­ese par­tic­i­pants report­ed on their moods after walk­ing for 15 min­utes, either in an urban set­ting or in a for­est. The forests and urban cen­ters were in 52 dif­fer­ent loca­tions around the coun­try, and about a dozen par­tic­i­pants walked in each area. In all cas­es, the par­tic­i­pants walk­ing in a for­est expe­ri­enced less anx­i­ety, hos­til­i­ty, fatigue, con­fu­sion, and depres­sive symp­toms, and more vig­or, com­pared to walk­ing in an urban set­ting. The results were even stronger for peo­ple who were more anx­ious to begin with.

“The psy­cho­log­i­cal ben­e­fits of walk­ing through forests are very sig­nif­i­cant, and for­est envi­ron­ments are expect­ed to have very impor­tant roles in pro­mot­ing men­tal health in the future,” the authors write. Indeed, var­i­ous oth­er stud­ies sug­gest that the prac­tice of “for­est bathing”—deliberately spend­ing time among the woods—can help us deal with the stress­es and strains of urban living.

In anoth­er recent study, Pol­ish par­tic­i­pants spent 15 min­utes gaz­ing at either a win­ter­time urban for­est or an unforest­ed urban land­scape. The trees in the for­est had straight trunks and no leaves (because of win­ter), and there was no oth­er shrub­bery below the trees—in oth­er words, no green; the urban land­scape con­sist­ed of build­ings and roads. Before and after, the par­tic­i­pants filled out ques­tion­naires relat­ed to their moods and emo­tions. Those who gazed at a win­ter for­est report­ed sig­nif­i­cant­ly bet­ter moods, more pos­i­tive emo­tions, more vig­or, and a greater sense of per­son­al restora­tion after­wards than those who gazed at the urban scene.

It may be that some of these ben­e­fits have to do with how forests affect our brains. One study found that peo­ple liv­ing in prox­im­i­ty to trees had bet­ter “amyg­dala integrity”—meaning, a brain struc­ture bet­ter able to han­dle stressors.

These find­ings and many others—including an ear­li­er review of the research—show how even short amounts of time in a for­est can give us a break from our fren­zied lifestyles.

And improve our general health too

Besides help­ing us breathe, being around trees may improve our health in oth­er ways, too.

Stud­ies have shown that spend­ing short amounts of time in forests seems to ben­e­fit our immune sys­tems. Specif­i­cal­ly, one study found that elder­ly patients suf­fer­ing from chron­ic obstruc­tive pul­monary dis­ease expe­ri­enced decreas­es in per­forin and granzyme B expres­sions, as well as decreased pro-inflam­ma­to­ry cytokines—all relat­ed to bet­ter immune function—after they vis­it­ed forests rather than urban areas. Though it’s not clear exact­ly why this would be, a pri­or study sug­gests that trees may improve immu­ni­ty thanks to cer­tain aro­mat­ic com­pounds they release.

Trees also seem to help our heart health. In one study, par­tic­i­pants walked in a for­est one day and an urban envi­ron­ment anoth­er day, and researchers mea­sured how the two walks impact­ed their bod­ies. In com­par­i­son to the urban envi­ron­ment, walk­ing in trees low­ered people’s blood pres­sure, cor­ti­sol lev­els, pulse rates, and sym­pa­thet­ic ner­vous sys­tem activ­i­ty (relat­ed to stress), while increas­ing their parasym­pa­thet­ic ner­vous sys­tem activ­i­ty (relat­ed to relax­ation). All of these phys­i­o­log­i­cal mark­ers are tied to bet­ter heart health, sug­gest­ing that walk­ing in the woods improves car­dio­vas­cu­lar function.

Though it could be that these health ben­e­fits are due less to trees than to nat­ur­al spaces in gen­er­al, New York­ers liv­ing near trees report bet­ter over­all health than res­i­dents liv­ing near green, grassy spaces. And anoth­er study found that women who live in areas affect­ed by tree loss have a high­er risk of car­dio­vas­cu­lar dis­ease than those in unaf­fect­ed areas. One study that tried to quan­ti­fy this health effect con­clud­ed that “hav­ing 10 more trees in a city block, on aver­age, improves health per­cep­tion in ways com­pa­ra­ble to an increase in annu­al per­son­al income of $10,000 and mov­ing to a neigh­bor­hood with $10,000 high­er medi­an income or being 7 years younger.” Clear­ly, there’s some­thing heal­ing about trees.

Trees may make us more generous and trusting

Research sug­gests that nature expe­ri­ences help us to feel kinder toward oth­ers, and many of those stud­ies involve trees.

In one exper­i­ment, researchers asked a group of uni­ver­si­ty stu­dents to look up at either a tall build­ing or a grove of tow­er­ing euca­lyp­tus trees for one minute. They found that stu­dents who stud­ied the trees expe­ri­enced more feel­ings of awe—a sense of won­der and of being in the pres­ence of some­thing larg­er than one­self. After­wards, when one of the exper­i­menters pre­tend­ed to acci­den­tal­ly drop a bunch of pens, the stu­dents who had seen the trees and felt awe helped pick up more pens than those who had looked at the building.

In anoth­er study, researchers found that peo­ple were more will­ing to help some­one who’d lost a glove if they had just spent time walk­ing through a park with trees, rather than if they were near the entrance to the park. Unfor­tu­nate­ly, this study, like many oth­ers, doesn’t spec­i­fy the ben­e­fits of trees ver­sus green space in gen­er­al. So, we don’t know the exact role trees play in pro­mot­ing kind and help­ful behav­ior. But there’s a good chance that their pres­ence at least con­tributes to bet­ter social interactions.

For all of these rea­sons, I make an almost dai­ly prac­tice of inter­act­ing with trees. Whether it’s just look­ing out my office win­dow or tak­ing a short stroll down the block to vis­it a favorite oak, I like to acknowl­edge the trees around me, often with a quick pat or hug. As research con­tin­ues to grow, I’m sure my tree appre­ci­a­tion will, too.

— Jill Sut­tie, Psy.D., is Greater Good‘s  book review edi­tor and a fre­quent con­trib­u­tor to the mag­a­zine. Based at UC-Berke­ley, Greater Good high­lights ground break­ing sci­en­tif­ic research into the roots of com­pas­sion and altru­ism. Copy­right Greater Good.

The Study:

Psy­cho­log­i­cal Ben­e­fits of Walk­ing through For­est Areas

• Abstract: This study aimed to clar­i­fy the psy­cho­log­i­cal ben­e­fits of brief walks through for­est areas. In addi­tion, we aimed to exam­ine the asso­ci­a­tions between psy­cho­log­i­cal respons­es and trait anx­i­ety lev­els. Five-hun­dred-and-eighty-five par­tic­i­pants (mean age, 21.7 ± 1.6 years) were instruct­ed to walk pre­de­ter­mined cours­es through for­est (test) and city (con­trol) areas for 15 min. The Pro­file of Mood State (POMS) ques­tion­naire and State-Trait Anx­i­ety Inven­to­ry were used to assess par­tic­i­pants’ psy­cho­log­i­cal respons­es and trait anx­i­ety lev­els, respec­tive­ly. The results revealed that walk­ing through for­est areas decreased the neg­a­tive moods of “depres­sion-dejec­tion”, “ten­sion-anx­i­ety”, “anger-hos­til­i­ty”, “fatigue”, and “con­fu­sion” and improved the par­tic­i­pants’ pos­i­tive mood of “vig­or” com­pared with walk­ing through city areas. Fur­ther­more, a sig­nif­i­cant cor­re­la­tion was found between par­tic­i­pants’ trait anx­i­ety lev­els and their changes in the sub­scale of “depres­sion-dejec­tion” of POMS after walk­ing through for­est areas. A more effec­tive reduc­tion in the feel­ing of “depres­sion-dejec­tion” after walk­ing through for­est areas was observed for par­tic­i­pants with high trait anx­i­ety lev­els than for those with nor­mal and low trait anx­i­ety lev­els. This study showed the psy­cho­log­i­cal ben­e­fits of walk­ing through for­est areas and iden­ti­fied a sig­nif­i­cant cor­re­la­tion between psy­cho­log­i­cal respons­es to walk­ing through forests and trait anx­i­ety levels.

Related article:

• New book on how “For­est Bathing” can pro­mote phys­i­cal and men­tal health