The Man Who Planted Trees, by Jim Robbins, science writer for the New York Times and Scientific American.
at the Nippon Medical School took twelve healthy men, from thirty-five
to fifty-six years of age, out of Tokyo and into the forest. For three
days they followed a regimen: the first day they walked among the trees
for two hours, the second day for four hours, and on day three they
offered blood and urine samples and filled out a questionnaire. They
were sampled a week and a month after the trips as well, and these
results were compared to samples taken after walks on normal working
days in Tokyo, in areas without trees.
the samples taken after the hikes in the forest showed significant
increases in 'natural killer,' or NK cells, which prevent the formation
of tumors; an increase in anticancer proteins in the cells; and a
reduction in the concentration of adrenaline in urine, effects which
lasted a week after the trips. Alpha and beta pinene
(an aerosol released naturally into the air by pine trees) were found
in the air in the forest, but not in the city, and the researchers
(germ-killing aerosols released into the air by the trees) to be the
active ingredient in the health effects. Other studies of people who
have spent time among trees have shown lower concentrations of the
stress chemical cortisol, lower pulse rates, lower blood pressure,
greater parasympathetic nervous system activity, and less sympathetic
activity, which means that people are more relaxed."
Walking among trees makes you feel better. And it also looks like it makes you healthier.