IN GRADE-SCHOOL science class, we learned
that trees produce the air we breathe. But
the estimated three trillion of them currently
living on Earth do far more than that. They
filter out pollutants, prevent erosion, and
redirect stormwater from overtaxed sewers.
They cool air temperatures; offer shelter from
UV rays; yield fruits, nuts, and medicinal
ingredients; and, according to the UN, pro-
vide homes for more than 80 percent of the
planet’s land-based animals, plants, and
insects. And that’s just a warm-up. More
than half of the drinking water in the United
States is filtered through their roots. In cities,
trees reduce the prevalence of asthma (per
a 2008 Columbia University study) and crime
(from research analyzed by Vibrant Cities
Lab), while encouraging people to socialize
more and increasing real-estate values. And
in Kenya, they’ve helped lift people out of
poverty and starvation.
Trees also make us feel good. We climb
them. We hug them. We stretch out under-
neath their boughs. Their very presence can
foster intimacy and wonder, sensations cap-
tured in the popular Japanese practice of
shinrin-yoku, or forest bathing, which invites
people to disconnect from the wired world,
wander through woods, and breathe deeply.
But the question is: Will future generations
breathe as deeply? Like the oceans, trees
remove carbon from the air, and we currently
lose an estimated 10 billion of them a year to
deforestation in the name of development and
to climate change (increased temperatures,
flooding, and fires). This means that they may
be the secret to reversing global warming, too,
states a study recently released by the Swiss
Federal Institute of Technology. What we have
to do is grow more of them. A lot more. The
institute’s climate-change ecologist Thomas
Crowther and his team calculate that by
planting 1.2 trillion on Earth’s available open
land (an area roughly the size of China and the
U.S. combined), we could rid the atmosphere
of two-thirds of the excess carbon already
produced by human activity.
STANDING TALL
Imagine California without its towering redwood forests,
or New England without sugar maples. Trees do so
much more than offer protection and awe-inspiring beauty:
They’re vital to our health and the earth’s. And yet
billions are felled every year. These organizations are
working hard to reforest the planet—and helping
people plant for the future in their own yards, too.
TEXT BY LISE FUNDERBURG
CHANGE
MAKERS
MARTHA
STEWART
60 NOVEMBER 2019 PHOTOGRAPH BY NGOC MINH NGO
