Monica Turner’s who retired last year from the
U.S. Geological Survey. He’s been trying to alert
people to that danger for two decades now.TURNER HAS A QUICK SMILE, bobbed sandy hair,
and, at 62, a college student’s capacity to stay
upbeat while working nonstop. I spent several
days with her last summer in the John D. Rocke-
feller Jr. Memorial Parkway. The parkway is not
a highway but a parcel of sagebrush and pine
larger than Manhattan. It links Yellowstone and
Grand Teton National Parks. Turner seemed so
at home on this forested plateau that her Long
Island accent kept catching me off guard.
Turner showed up in Yellowstone in 1978 to
work as a summer ranger, giving guided nature
talks at twilight. Yellowstone, with its golden
meadows and kaleidoscopic thermal pools,
transfixed her. She eventually would return and
spend decades studying its trees.
In 1988 Turner and a colleague, ecologist Bill
Romme, crisscrossed its wildlands in a heli-
copter, scanning the aftermath of the park’s
worst fire season in a century. A third of Yellow-
stone—793,880 acres—had gone up in smoke
in a few months. Turner feared it would never
recover. But during that flight she began to
believe what Romme had recently suggested:
This was what Yellowstone was supposed to do.
Many people had assumed Yellowstone’s fires
blew up because firefighters more than a century
earlier had begun suppressing wildfires, allow-
ing excess trees to pack forests like kindling. This
is true in parts of the West. But while traversing
game trails to map the park’s fire history, Romme
discovered that Yellowstone historically burned
very severely once in a great while. “There had
not been very many fires even in the days before
fire suppression,” he told me one morning in the
park. “It was really kind of shocking.”
Yellowstone is lodgepole country. Their thick,
slender trunks occupy 80 percent of the park’s
woods. Some are serotinous, meaning they need
fire to unlock cones that hold their seeds. Romme
had shown that these forests had seen monster
stand-clearing blazes in the 1700s and 1800s.
Such fires were rare because the park was “too
moist, and it was too cool,” he said. But every 100
to 300 years, in an exceptionally hot, dry sum-
mer, enormous patches would ignite in one greatimportant and cannot be replaced quickly—if
ever,” says Nate Stephenson, a scientist emeritus
with the U.S. Geological Survey.
That will matter to us all. Humans are bound
to the woods. Our history is linked to trees. We
climbed down from their canopies and used
them to make fire. The advent of paper—and the
printing press—let literature and science flour-
ish. Trees feed us, shelter us, give us medicine.
We lean on them in ways we scarcely acknowl-
edge, as sources of wonder and inspiration or to
decompress in a noisy world.
One of my favorite escapes is the Hoh Rain-
forest on the Olympic Peninsula, four hours
from my home in Washington State. It’s a place
where glistening ferns tall enough to hide elk
crowd the ground while ancient spruces and
big-leaf maples draped in emerald moss block
the sky. What you can see in such places is com-
plex enough, but humans also are beginning to
appreciate how much is going on out of sight.
Trees in a forest are not isolated individuals;
they share nutrients and data across species in
underground fungal networks. They talk to one
another, passing chemical messages, warning
of pest invasions and other dangers.
Old-growth forests are collaborative, Korena
Mafune, a postdoctoral research fellow at the
University of Washington, told me as we walked
through the Hoh recently. She suspects a diminu-
tive version of this fungal network may even exist
on high branches. She’s found soil beneath moss
growing in the canopy, with tiny trees sprouting
from the living branches of big old ones—“a mini-
forest within a forest,” she says. She worries that
even this ancient place, so much richer than a
tree plantation, could change rapidly if a hot
enough dry spell lasted too long.
Already, snow melting early in Alaska is
depriving yellow cedars of their warming blan-
ket, letting cold snaps freeze their roots and kill-
ing them by the thousands. Heat and drought
sparked by climate change have killed up to 20
percent of trees in Africa’s Sahel, in southwest
Morocco, and in the western U.S. since 1945,
according to the latest IPCC report. Five of the
eight most abundant tree species in the Ameri-
can West have declined significantly just since
2000, mostly from fire and insect infestations.
Lodgepole pines top the list.
“Forests are far more vulnerable in the cli-
mate change era than people think,” says Craig
Allen, a landscape ecologist and collaborator of
THE FUTURE OF FORESTS 51