planted trees only after forests had been
logged—it counted on burned areas regen-
erating naturally. Now, “over 80 percent of
our reforestation needs are being driven by
catastrophic wildfire,” says David Lytle, the
agency’s forest and rangeland management
director. More than half of the millions of acres
burned recently in 154 national forests won’t
grow back without replanting. Even then, on
tens of thousands of acres, seeds may never
take root, Lytle says.
But around the world, more than just drought
and fire are at play. After extreme heat and
drought had weakened mangroves across hun-
dreds of miles of northern Australian coast, an El
Niño event in 2015-16, likely worsened by climate
change, caused a temporary regional drop in sea
level. Eighteen thousand acres of mangroves died
of thirst. In southeastern Brazil, the same El Niño
drove down precipitation, stressing mangroves
along the flat, brown Piraquê-Mirím River. Then,
one June day in 2016, plum-size hail pummeled
this hot landscape for the first time on record, as
60-mile-an-hour gusts blew foliage off trees and
drove trunks sideways across 1,200 acres.
Five years later I visited with Angelo Ber-
nardino, an oceanographer with Federal
University of Espírito Santo. From a boat on
the river, we watched soil around the dead trees
sloughing into the water, ensuring that few if
any mangroves would ever sprout here again.
IF ANY SPECIES COULD WITHSTAND climate shifts,
you might think it’d be giant sequoias, many of
which have stood since the reign of Julius Cae-
sar. Instead, change has come frighteningly fast.
In 2012 the cover story in National Geograph-
ic’s December issue profiled one stunning
specimen in Sequoia National Park. At 247 feet
in height, nearly half that of the Washington Mon-
ument, the President, as the behemoth is called,
was thought to have been a seedling when fewer
people walked Earth than live in modern France.
It held more leaves than there are people in China.
Our story told of sequoias’ remarkable resil-
ience: the way tannins supposedly made them
impervious to wood-boring beetles; how their
thick bark was nearly flame resistant. Research-
ers were wary about the future but not alarmed.
Last summer, less than a decade later, I sat in
the canopy of a nearby sequoia and stared over at
the President. My throat itched from the smoke
of a nearby wildfire. My legs ached from hauling
myself 200 feet up a climbing rope to join forest
ecologist Anthony Ambrose. I’d come because
he and other scientists were suddenly rattled.
In 2014, two summers after that story was
published, sequoias began shedding needles,
a severe move to curb water demand during a
horrendous drought. Then scientists noticed
33 trees succumbing to fatal beetle attacks.
Ambrose saw tunnels carved through bark. He
saw branches trying to push insects out by ooz-
ing pitch. He worried other trees might be next.
Before then, sequoias were considered “freaks”
of the conifer world because “nobody had ever
seen one killed by insects,” Nate Stephenson
had told me the day before I met Ambrose.
Stephenson would know. After studying these
monarchs for more than 40 years, he probably
understands them better than anyone else.
In 2015, shortly after the needles fell and the
bugs arrived, Stephenson met with Christy
Brigham, who’d recently arrived as the park’s
chief of resources. “How bad is it?” she asked.
Stephenson saw no reason for panic.
Drought and fire threats to sequoias had been
predicted by climate modelers, but most didn’t
expect serious danger for decades. Sequoia and
Kings Canyon National Parks had pioneered the
setting of prescribed burns to clear brush and
logs from the understory so that wildfires didn’t
explode. The parks would now light even more
controlled blazes, Brigham decided. She hired
Ambrose and forest ecologist Wendy Baxter to
track how sequoias were managing water stress.
Ambrose has climbed enough sequoias to
know they are tough old beasts. He’s seen them
struck by lightning only to grow new canopy
branches. He’s watched them slow their photo-
synthetic machinery in dry times. Trees that can
drink 800 gallons of water a day don’t survive
thousands of years without learning to “hunker
down,” he says. But by 2021, as we sat together
staring at the President after the most shocking
fire season on record, Ambrose was wondering
how much more these trees could take.
Sequoias need low-intensity ground fires to
release seeds from their cones and clear soil, so
seeds can take root. Their high branches make
them unlikely hosts for canopy fires. But in 2020
our history of suppressing fire collided with a
rapidly changing climate. The same dry spellTHE FUTURE OF FORESTS 67