EXPLORE | THE BIG IDEA
I persevered (see “The ‘Wood-Wide Web,’ Explained,”
on this page).“DO YOU HEAR THUMPING?” I asked nervously.
“Helicopters!” whispered a woman next to me
inside the den. We emerged to see the metal dragon fly
churn over the ridge, men staring from tinted win-
dows. Under the swirl of blades, the cedar matriarch
stood at about 115 feet; her family encircled, as if
telling the story of their origin and protecting her.
This multigenerational grove had survived mil-
lennia of climatic variation, insect infestations, and
windstorms, and had been fed by centuries of salmon
runs. The experiences were encoded in their seeds
and tree rings, and the information passed from
tree to tree through belowground fungal networks.
Defenses that evolved over millions of years helped
these trees withstand temperature extremes and
fend off herbivores. They also enabled this forest to
accumulate as much carbon—580 tons per acre—as
a tropical rainforest. But these defenses, we knew,
were no match for the chain saws.
We ran and slipped across the steep slope to the
small clear-cut carved out of the mountain, where
the helicopter now hovered over a makeshift helipad.
One of the defenders climbed up the platform and
waved his arms as if to repel the aircraft.
The differences in worldviews between the loggers
and the defenders suddenly were clapping like thun-
der. Everyone needed these trees, yet for different
reasons. People pitched against people over an indus-
try that no longer serves most well. Then abruptly the
machine turned and flew down the valley.WE CROSSED THE CLEAR-CUT where the ground was
littered with lettuce lichens that fell with tree crowns,
depriving the forest of crucial nitrogen. On the lifeless
bark of fallen giant trunks, we saw drying speckle-
belly lichens—a species considered vulnerable in
the province—but the laws were too weak to protect
them, even if the loggers had noticed.
Following a faint trail into the trees, we passed
ankle-high largeflower fairybells, western rattlesnake
roots, and little prince’s pines, all species I suspected
were linked into the fungal networks of the old firs
and receiving nutrient subsidies in the deep shade.
The rare plants themselves provided an additional
source of carbon for the fungi.
Old-growth forests like this one store twice as
much carbon as century-old forests and six or moreDefenses that evolved over millions
of years helped these trees withstand
temperature extremes and fend off
herbivores. But these defenses were
no match for the chain saws.When Suzanne Simard began
working in forestry after college,
conventional theory held that trees
were isolated loners engaged in a
cutthroat Darwinian competition for
water, sunlight, and food. Timber
companies planted rows of the most
lucrative species and eradicated
most of the competition—a “plan-
tation” approach that Simard felt
ignored the messy genius of nature,
with its many interwoven species.
In a series of breakthrough exper-
iments conducted while dodging
grizzly bears in western Canada’s
rainforests, Simard discovered that
trees are connected through vast
fungal root systems known as mycor-
rhizal networks. Via this subterranean
pipeline, they share carbon, water,
and nutrients. The fungi extract
sugars from the tree roots that they
can’t produce on their own, and
in return the fungi ferry water and
nutrients to the tree roots and even
farther, from tree to tree.
The journal Nature published
Simard’s revolutionary findings
in 1997, with the cover line “The
wood-wide web.” Though her work
provoked harsh criticism, Simard
persisted, demonstrating how trees
communicate and even cooperate
between species, relaying distress
signals about drought and disease,
and trading minerals through a com-
plex circuitry that she compared to
neural networks in the human brain.
Simard has also identified “mother
trees” that act as hubs for these net-
works. They can recognize their own
offspring and shuttle extra resources
to them. When these elders die,
they “dump” carbon and defense
compounds into the network,
uploading food and information forfuture generations. (^) —KERRY BANKS
THE ‘WOOD-WIDE
WEB,’ EXPLAINED