The Sixth Extinction: An Unnatural History

standing in Plot 8, where we’d come across a strip of blue tape outlining
the plot’s border. Silman suspected that it was the handiwork of
colleagues of his from Oxford. Silman spends a lot of time in Peru—
sometimes months at a stretch—but much of the year he’s not there, and
all sorts of things can happen that he doesn’t know about (and, usually,
doesn’t care for). For instance, on our trip Silman found several wire
baskets that had been suspended in the tree plots to catch seeds. Clearly,
they’d been set up for research purposes, but no one had told him about
them or asked his permission, and so they represented a sort of scientific
piracy. I imagined rogue researchers creeping through the forest like
cocaleros.
In Plot 8, Silman introduced me to another “really interesting” tree,
Alzatea verticillata. Alzatea verticillata is unusual in that it is the only
species in its genus, and even more unusual in that it’s the only species in
its family. It has papery, bright green, oblong leaves and small white
flowers which, according to Silman, smell like burnt sugar when in bloom.
Alzatea verticillata can grow to be very tall, and at this particular elevation
—around fifty-nine hundred feet—it is the dominant canopy tree in the
forest. It is one of those species that seem to be just sitting there
motionless.
Silman’s plots represent another response to Thomas—one that’s
practical rather than theoretical. Trees are obviously a lot less mobile
than, say, trogons—tropical birds common in Manú—or even ticks. But in
a cloud forest, trees structure the ecosystem, much as corals structure a
reef. Certain types of insects depend on certain types of trees, and certain
sorts of birds depend on those insects, and so on up the food chain. The
reverse is also true: animals are critical to the survival of the forest. They
are the pollinators and seed dispersers, and the birds prevent the insects
from taking over. At the very least, Silman’s work suggests, global
warming will restructure ecological communities. Different groups of
trees will respond differently to warming, and so contemporary
associations will break down. New ones will form. In this planet-wide