ferns and orchids and bromeliads and strung with lianas. In some spots,
the vegetation was so thick that soil mats had formed above the ground,
and these had sprouted plants of their own—forests in the air. With nearly
every available patch of light and bit of space occupied, the competition
for resources was evidently fierce, and it almost seemed possible to watch
natural selection in action, “daily and hourly” scrutinizing “every
variation, even the slightest.” (Another theory of why the tropics are so
diverse is that greater competition has pushed species to become more
specialized, and more specialists can coexist in the same amount of
space.) I could hear birds calling, but only rarely could I spot them; it was
difficult to see the animals for the trees.
The view from Plot 4.
Somewhere around Plot 3, elevation 9,680 feet, Silman pulled out the
shopping bag full of coca leaves. He and his students were carrying what
seemed to me to be a ridiculous amount of heavy stuff: a bag of apples, a
bag of oranges, a seven-hundred-page bird book, a nine-hundred-page
plant book, an iPad, bottles of benzene, a can of spray paint, a wheel of
cheese, a bottle of rum. Coca, Silman told me, made a heavy pack feel