The Sixth Extinction: An Unnatural History

worth of coca leaves that Silman had bought for the equivalent of about
two dollars.
Standing on the mountaintop, Silman told me that the trail we were
going to take down the following morning was often used by coca
peddlers walking up. The cocaleros carried the leaves from the valleys
where they are grown to high Andean villages of the sort we’d just passed,
and the trail had been used for this purpose since the days of the
conquistadors.
Silman, who teaches at Wake Forest University, calls himself a forest
ecologist, though he also answers to the title tropical ecologist,
community ecologist, or conservation biologist. He began his career
thinking about how forest communities are put together, and whether
they tend to remain stable over time. This led him to look at the ways the
climate in the tropics had changed in the past, which led him, naturally
enough, to look into how it is projected to change in the future. What he
learned inspired him to establish the series of tree plots that we are about
to visit. Each of Silman’s plots—there are seventeen in all—sits at a
different elevation and hence has a different average annual temperature.
In the mega-diverse world of Manú, this means that each plot represents
a slice of a fundamentally different forest community.