lighter. It also staved off hunger, alleviated aches and pains, and helped
counter altitude sickness. I had been given little to carry besides my own
gear; still, anything that would lighten my pack seemed worth trying. I
took a handful of leaves and a pinch of baking soda. (Baking soda, or some
other alkaline substance, is necessary for coca to have its pharmaceutical
effect.) The leaves were leathery and tasted like old books. Soon my lips
grew numb, and my aches and pains began to fade. An hour or two later, I
was back for more. (Many times since have I wished for that shopping
bag.)
In the early afternoon, we reached a small, soggy clearing where, I was
informed, we were going to spend the night. This was the edge of Plot 4,
elevation 8,860 feet. Silman and his students had often camped there
before, sometimes for weeks at a stretch. The clearing was strewn with
bromeliads that had been pulled down and gnawed upon. Silman
identified these as the leavings of a spectacled bear. The spectacled bear,
also known as the Andean bear, is South America’s last surviving bear. It
is black or dark brown with beige around its eyes, and it lives mainly off
plants. I hadn’t realized that there were bears in the Andes, and I couldn’t
help thinking of Paddington, arriving in London from “deepest, darkest
Peru.”
EACH of Silman’s seventeen tree plots is two and a half acres, and the
plots are arranged along a ridge a bit like buttons on a cloak. They run
from the top of the ridge all the way down to the Amazon basin, which is
pretty much at sea level. In the plots, someone—Silman or one of his
graduate students—has tagged every single tree over four inches in
diameter. Those trees have been measured, identified by species, and
given a number. Plot 4 has 777 trees over four inches, and these belong to
sixty different species. Silman and his students were preparing to
recensus the plots, a project that was expected to take several months. All
the trees that had already been tagged would have to be remeasured, and
any tree that had shown up or died since the last count would have to be