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If you watch Nature documentaries, it's easy to come away with the impression that lush tropical forests

have been largely undisturbed until modern times.

Tropical forests have sort of long been considered to be these pristine

wildernesses that humans haven't really touched until recent industrial

forces have started to invade them and challenge them with 21st century capitalism.

Archaeological scientist Patrick Roberts of the Max Planck Institute for the Science of Human

History.

However, in the last two decades, archaeological data have shown that actually human societies have occupied and modified these environments over many millennia.

Robert says some of the trees alive in tropical forests are up to a thousand years old and they're sort of like time capsules, storing a record

of past human activity in their tree rings, chemistry, and DNA.

So we wanted to see how different existing methods might come together to explore past tree

populations, tree growth, tree ages by looking at the largest witnesses of the changes in human

activity in the tropics, the trees themselves.

For example, indigenous peoples of the Amazon Basin cultivated Brazil nuts for thousands of years.

Robert's colleague Victor Cayetano Andrade

analyzed tree rings to determine the age and growth rates of Brazil nut trees

near the city of Manaus. He found that many trees were established in the late 1600s, but there was a steep drop-off in new

trees around the middle of the 18th century.

As colonial communities came into Manaus and developed the city, they drove indigenous people out, often

...