"Metal tools largely created slash-and-burn agriculture, William M. Denevan, the Wisconsin geographer, told me. "This picture of swidden as this ancient practice by which Indians kept themselves in a timeless balance with Nature--that is mostly or entirely a myth, I think. At least there's no evidence for it, and a fair amount of evidence against it, including the evidence of simple logic." Slash-and-burn, supposedly a quintessentially Amazonian trait, "is a modern intrusion."