For much of the last half-century, archeologists have viewed the South American rain forest as a ''counterfeit paradise" whose inhospitable environment precluded the development of complex societies. But new research suggests that prehistoric people found ways to overcome the jungle's natural limitations and thrive in large numbers. The secret, say the theory's proponents, is in the ground beneath their feet. The highly fertile soil called 'terra preta do indio', Portuguese for Indian black earth, was either intentionally created by these pre-Columbian people or is the accidental byproduct of their presence.
     ''It's made by pre-Columbian Indians and it's still fertile," said Bruno Glaser, a soil chemist from the University of Bayreuth in Germany who took samples of terra preta recently near the jungle town of Iranduba (Brazil). This specially modified soil is scattered across millions of acres in the Amazon rain forest, in some areas comprising 10 percent of the ground area. And it is typically packed with potsherds and other signs of human habitation.
     ''We believe there weren't just tribal societies here, but rather complex chiefdoms, and we're providing the proof," said James B. Petersen, an archeologist from the University of Vermont. His team of archeologists have excavated more than 60 sites rich in terra preta near the jungle city of Manaus. On some of the sites, several square miles of earth are packed with millions of potsherds. The archeologists also cite evidence of giant plazas, bridges and roads, complete with curbs, and defensive ditches that would have taken armies of workers to construct. The earliest signs of large, sedentary populations appear to coincide with the beginnings of terra preta. ''Something happened 2,500 years ago, and we don't know what," said Eduardo Neves, a Brazilian archeologist at the Federal University of Sao Paulo.
     The research into terra preta fuels a ''revisionist school" of scientists who argue that the pre-Columbian Amazon was not a pristine wilderness, but a heavily managed forest teeming with human beings. They theorize that advanced societies existed in the region from before the time of Christ until a century after the European conquest in the 1500s decimated Amerindian populations through exploitation and disease. But not everyone working in Amazonian research buys the new theory. ''The idea that the indigenous population has secrets that we don't know about is not supported by anything except wishful thinking and the myth of El Dorado," said archeologist Betty J. Meggers, who is the main defender of the idea that only small, tribal societies ever inhabited the Amazon. ''This myth just keeps going on and on and on. It's amazing."

Source: The Boston Globe (4 January 2005)