IRANTXE RESERVE, Brazil -- The canoe floated across a current so clear that each pebble shimmered in the riverbed beneath. Farther downstream, the river plunged over a sheer waterfall, where a rainbow arched in the mist. The five Irantxe tribesmen landed their vessel and followed a trail through a dense stand of jatoba trees.
When they emerged after 50 yards, the landscape no longer looked anything like the southern edge of the
It looked like Iowa.
Corn and soybean fields extended to the horizon. Seven green John Deere combines were parked near a farmhouse.
''If we were an aggressive tribe, we would have killed the landowners already," said Tupxi, one of the canoeists, who estimated his age at 77. ''But we're peaceful, and we don't want to fight. So all of this has been lost."
The tribe's reserve is a forested island surrounded by thoroughly conquered farmland. It sits in the middle of Mato Grosso, a state whose booming agricultural sector has helped Brazil challenge the US position as the world's top exporter of soybeans and beef.
In the process, however, Mato Grosso has become the capital of Amazon deforestation. Much of the forest has been cut down, often illegally, and turned into grazing pastures and soy fields. The state's governor, Blairo Maggi, owns the world's largest soy exporting company.
In 2004, Amazon tree-cutting reached its highest level in a decade: More than 10,000 square miles, an area roughly the size of Massachusetts, were cut down, according to government statistics released earlier this month. Mato Grosso, one of five Amazonian states, accounted for 48 percent of the overall deforestation.
Environmental groups slammed authorities for lax regulation and accused Maggi of sacrificing natural treasures for agricultural wealth.
The government recently announced the arrest of 89 members of a large illegal logging ring, half of whom were employees of the agency responsible for enforcing logging regulations. Maggi's environmental secretary was arrested on charges of helping loggers bypass regulations. Maggi fired him and promised to crack down on illegal logging.
But the measures did not placate tribes such as the Irantxe, whose members said their rain forest culture has been toppled by buzz saws.
''It is all about money," said tribesman Napuli, 31. ''If they try to keep land for tribes like us, they would lose the money they would make on farming."
The members of a government expedition peered through the trees at a partly subterranean dwelling of mud and sticks. They had walked five hours through the Amazon jungle in the state of Rondonia to find the last member of an isolated tribe. Six previous attempts to contact him were unsuccessful. Two members decided to get a closer look. If the man was inside, they would signal that they were friendly and then warn him that if he strayed too far, he might encounter farmers and jungle-clearing machines. A lopsided confrontation, they feared, might result in his death and his tribe's extinction.
One of the men approached the hut but suddenly turned and sprinted away -- with an arrow in his chest, recounted Orlando Possuelo, 20, a surveyor with the government agency responsible for protecting Amazonian tribes.
''The Indian shot an arrow at him through the opening. It hit him in the chest, but it was above the heart," Possuelo said. ''We all started running, even the guy who was shot. He pulled the arrow out while he ran."
Possuelo's father, Sydney, a prominent Amazon expeditionist who heads the federal tribal protection agency, noted that if the sole tribesman in his remote Rondonia hut were to die, the entire surrounding area could be legally opened up to farming.
''When it comes to protecting the Amazon," he said, ''the government is getting progressively worse."
Two years ago, environmentalists had cheered when longtime rain forest advocate Marina Silva was named to head the environment ministry. Silva helped enact protective measures that made almost 20 million acres of Amazon land off-limits to developers. Her agency placed protections on another 20 million acres surrounding a road project through the forest, and bolstered monitoring activities that doubled illegal-logging arrests in a year.
But the new deforestation figures dealt a disheartening blow. In an interview in Brasilia, the capital, Silva maintained that not enough time had passed since the new protections to show statistical results.
Maggi declined to be interviewed, but a statement provided by his office defended Mato Grosso's efforts against deforestation, including tougher licensing requirements on rural lands and stricter enforcement. In 2004, it said, the state registered 755 infringements and issued fines totaling $30 million.
Soon after he was elected governor in 2002, Maggi announced a goal of boosting the state's soy production to 100 million tons annually. His business, Grupo Maggi, boasts yearly exports of $430 million.
In a 2003 interview, Maggi said environmentalists were exaggerating deforestation problems and threatening the Brazilian economy. ''Behind the environmental concerns are economic interests," he said. ''They are trying to impede or slow the growth of Brazilian production."