Saving the rain forest is a fashionable idea in faraway developed countries in Europe and North America. Preserve this ecological treasure, the story goes, and greenhouse gas emissions will go down, countless species will be saved, and the environment will be in far better shape. Sounds simple enough.

But at the heart of the matter in Brazil -- home to 60 percent of the Amazon rain forest -- it is anything but straightforward. Wrapped up in the intensely political debate are not just the environmental stakes, but competing economic claims on the land, an increased demand for the food staples and ethanol raw materials grown there, and a rising dispute over land rights. Thanks to the escalation on all fronts, Brazil's conflict between man and nature has hit fever pitch. A bill waiting on President Luiz Inácio Lula da Silva's desk will grant ownership rights to previously illegal occupiers of vast tracts of land in the Amazon if he signs it into law. Proponents claim that granting property rights will create an incentive for owners to conserve their land; critics worry that sanctioning previous land grabs and deforestation will only breed more of the same.

The question nowadays is not so much whether Brazilians can save the rain forest -- we know they can -- but one that is harder to pin down: Do they really want to?

Much hinges on the answer. The Amazon represents more than half of the planet's remaining rain forests; it is the single largest and most species-rich tract on Earth. Just 1 square km of Amazon rain forest can contain more than 90,000 tons of living plants. The Amazon basin supplies 20 percent of the world's oxygen and nearly one third of its freshwater. The forest also holds 10 percent of the carbon stores in the world's ecosystem, meaning that when acres are destroyed, carbon dioxide is released en masse. Each year, an area of Amazon rain forest about the size of Belgium is cleared and burned. Based on current trends, the forest could shrink 40 percent during the next 20 years -- with dire consequences for global warming.

If the environmental stakes are high, however, the economics of deforestation are equally profound. Twenty million Brazilians live in the Amazon region, one of the poorest parts of the country. Many of these people were encouraged to move there during Brazil's period of military dictatorship in the 1960s, 70s, and 80s. Colonizing the Amazon was a strategic necessity, the junta decided, and settlers would be living evidence that Brazil both occupied and owned the land.

Ironically, ownership is not what the settlers got. Brazil has the second-highest concentration of land ownership in the world: While 47 percent of the country's land is controlled by a mere 1 percent of the population, in Amazonia the inequality is even starker, with 82 percent of Brazil's largest landowners holding estates. Most squatters, meanwhile, have no land rights, or at best, well-faked property deeds. So establishing who owns what is difficult; a study by the NGO Imazon suggests that only 14 percent of privately owned land has a secure title.

Poverty and lack of secure tenure render it nearly impossible for farmers to invest in modern techniques. Instead, they simply clear land by slashing and burning the forest. Loggers and farmers work in tandem, with the former taking the best wood -- often illegally -- and the latter sowing grass to raise cattle. The planted pasture soon becomes overrun with native grass, which is unsuitable for grazing, and so farmers move on and on. They knock down adjoining forest to start again, leaving swaths of unproductive deforested land in their wake. A study in the latest issue of Science described this phenomenon as a development "boom-and-bust" that has failed to bring long-term economic growth or social benefits.

Deforestation is a well-known problem in Brazil and one that President Lula promised to take on when he came to office in 2003. An estimated 20 percent of the Amazon had already been lost by then, and about 10,000 square miles had disappeared in the previous two years alone. The signs initially looked good. The president appointed a strong advocate for conservation, Marina Silva, as his minister for the environment. And by August 2007, Lula's government euphorically announced that the rate of destruction had fallen nearly a third -- a success attributed to a crackdown on illegal logging. The government has jailed 600 people for environmental crimes and also prosecuted the killers of Dorothy Stang, an American nun and environmentalist assassinated in 2005. Lula's government increased the protection given to indigenous people's land rights and faced down protests from some ranchers and farmers.