Deforestation Rate Continues to Plunge in Brazil

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by Antonio Regalado, Science Magazine

The Brazilian government says that a preliminary survey by a low-resolution satellite shows that deforestation in the Amazon declined by 47.5% over the past 12 months. The figure is the largest decline since measurements began in 1988 and, if confirmed by data from a second set of satellites due out later this year, would amount to nearly a 90% drop in lost forest area since a 2004 peak.

“I think the results are pretty strong for a big additional decrease in deforestation,” says Greg Asner, a satellite expert with the Carnegie Institution for Science at Stanford University. “I am really pleased to see it. I do not doubt that the trend is real.”

The Instituto Nacional de Pesquisas Espaciais (INPE), Brazil’s remote-sensing agency, said fires burned 2296 sq km between August 2009 and August 2010. That compares with 4375 sq km for the preceding 12-month period. Clearing was concentrated in the agricultural states of Pará and Mato Grosso. Asner, who uses satellites to monitor tropical forests globally, says Brazil is the only tropical country where deforestation rates are decreasing consistently. Deforestation refers to land cleared by fires for pastures or farms. The satellites do not monitor another activity, illegal logging, that also can degrade forest regions.

The release of the data has political overtones 1 month before the presidential election. Environment Minister Izabella Teixeira called the figures the “lowest of the low” and credited government enforcement efforts, including cutting off loans to deforesters.

Researchers say the data comes with several asterisks. The low-resolution system, known as the Real-time Deforestation Detection System, detects only fires covering more than 25 hectares. Indeed, INPE specialists told the Brazilian press that farmers may now be employing smaller conflagrations to escape detection, and the agency reported a large increase in the number of fires in August.

Daniel Nepstad, a senior scientist who works on tropical forests at the Woods Hole Research Center in Massachusetts, says that recent efforts by large soybean and beef processors not to buy products from newly deforested areas has helped slow the rate of deforestation. Some landholders may also be conserving forests in hope of receiving carbon credits. “I think there has been a very big change in the attitude of ranchers and farmers both for market reasons and due to enforcement,” says Nepstad. “It’s seen as a risky thing to do.”

Scientists, including Nepstad and Asner, note that the global economic slump may also be playing an important role. If beef and soy prices were to rise, they say, it’s unclear whether Brazil could prevent deforestation rates from soaring once again.

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