Brazil: Drought Depletes Amazon, Report Shows Rain Forest Disappearing Much More Quickly Than Prior Estimates

Article excerpt

The end of 2005 brought a record-breaking drought to Brazil's Amazon River basin, leading to a state of emergency in several areas. The drought coincided with a new report by scientists who said previous efforts to analyze the depletion of the world's largest rain forest--which did not adequately take selective logging into account--may have significantly underestimated the degree to which logging was affecting the Amazon.

"Selective-logging" analysis reveals 60% underestimate

A team of scientists from Brazil and the US published an October 2005 report in the US journal Science suggesting that deforestation of the Brazilian Amazon had been underestimated by at least 60%. The team found that traditional satellite-image analyses of the rain forest were insufficient. "A detailed comparison of Landsat satellite observations against field measurements of canopy damage after selective logging proved that traditional analytical methods missed about 50% of the canopy damage caused by timber-harvest operations," said their report.

The group employed a more-advanced technique of satellite imaging that could pick up more types of logging activity, including selective logging, where loggers pick out valuable trees but leave surrounding forests intact.

The study looked at five states: Para, Mato Grosso, Rondonia, Roraima, and Acre, which the team said accounted for approximately 90% of all deforestation in the Brazilian Amazon. They said selective logging was concentrated in Mato Grosso and Para, with areas logged that way exceeding or nearly matching deforested areas.

Deforestation in the Amazon has reached such a massive scale that the only way of measuring it is by using satellites. The trouble has been that, while traditional aerial images can show areas that have been completely destroyed, they do not reveal selective logging of valuable trees such as mahogany.

With input from the National Aeronautics and Space Administration (NASA), the joint US-Brazil team used an ultrahigh-resolution technique to examine just how much selective logging was going on. The researchers concluded that the area of rain forest destroyed between 1999 and 2002 was thousands of square kilometers larger than previously thought.

They also found that about 25% more carbon had been released into the atmosphere than estimated--possibly enough to affect climate change. The report conclusion said, "Selective logging doubles previous estimates of the total amount of forest degraded by human activities, a result with potentially far-reaching implications for the ecology of the Amazon forest and the sustainability of the human enterprise in the region."

The businesses conducting such practices claim picking out individual trees is more environmentally friendly than the blanket clearance of huge areas. But environmental campaigners say that, to reach the prized trees, roads have to be built and heavy equipment brought in. This, they say, can be of no benefit to the Amazon.

Government says deforestation down, credits policies

Brazil's government welcomed the report but said the figures were exaggerated. Brazilian officials praised the scientists for highlighting the issue of selective logging but said the new figures were hard to believe. Two months earlier, the government had announced estimates that deforestation in the Amazonian rain forest had fallen by 50% in 2005. The government said it believed this was the result of new protection policies.

Environment Minister Marina da Silva said some 9,000 sq km of forest were felled in 2004, compared with more than 18,000 sq km in 2003. The minister said she believed this drop was the result not only of greater government control but also of more emphasis on sustainable-development projects.

Environmental groups warned that it was too soon to be sure there had been a long-term reversal in the destruction of the world's largest rain forest. …