Selective logging leads to clear-cutting in the Amazon rainforest
Selective logging leads to clear-cutting in the Amazon rainforest
July 31, 2006
A new study links selective logging to clear-cutting in the Amazon rainforest. The research is significant because it identifies “an important indicator of rain forest vulnerability to clear-cutting in Brazil.”
Deforestation in the Amazon rainforest of Peru. Photos by Rhett A. Butler.
A team of scientists, led by Greg Asner of the Carnegie Institution’s Department of Global Ecology at Stanford University, found that 16% of selectively logged rainforests were completely cleared within one year and 32% were totally deforested within four years. The researchers also found high correlation between the presence of roads and deforestation, with virtually no selective logging occurring at distances greater than 15 miles from roads.
The findings, published in the July 31, 2006 online early edition of The Proceedings of the National Academy of Sciences (PNAS), come shortly after Brazil announced plans to open up large areas of the Amazon to selective logging. The sustainable logging initiative, which includes the development of a remote sensing system by the Brazilian National Space Research Institute (INPE) and the Brazilian non-governmental organization IMAZON to monitor timber-cutting in the region, could benefit from the latest Carnegie Institution results, say the authors of the study.
The scientists combined high-resolution, remote-sensing techniques with deforestation maps provided by the Brazilian government to measure logging over a 5-year period across an area of 17,760 square miles (46,000 sq km) in four states. The researchers found “that the probability that logged areas will be clear-cut is highly dependent on their distance from major roads,” according to a news release from the Carnegie Institution. “Most of the selective logging is concentrated within 3 miles (5 km) of major roads. While there was no cause and effect relationship between selective logging and clear-cutting for forests within 3 miles of roads, between 3 and 15.5 miles (5-25 km) from roads there was a clear relationship: selective logging blazes the trail for deforestation. Areas with selective logging at these distances are 2 to 4 times more likely to be cleared than intact forests. ”
“The link between selective logging and clear-cutting is a one-two punch. Once a forest is selectively logged, it is likely on the path to destruction,” said Asner.
“The researchers were surprised by the tight relationship between the two land-use activities because different groups are involved—loggers versus ranchers and farmers—and those actors are treated differently by government regulators,” according to a statement from Carnegie.
“Asner’s group puts to rest another important controversy in the science of the Amazon rain forest,” said Daniel Nepstad, a leading Amazon researcher with the Woods Hole Research Center. “First they showed that forest degradation by loggers affects as much forest as clear-cutting for cattle ranching and swidden agriculture. This latest article demonstrates that these two processes are intimately linked—that the thinning begets forest replacement by cattle pastures and swiddens.”
The research has significant implications for land-use policy in the Amazon basin. The scientists also found that federally protected reserves were significantly less disturbed than unprotected areas.
Hidden threat? Logging road under the forest canopy in Peru. Photo by Rhett A. Butler.
“This breakthrough has created a novel system to detect and quantify even fine-scale logging damage from satellite images across the vast Amazon,” added Lisa Curran of the Yale School of Forestry & Environmental Studies. “Through their analyses, Asner’s team uncovered unforeseen synergies of logging, road access, and subsequent deforestation. Their innovative methods have the potential to revolutionize how we monitor logging damage and its effects on land-use worldwide.”
“The new Brazilian timber concession laws for federally protected lands could bring more control over both the high levels of forest damage caused by current logging operations and the loss of selectively logged forest to full deforestation,” concluded Anser.
Research released earlier this month in Science found that Brazil’s Amazon rain forest is being degraded twice as fast as deforestation figures suggest. Selective logging, where only one or two valuable tree species are harvested from an area, is driving the forest degradation. The findings have important implications for “sustainable harvesting” schemes that have been promoted as ecologically-sound alternatives to traditional harvesting techniques.
The Food and Agriculture Organization of the United Nations has issued a response to a study that found selective logging in the Amazon is highly destructive. The research, conducted by scientists from the Carnegie Institution at Stanford University, was published in Science last month. Selective logging is not necessarily destructive and can be done with low impact on the remaining forests, if the proper techniques are applied, FAO said today, in response to a recent study on logging impacts in the Amazon.
Last week Brazilian president Luiz Inacio Lula da Silva announced a plan to allow sustainable logging across 3 percent of the Amazon rain forest. The law is aimed at undermining destructive illegal logging activities—currently responsible for most of the commercial timber extraction in the region—while generating revenue for forest management and protection, and income for rural Brazilians in the region who often must rely on subsistence agriculture or employment on ranches and plantations under sometimes slave-like conditions.
The worst drought ever recorded in the Amazon continues according to an update from The New York Times. The drought has turned rivers into grassy mud flats, killed tens of millions of fish, stranded hundreds of communities, and brought disease and economic despair to the region.
Deforestation in the Amazon rainforest fell 37% for the 2004-2005 year according to Brazilian government figures released today. Between July 2004 and August 2005, 7,298 square miles of rainforest (18,900 square kilometers) — an area almost half the size of Switzerland — were destroyed. Last year the figure was 10,088 square miles (26,129 sq km kilometers) and since 1978 some 211,180 square miles (546,905 sq km) of forest has been lost.
A new study shows that parks and indigenous reserves in the Amazon help slow deforestation. The study, conducted by researchers at the Woods Hole Research Center and the Instituto de Pesquisa Ambiental da Amazonia, analyzed the effectiveness of protected areas against forest clearing using quantitative analysis of satellite data. The study found that deforestation was 1.7 to 20 times higher along the outside versus the inside perimeter of reserves, while fires were 4 to 9 times higher. Indigenous lands also slowed forest clearing in high-deforestation frontier regions.
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