Ssm Winter 2007 Ethpol Brazil Amazon

ethics + policy

the uncertain fate of the brazilian amazon How selective logging impacts the sustainability of rainforests by Julia Guth

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ntil recently, the timber industry and conservationists struck a compromise with selective logging—a process that removes certain trees from specific locations in the forest, as opposed to deforestation, the clear-cutting of large regions. Most scientists and environmentalists believed this process was sustainable and not particularly harmful to forests. However, research led by Dr. Greg Asner, a scientist at the Carnegie Institution of Washington and assistant professor, by courtesy, in Stanford’s Department of Geological and Environmental Sciences, used advanced satellite imaging to prove that selective logging does, in fact, destroy regions of rainforest in the Brazilian Amazon by acting as a catalyst for large-scale deforestation.

The probability that an area will be deforested once the land has been selectively logged has been proven to be 32% within 4 years. A Sharper Eye in the Sky

The largest remaining tropical forest in the world, the Amazon rainforest is as large as the continental United States. It is home to nearly 10% of the world’s mammals and 15% of the world’s known land-based plant species.

Photo Credit: Don Deering, NASA/LBA Project

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Asner is part of the international initiative “Large Scale BiosphereAtmosphere Experiment in Amazonia” (LBA), a Brazil-led project that began in 1997 to study the Amazon Rainforest its deforestation. Selective logging seemed sustainable compared to the large-scale clear-cutting that resulted from the creation of cattle pastures, the primary reason for deforestation. However, before Asner and his crew at the Carnegie Institution began their research in 1999, there had been no studies documenting the regional impacts of selective logging on the rainforest. With their new developments in satellite monitoring technology, Asner’s team revealed the startling truth about selective logging and its not-sosustainable implications.

Measuring Deforestation The use of satellites and aircraft to measure and map the changes in forest canopy, the uppermost layer of branches, is called remote sensing. This method has been historically used to study changes in the Amazon due to large-scale deforestation. Asner and his crew have advanced this technology to map out the effects of selective logging in the Brazilian Amazon. They developed a high-resolution, automated remote-sensing analysis called the Carnegie Landsat Analysis System (CLAS). CLAS is capable of detecting finer changes in the forest and was used to quantify the amount of selective logging in the top five timber-producing states of the Brazilian Amazon.

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Credit: Proceedings of the National Academy of Sciences of the United States of the America (PNAS), 22 Aug 2006

ethics + policy

This image depicts the annual logging intensity throughout a four-state region of the Brazilian Amazon. Gray areas indicate federal conservation lands and indigenous reserves, while the blue areas indicate deforestation.

Future Plans for Research

Selective Logging Leads to Clear-Cutting The results of Asner’s research shows that a large amount of selective logging has taken place in the Brazilian Amazon. Logged areas ranged from 12,075 to 19,823 square kilometers per year between 1999 and 2002. Even conservation lands suffered from 1,200 square kilometers of logged land per year. Furthermore, the study demonstrates that selective logging is far from sustainable. “High-damage logging is in fact occurring,” said Asner. From 1999 to 2004, at least 76% of the more than 2 million square kilometers of the Brazilian Rainforest was harvested, causing enormous damage to the canopy and leaving forests vulnerable to drought and fire. Perhaps the most dramatic finding in this research is the close correlation between selective logging and large-scale deforestation. Because both selective logging and clearcutting rely on roads to access the trees, it was expected that there would be a correlation between the two. The probability that an area will be deforested once the land has been selectively logged was calculated to be 32% within four years. Asner concludes, “Logging that is supported by conservation may be unintentionally supporting clear-cutting.” How does this happen? The link is not clearly established, but there is a correlation between selective logging and clear-cutting, since they occur sequentially in the same area. One possibility is that roads leading to the areas of selective logging open up the patch to clear-cutting by providing easier transportation and access to those trees. Another possibility is that the logging may be causing root damage that negatively affects the surrounding trees and plants. Alternatively, selective loggers may be taking more trees than they should, or completely ignoring the selective logging laws.

A Rainforest Worth Preserving The effects of deforestation extend beyond the immediate threat to biodiversity caused by the destruction of habitats

layout design: layout design: Annie Lee

Photo Credit: Rhett A. Butler / mongabay.com

Massive clear-cutting destroys habitat and increases the risk of fire and drought.

Once the Brazilian Amazon study is completed in 12 months, Asner and his crew plan on analyzing the same effect of selective logging in Peru, Southeast Asia, and parts of Africa. Asner also plans to broaden his focus to include biodiversity. His use of “direct biodiversity mapping” can detect chemicals in the forest canopy to determine the biodiversity of specific regions. and ecosystems found only in the Amazon Rainforest. According to Asner, “The Amazon rainforest plays a vital role in regulating the global climate system.” Approximately 0.1 billion metric tons of carbon are released into the atmosphere each year from the extraction of 27 million to 50 million cubic meters of wood. Trees, whose trunks serve as carbon sinks, release carbon dioxide into the atmosphere when they are destroyed. This emission contributes greatly to the climate system and global warming. The continued depletion of trees faster than they can be replenished also has grave implications for logging sustainability. In the coming years, humanity may be suffering a scarcity of wood due to rapid deforestation occurring in the heart of the tropics.

Research as a Catalyst for Change So how can we save the rainforest? “Recently, due to the work of many people in Brazil including ourselves, the Brazilian government has decided to develop forest concessions for the Amazon,” Asner states. While this policy may seem anti-environmentalist, regulated logging can actually help preserve the forest by sequestering logging and clear-cutting to distinct locations, preventing the destruction of the entire forest. “I believe that Amazonian forests are destined for human domination in the coming few decades,” says Asner. “The changes I’ve witnessed in the past 10 years alone show that development is extremely rapid. Therefore, laws that serve to manage the ‘working nature’ of the forest are vital to the long-term sustainability of the human enterprise in the Amazon, and to the very existence of the forest into the future.” S JULIA GUTH is a sophomore majoring in Earth Systems, with a minor in Economics. She enjoys reading the newspaper, watching documentaries, and playing softball. To Learn More Visit the Laboratory for Regional Ecological Studies website of Dr. Greg Asner at http://asnerlab.stanford.edu

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