Large-scale clearing for agriculture in the Brazilian Amazon.
(Photo courtesy of Jacques Descloitres, MODIS Rapid Response Team, NASA/GSFC)
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COMMERCIAL AGRICULTURE
Agricultural use of some rainforest land proves to be a failure because of the nutrient-deficient, acidic soils of these forests. Nevertheless, many commercial agricultural projects are still carried out on rainforest lands,
although many of these revert to cattle pasture after soils are depleted. Some floodplain regions, like
those of the lower Amazon (várzea), are more suitable for commercial agriculture because annual floods replenish
nutrient stores.
Generally forest clearers use slash-and-burn techniques to clear land, but on a much larger scale
than traditional practices. Instead of burning a mere 2-10 acres (1-4 ha), agriculturalists burn hundreds to thousands
of hectares. This slash-and-burn technique is generally wasteful since it is only occasionally that trees with timber value are removed before the forest is clear cut and left to dry. Following cutting, the area is burned to release nutrients locked up in vegetation and produce a layer of nutrient-rich material above the poor soils of the former tropical forest. The cleared area is quickly planted and supports vigorous growth for a few years, after which the
nutrient stock is depleted and copious amounts of fertilizer are required to keep the operation viable. Fertilizer may be washed into local streams, affecting fish and aquatic life. When the use of fertilizer is deemed no longer efficient, the land is abandoned and allowed to
revert to scrub. Drought-resistant grasses may move in or cattle ranchers may plant imported African grasses for
cattle grazing. The land is now only marginally productive and a limited number of cattle can subsist in the area.
When the land is suitable for agriculture, generally large single cash crops like rice, citrus fruits, oil palms, coffee,
coca, opium, tea, soybeans, cacao, rubber, and bananas are cultivated. Some of these crops are better adapted to
such conditions and last longer on cleared forest lands. However, there are several problems with this type of monoculture
(single crop plantations) in the tropics, besides the loss of forest. First, such planting of a single crop makes
the crop highly vulnerable to disease and pests, as periodic infestations have shown in Brazil, India, and other
places. In natural rainforest, widespread infestations are rare because individuals of a given species are widely
dispersed. Second, the planting of monocultures can be economically risky with the price fluctuations so common in international commodities markets.
Additionally, a single cold spell or drought
can devastate a tremendous part of the agricultural economy.
In the state of Acre in western Brazil, farms and pastures are surrounded by large, undisturbed areas of Amazon rainforest. Since January 2005, many areas in the state have been experiencing severe drought, and the forests have become tinder dry. Since August, agricultural fires—many of them ignited in violation of a state-declared ban—have been escaping control, racing through adjacent fields and spreading into the forests. The situation deteriorated through September, and record amounts of previously undamaged rainforest may burn before the episode is over. Several NASA-funded scientists have helped the Brazilians respond to the disaster by providing daily summaries of fire detections made by satellite, aircraft, and ground observations.
These images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite show a pattern of forest and farmland east of the city of Rio Branco before (top) and after (bottom) the peak of the 2005 agricultural burning season. The images are made from visible, shortwave, and near-infrared light detected by MODIS. Bright green is unburned forest, bright red is recently burned areas, and tan is cleared, but unburned land. Next to some burned fields, the forest appears dark green, or "bruised," probably indicating places where fires escaped from fields and burned into the forest understory.
NASA images by Jesse Allen (NASA Earth Observatory) and Jeff Schmaltz (MODIS Rapid Response), text courtesy of NASA's Earth Observatory.
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The cultivation of some of these crops in mountainous, watershed areas has adverse effects for the environment,
notably the alteration of water cycles and erosion. In Peru, the cultivation of coca plants (containing the basic
ingredient for cocaine) was so widespread in the Andean foothills during the 1980s and 1990s that Peruvian river flood cycles were altered
in some areas, making the high-water season unpredictable. The most serious environmental
concern (other than deforestation) stemming from the cultivation of coca is the dumping of chemicals (including
kerosene, sulfuric acid, acetone, and carbide) used to process coca leaves. However, stopping coca cultivation is
nearly impossible due to simple economics: no crop outperforms coca. The CIA claims that some 600,000 hectares of forest are cleared annually for coca and opium
poppy cultivation.
In some parts of the world, large-scale commercial agriculture takes up the majority of the productive floodplain and volcanic soils, while leaving smaller farmers little choice but to cut farmland from the rainforest. The ownership of these large commercial
farms is concentrated in the hands of a wealthy minority, who may benefit from tax incentives to leave some of their
land fallow and not fully employed at any given time. These large farm businesses generally do not employ large numbers of locals, though when they do, workers are
used seasonally for low wages. In recent years, grain production in Brazil and other Latin American countries has widely accelerated. However, most of the money ends up in the hands of a few large landowners who, in more marginal areas, have relied on subsidies to survive the harsh soil and climate conditions. Only through these handouts have these landowners been able to turn a profit.
Soy
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Soybean cultivation in South America. Map showing soybean distribution area in South America as of the year 2000. Rainforest and savanna ("cerrado") ecosystems in the Amazon are giving way to soya fields. Images courtesy of the Global Land Use Database at the University of Wisconsin.
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Soybeans have become one of the Brazil's most important crops in the Amazon, as well as in the nearby cerrado grassland ecosystem. Today soybeans are flourishing—since 1998, Brazil has added 30 million acres of soybeans, and American firms are aggressively expanding their presence in the Brazilian agricultural sector. Brazil will likely soon supplant the United States as the world's leading exporter of soybeans, at the expense of the forests and savannas of the Amazon basin.
Annual deforestation rates and annual soy expansion for states in the Brazilian Amazon 1990-2005. Note that the 1995-1996 and 1998-1999 years were negative and do not show up on the chart. Graphs based on Brazilian government data.
Total deforestation and area of soybean cultivation across states in the Brazilian Amazon. Overall soybean cultivation makes up only a small portion of deforestation, though its role is accelerating. Further, soybean expansion and the associated infrastructure development and farmer displacement is driving deforestation by other actors.
Note: some soybean farms are established on already degraded rainforest lands and neighboring cerrado ecosystems. Therefore it would be inappropriate to assume the area of soybean planting represents its actual role in deforestation.
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More on soybeans in the Amazon
As Amazon deforestation falls, food production rises
(01/09/2012) A sharp drop in deforestation has been accompanied by an increase in food production in the Brazilian state of Mato Grosso, reports a new study published in the journal Proceedings of the National Academy of Science. The research argues that policy interventions, combined with pressure from environmental groups, have encouraged agricultural expansion in already-deforested areas, rather than driving new forest clearing.
Soy moratorium in Amazon maintaining its effectiveness
(10/14/2011) The moratorium on clearing Amazon rainforest for soy farms in Brazil appears to be maintaining its effectiveness for a fifth straight year, reports the Brazilian Association of Vegetable Oil Industries (ABIOVE).
Despite moratorium, soy still contributes indirectly to Amazon deforestation
(07/15/2011) Soy expansion in areas neighboring the Amazon rainforest is contributing to loss of rainforest itself, reports a new study published in Environmental Research Letters.
Brazilian senator: Forest Code reform necessary to grow farm sector
(07/06/2011) Over the past twenty years Brazil has emerged as an agricultural superpower: today it is the largest exporter beef, sugar, coffee, and orange juice, and the second largest producer of soybeans. While much of this growth has been fueled by a sharp increase in productivity resulting from improved breeding stock and technological innovation, Brazil has benefited from large expanses of available land in the Amazon and the cerrado, a grassland ecosystem. But agricultural growth in Brazil has always been limited — at least on paper — by its environmental laws. Under the country's Forest Code, landowners in the Amazon must keep 80 percent of their land forested.
Profit, not poverty, increasingly the cause of deforestation
(06/13/2011) A new report highlights the increasing role commodity production and trade play in driving tropical deforestation.
More news on soy in the Amazon
Palm oil
The palm oil industry is an increasingly important driver of forest conversion in southeast Asia, especially Indonesia and Malaysia. Cultivation of oil palm, the world's most productive oil seed, has expanded in Indonesia from 600,000 hectares in 1985 to more than 6 million hectares by early 2007, and is expected to reach 10 million hectares by 2010. In Sabah and Sarawak (Malaysian Borneo), the area of plantations has increased from 186,744 hectares in Sabah and Sarawak in 1984 to 1,673,721 hectares at the close of 2003. Scientists say the use of palm oil biodiesel from plantations established on peat soils releases 8 to 21 times the emissions as conventional diesel fuel.
More on palm oil
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Chart showing annual palm oil production by Malaysia and Indonesia from 1964-2006. Click to enlarge.
Forest cover versus palm oil production in Indonesia.
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Girl Scouts activists win forest heroes award for challenging organization on sustainability
(02/10/2012) The United Nations on Thursday honored five 'Forest Heroes' for their contributions toward protecting forests.
More big companies disclosing impacts on forests
(02/07/2012) More companies are reporting on the impact of their operations on global forests, finds a new report. Eighty-seven global corporations disclosed their "forest footprint" in 2011, according to the third Forest Footprint Disclosure (FFD), which asks companies to report on their impact on forests based on their use of five commodities: soy, palm oil, timber and pulp, cattle, and biofuels. This is a 11 percent rise from the companies that reported in 2010, including the first reports by companies such as the Walt Disney Company, Tesco UK, and Johnson & Johnson. However a number of so-called "green" companies continue to refuse to disclose, including Patagonia, Stonyfield Farms, and Whole Foods Markets Inc.
Indonesia to create the world's largest palm oil and rubber company
(02/04/2012) The Indonesian government plans to create a massive plantation firm next month when it will combine the assets of state-owned rubber and palm oil companies, reports Reuters.
5 shot in conflict over oil palm plantation in Sumatra
(02/03/2012) Five villagers were shot in Indonesia's Riau Province on the island of Sumatra during a clash in a land dispute over an oil palm plantation, reports The Jakarta Post and Republika.
Environmental news - month in review: setbacks for the palm oil industry, climate outlook darkens
(02/02/2012) Here mongabay.com provides a quick review of forest-related news for January 2012.
More news on palm oil
Sustainable Agriculture in the Rainforest
Review questions:
- How does large-scale agriculture damage the rainforest?
- Why are soybeans generally bad for the Amazon?
- Are palm oil-based biofuels a threat to rainforests?
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Continued: Cattle Pasture
This article was written by Rhett A. Butler [bibliographic citation for this page] and was last updated on the most recent date listed in the column on the right side.
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WEEKLY NEWSLETTER
INTERACT
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Recent news
Humans drove rainforest into savannah in ancient Africa
(02/09/2012) Three thousand years ago (around 1000 BCE) several large sections of the Congo rainforest in central Africa suddenly vanished and became savannah. Scientists have long believed the loss of the forest was due to changes in the climate, however a new study in Science implicates an additional culprit: humans. The study argues that a migration of farmers into the region led to rapid land-use changes from agriculture and iron smelting, eventually causing the collapse of rainforest in places and a rise of grasslands. The study has implications for today as scientists warn that the potent combination of deforestation and climate change could flip parts of the Amazon rainforest as well into savannah.
New book series hopes to inspire research in world's 'hottest biodiversity hotspot'
(01/17/2012) Entomologist Dmitry Telnov hopes his new pet project will inspire and disseminate research about one of the world's last unexplored biogeographical regions: Wallacea and New Guinea. Incredibly rich in biodiversity and still full of unknown species, the region, also known as the Indo-Australian transition, spans many of the tropical islands of the Pacific, including Indonesia's Sulawesi, Komodo and Flores, as well as East Timor—the historically famous "spice islands" of the Moluccan Archipelago—the Solomon Islands, and, of course, New Guinea. Telnov has begun a new book series, entitled Biodiversity, Biogeography and Nature Conservation in Wallacea and New Guinea, that aims to compile and highlight new research in the region, focusing both on biology and conservation. The first volume, currently available, also includes the description of 150 new species.
New frog trumps miniscule fish for title of 'world's smallest vertebrate'
(01/12/2012) How small can you be and still have a spine? Scientists are continually surprised by the answer. Researchers have discovered a new species of frog in Papua New Guinea that is smaller than many insects and dwarfed by a dime. The frog trumps the previously known smallest vertebrate—a tiny fish—by nearly 1 millimeter.
As Amazon deforestation falls, food production rises
(01/09/2012) A sharp drop in deforestation has been accompanied by an increase in food production in the Brazilian state of Mato Grosso, reports a new study published in the journal Proceedings of the National Academy of Science. The research argues that policy interventions, combined with pressure from environmental groups, have encouraged agricultural expansion in already-deforested areas, rather than driving new forest clearing.
Evidence mounts that Maya did themselves in through deforestation
(12/08/2011) Researchers have garnered further evidence for a smoking gun behind the fall of the great Maya civilization: deforestation. At the American Geophysical Union (AGU) conference, climatologist Ben Cook presented recent research showing how the destruction of rainforests by the Mayan ultimately led to declines in precipitation and possibly civilization-rocking droughts. While the idea that the Maya may have committed ecological-suicide through deforestation has been widely discussed, including in Jared Diamond's popular book Collapse, Cook's findings add greater weight to the theory.
More news on rainforest agriculture
More rainforest news
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