Human Threats to Rainforests—Subsistence Activities

Imperiled Riches—Threatened Rainforests

SUBSISTENCE ACTIVITIES

At least 60 percent of tropical deforestation is caused by subsistence activities on a local level by people who simply use the rainforest's resources for their survival. Having neither the money nor the political power to acquire holdings on productive lands, these transient settlers follow and settle along roads constructed in the rainforest by development or extractive firms. After cutting trees for building material, these people use the slash-and-burn technique to clear the surrounding forest for short-term agriculture. First, understory shrubbery is cleared and then forest trees not used as construction material. The area is left to dry for a few months and is then burned. The land is planted with crops like bananas, palms, manioc, maize, or rice. After a year or two, the productivity of the soil declines, and the transient farmers press a little deeper and clear additional forest for more short-term agricultural land. The old, now infertile fields are left for waste or sometimes used for small-scale cattle grazing.

Rondônia, Brazil. Top: June 1985, Bottom: August 1992

These photographs, showing the destruction of tropical rain forests, provide a visual indication of the rate of deforestation that is taking place in the state of Rondônia, which has been especially hard hit by deforestation. The amount of clear-cut area now exceeds the area of remaining rainforest timber stands. The solid dark green areas show the remaining tropical rainforest canopy. Two urban areas separated by a small river can be seen near the center of the photograph.

Photos and text are courtesy of the Image Science and Analysis Laboratory, NASA-Johnson Space Center.

Although this sort of slash-and-burn agriculture has been used for centuries by indigenous peoples, the practice has been carried out in a careful, small-scale, rotational manner, which ensures relative sustainability. In the past the clearing was left idle for 20 to 100 years, so the forest could recover and again provide fertile land and useful timber. The situation is different today. So many people are practicing slash-and-burn agriculture in a non-rotational manner that fields do not have time to return to secondary forest as they do after natural disturbances. The clearing cycles are becoming shorter and shorter, and in some cases it is only 5-8 years before the forest scrub is again cleared. Eventually, the rainforest ecosystem fails and is replaced by tough grasses which can tolerate the short cycles.

The colonizer not only brings his fire to the rainforest, but also his domestic animals and diseases. Domestic animals decimate local wildlife by infecting them with disease and eating their young, while local indigenous peoples, where they exist, can be infected by the colonists' diseases. When not actively burning forest for agricultural clearing, the colonizer cuts fuel wood and hunts wildlife for food.

It is not solely the fault of the landless peasants for their plight; the unequal distribution of land and inability of the government to provide sufficient legal mechanisms for them to gain title to land are also to blame. These people have few options, and without a better alternative they will continue to do what they must to survive: destroy the forest. This subsistence activity on a local level is the greatest threat to the future of the rainforest and the most difficult to address, especially in regions with fast-growing populations.

The International Fund for Agricultural Development estimates that 10 million hectares of tropical forest are temporarily cleared every year for shifting agriculture. For comparison, FAO says that about 10.4 million hectares of tropical forest were permanently deforested each year between 2000 and 2005.

In some countries, the colonization of rainforest land is encouraged by developing governments who would rather have people living on their own land, creating GDP, than in the slums of the crowded cities, consuming GDP. Many governments lack the resources and foresight necessary for proper urban planning and employment. Thus laws are passed by legislatures that promote the clearing of primary forest by allowing free ownership of such lands. In Peru and other countries, for unoccupied or unused land that has been settled or cultivated for a specified amount of time, the land rights revert to the settler regardless of the previous owner (in some cases even if it was a reserve or national park).

The governments of other countries like Brazil and Ecuador encourage settlement of the Amazon Basin by opening roads and offering tax incentives to settlers. Indonesia has a huge resettlement program in the outer islands of the country (Irian Jaya, Sulawesi, Kalimantan, Sumatra) to alleviate some of the population pressures of the central islands, develop new regions for economic growth, and to establish regional hegemony over local populations that may harbor ambitions for political autonomy.

Review questions:

What is slash-and-burn agriculture?
Why do colonists and poor farmers destroy the rainforest?

[full photo version]

Continued: Economic Restructuring

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