Tropical rainforest removal is primarily caused by the need for agricultural land. This trend is on the rise, with sectors of forests becoming spaces of crops in South America. The concern in the region of South America is that the forest will be gone within 250 years (Benhin). Tropical rainforests are being depleted at alarming rates in an attempt to feed the world’s populous: agriculture is noted as accounting for almost 90 percent of all deforestation in the tropics (Benhin). Current estimates by the UN place South America at losing over four million hectares annually (Sample); this reality of landscape change is guaranteed to affect the sustenance of life. The removal of rainforest for farmland creates a precarious tip in the global scale, effects of which are preventable with a sustainable mindset.

Agricultural Landscape

Between 2000 and 2005, over 27.2 million hectares of rainforest was cleared in the tropics to create space for farming; all in an effort to increase agricultural yield from the Earth’s landscape (Sample).  In third world countries: “deforestation acts as a cheaper equivalent to a good dose of fertilizer for increased agricultural production in the near term” (Benhin). The question then lies in the sustainability of this human-created perception: the necessity to convert forested land into harvested areas. Figure 2.3.1 reveals the millions of hectares of rainforest removed for farmland in recent years. The red areas reveal the reduction in forest cover by a half between 2000 and 2005. The image is only an estimate of deforestation, showing where areas of forest have been removed and not replaced. This does not include areas of logging or replanting or general degradation of the South American forests (Sample).

NASA earth observatory states: “The single biggest direct cause of tropical deforestation is conversion to cropland and pasture.” This regards subsistence: where small scale farmers use the land for crops or livestock in an effort to survive on a day to day basis. This action has dominated deforestation in the past but now industrial-scale activities are having a more widespread impact. Cattle ranching and soybean production in the Amazon is contributing to both world markets and the removal of trees (Lindsey). Government policies and subsidies sadly also work to encourage forest loss. Brazil, containing about two thirds of the Amazon’s rainforest, is a prime example of the affect of subsistence farming and government benefits. Its production of soybeans replaces the value of forests with land capable of exporting goods. This monetary gain cannot be sustained in economic terms: though Brazil has a place on the world agriculture markets, it is in a declining relationship with the land. Total opportunity cost is neglected in the pursuit for short-term gain.

Land Conversion

Tropical soils have a limited capacity to store nutrients. Almost all of the soil fertility comes from the natural, overlying, vegetation: in the live plants and the decomposed organic layer on the ground. The wet, warm and shaded nature of the forest is the perfect setting for fungi and bacteria. These organisms almost immediately decompose any fallen or deceased species found on the topsoil, and regenerate it, providing a constant recycling of precious organic compounds. However, unlike preferred farmland, where nutrient filled soil can extend down several feet, tropical topsoil is quite thin. Beneath the layer of fertile soil lies a deep bed of clay. When deforestation takes place for agriculture, and other purposes, the sun quickly dries out and kills the bacteria and fungi. This leaving the farmers a short period of one or two seasons, to plant their crops before harsh rains and hot temperatures erode the topsoil and expose the useless clay. The brief period of growth produces such great results that it is beneficial for these farmers to use the land until it can bear no more and move on to the next deforested spot. In deforesting an area, farmers tend to burn the vegetation ground cover, including trees, in the popular slash-and-burn method. This produces a fertilizing ash layer, but also eliminates the nutrient reservoir and increases the effects of flooding and erosion in the area. The soil eventually becomes unsuitable for farming and is further reduced to pasture land. This lessens the chance of forest recovery, as the land is now also compacted under the hooves of cattle (Lindsey). Figure 2.3.2 (1) shows pasture in what was once an area of forests, in the Amazon.

Deforestation in most areas currently produces favourable yields: aided by the layers of ash from burned vegetation, resulting in the positive relationship between natural biomass and agricultural production (Benhin). However, it is evident that rainforest removal reduces the potential of farmland: as tropical soils reflect the nutrients of their surrounding tree canopies, root structures, decaying ground cover, and living vegetation. The balance between the fragile topsoil and the forest comes crashing down with the removal of the trees; erosion becomes an issue and declining agricultural yields result.

Converting large areas of forest to agriculture affects the water cycle. This process in which water evaporates, or transpires off plants, then condenses into clouds and falls as precipitation, occurs in relative proximity to its location of origin. Almost thirty percent of the rainfall received in the rainforest is moisture which the tropical forests previously recycled into the earth’s atmosphere (Lindsey). Evaporation cools the surface of the Earth just as perspiring reduces body temperature in humans. With this reaction, if deforestation continues at today’s pace, science predicts the tropics will experience future climates that are drier and hotter. Such a change affects not only ecosystems but can be applied to the global scale and balance. Desertification is a threat to any land reacting to natural or human induced vegetation removal. The assisted process that leaves the land deprived of nutrients and cover and through erosion and increased temperatures, deserts result. The tropics turning into a Sahara would devastate the biodiversity, inhabitants and climate, leaving food production to scramble for land elsewhere to meet the need of a growing world population. Forests have utmost value in their upright position, not only as timber and agricultural land providers.

Sustainable Expanse

Estimates place South America at losing 0.4 percent of its tropical rainforests annually (Benhin). Agriculture’s contribution to the world amounts to nourishment through occupied and harvested space. Planting in the rainforest involves removing trees, planting, reaching maximum yield, exhausting the soil, and destroying entire ecosystems. The leftover landscape is barren and unable to support much life. In this way, cost of agriculture in the forests of South America outweighs the return in the long term: “The current situation in which the cheap forest biomass is the primary input in agricultural production in the tropics is not sustainable”  (Benhin).Sustainable is a label worth having, with its expense paid in full for future generations, aiding the health and balance of the globe.

Sustainability, in regards to deforestation by agricultural expansion in South America, lies in the application of the precautionary principle. Precautions towards the effects of tree removal and change in land use include increased research and awareness and government participation. Alternatives to large scale agriculture and timber harvesting include taking the forest at face value: conservatively utilizing its resources but maintaining the vegetation diversity and structure. Shade farming is an encouraged sustainable alternative to clear-cutting and burning. Technologies to improve the way areas are farmed, would work to increase yield, and continue to provide for the growing demand. Sustainable techniques would not equate to an immediate increase in agricultural yield, but guaranteed in the long term. Actions would also result in the preservation of the rainforest; its species and surroundings.

Agricultural development is necessary wherever possible on Earth, especially with projected population growth. However, this does not entitle farmers and governments to act on the ideology of “by whatever means necessary.” With a precautionary mindset, actions include developing sustainable agriculture production. Goals include:
·         Improving economic well-being of inhabitants without risking future needs
·         Utilizing resources in a manner that does not degrade them
·         Using resources to promote equity and social justice
·         Maintaining biological and ecosystem diversity
·         Improving the quality of the environment for the future 

-          Brown