Deforestation

Deforestation is defined as the complete removal or logging of trees in forested areas. It constitutes a serious threat to human civilization and forest ecosystems because tropical forests especially maintain the structure and function of the Earth system and deliver services from biogeochemical cycling to biotic diversity.

Deforestation contributes to global warming and is one of the major causes of the greenhouse effect. According to the Intergovernmental Panel on Climate Change, deforestation, mainly in tropical areas, accounts for up to 20 percent of the total anthropogenic emissions [Page 101]of carbon, a greenhouse gas that is released during burning and decay. The water cycle is also affected by deforestation. Trees extract groundwater through their roots and release it into the atmosphere; when removed, trees no longer evaporate this water. Deforestation therefore reduces the content of water in the soil, as well as in the atmosphere. Furthermore, soil cohesion is reduced, so that erosion, flooding, and landslides may occur. Deforestation has also, if not most importantly, resulted in reduced biodiversity.

The photograph shows a swath of deforested land in the Amazonian rainforest. Such losses contributed to South America having the second-highest estimated reduction in tropical forests in the 1990s, at 0.4 percent.

Source:http://iStockphoto.com

Forests disappear naturally as a result of climate change, fire, hurricanes, or other disturbances; however, most deforestation has been anthropogenic. Although improperly applied logging, fuel wood collection, fire management, and grazing can lead to unintentional deforestation, most anthropogenic deforestation is deliberate. Many developing economies are converting forests and other natural habitat mainly into agriculture. Shifting cultivation is practiced over large areas of land worldwide, raising concern about the efficacy of its practice. However, the rates of deforestation caused by cultivation practices are disputed: Norman Myers attributes 54 percent to shifting cultivation; meanwhile, Edward Barbier finds that intensification of agriculture in shifting cultivation areas makes up 10 percent of tropical deforestation, and expansion of shifting cultivation into undisturbed forests only 5 percent. Gunther Fischer and Gerhard Heilig estimated that cultivated land will increase over 47 percent by 2050, with about 66 percent of it coming from deforestation and wetland conversion. Tropical forest conversion into pasture is another threat for forests in the tropics.

Logging, infrastructure, and settlement expansion, and to a minor degree mining, are other important direct drivers. Logging may be a direct source of deforestation or an indirect source resulting from logging roads enabling access for farmers into previously unreachable areas of forest to establish agricultural plots and pasture.

As for whether poverty is an important driver, there is no consensus. One argument is that poor people are more likely to clear forest because of the lack of other economic alternatives; the counterargument states that the poor lack financial ability to clear the forest. The claim that population growth drives deforestation is another disputed topic. Helmut Geist and Eric Lambin showed that population increase caused by high fertility rates is a primary driver of deforestation in only 8 percent of cases. The Food and Agriculture Organization states that global deforestation rates are not directly related to the human population growth rate but, rather, are an indicator of the lack of technological [Page 102]advancement and inefficient governance. Corruption, inequitable distribution of wealth and power, and globalization are also drivers of deforestation.

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