Deforestation is commonly defined as the destruction of forests due to human activity, typically performed by governments, private firms, and illegal loggers. The environmental, social, and economic consequences of deforestation can be devastating. Three primary methods used by harvesters include clear cutting, selective harvesting, and slash and burn techniques.
Clear cutting, or ‘clearing’, is the most popular and economically profitable method of logging. Clear cutting serves a dual purpose: marketing harvested wood and clearing the land for cattle farmers. The loss of forest cover that accompanies clear cutting leads to habitat destruction, loss of biodiversity, species extinction, soil erosion, flooding, nutrient loss, elimination of indigenous tribes, disruption of weather patterns, and increased climate change (Roberts and Roper 2001).
Slash and Burn
Slash and burn techniques are typically used by civilians in search of land for living and agricultural purposes. The forest is first clear cut, and the remaining material is burned, releasing harmful greenhouse gases into the atmosphere. These emissions have been linked as direct contributors to global warming (Kimmins 1992). One of the driving forces behind this process is a result of overpopulation and subsequent sprawl (Berkmuller 1992). These methods also occur as a result of commercial farming. The lumber is sold for profit, and the land, cleared of all remaining brush and suitable for agricultural development, is sold to farmers.
Selective harvesting is perhaps the most environmentally conscious method of logging. Unlike the aforementioned techniques, this method is used solely for harvesting wood. Logs are selectively harvested around old-growth trees, whose durability and long interconnectedness with the ecosystem provide unique habitats for plants and animals. This method of deforestation is intended to preserve the ecosystem while still reaping the benefits of timber harvesting (Glastra 1999). However, selective harvesting can still cause habitat destruction, fragmentation, and microclimate alteration that can harm the remaining trees and ecosystem (Glastra 1999).
The underlying causes of forest degradation are engrained within the socioeconomic factors of developing nations. Poverty and poor city conditions in conjunction with global population growth give incentive to poor families to migrate illegally into the rainforests of tropical countries and engage in harvesting (Berkmuller 1992). These poorer countries are generally unable to produce alternatives for products that are harvested from forests. As a result, in order to pay national debt or boost economic growth, governments sell valuable forest to logging companies (Berkmuller 1992).
Although slash and burn creates an initial fertile layer of ash, making the soil highly productive for agriculture, this lasts only for a few years (Lindsey 2007). The loss of trees generates widespread erosion, resulting in water pollution from surface runoff, severe flooding, and the depletion of coastal fisheries. The loss of topsoil due to erosion can also be costly in an economic sense. For example, in the Indonesian island of Java, 770 million metric tons of topsoil were eroded in the late 1980’s at a cost of approximately 1.5 million tons of rice, or enough to satiate the needs of almost 15 million people (Mongabay 2007).
Disruption of water absorption, increased soil erosion, and species loss all pose a threat to global forest ecosystems. This causes biodiversity loss through habitat destruction, the disruption of global weather patterns. The reduction of carbon sinks around the world contributes to climate change, threatening the health of the global environment. As less carbon dioxide is absorbed by forests and more is released from the burning of their remains, greenhouse gas concentration in the atmosphere increases (Schulze et. al 2000). If the current global exploitation of forest resources and degradation of forest land is allowed to increase in generations to come, the worldâ€™s forests will become unable to produce the vital services it provides today.
Berkmuller, Klaus. Environmental Education about the Rain Forest. The World Conservation Union, Cambridge, UK, 1992.
Glastra, Rob. Cut and Run: Illegal Logging and Timber Trade in the Tropics. International Development Research Centre, Ottawa, Canada, 1999.
Kimmins, Hamish. Balancing Act: Environmental Issues in Forestry. University of British Columbia Press, Vancouver, Canada, 1992.
Lindsey, Rebecca. “Tropical Deforestation.” Earth Observatory. NASA. 30 March 2007.http://earthobservatory.nasa.gov/Library/Deforestation/printall.php. (accessed 10 December 2007).
Mongobay. “Erosion and It’s Effects.” Tropical Rainforests. http://rainforests.mongabay.com/0903.htm. (accessed 10 December 2007).
Roberts, Ralph W. and John Roper. “An International Forestry Organization: Do We Need One?” The Forestry Chronicle 77, no. 6 (2001): 982-84.
Schulze, Ernst-Detlef, Christian Wirth, and Martin Heimann. 2000. “Climate Change: Managing Forests After Kyoto.” Science Magazine 289, no. 5487 (2000): 2058-59.