The Disappearing Canopy The Causes © Oxford University Press 2009 What human activities cause tropical deforestation? Agriculture © Oxford University Press 2009 Mining Commercial logging © Oxford University Press 2009 Dam construction What human activities cause deforestation in tropical rainforests? Agriculture Commercial logging Mining Dam construction © Oxford University Press 2009 What are the underlying causes of tropical Tropical People demand rainforests for deforestation? Population growth Population Population increases © Oxford University Press 2009 more provide food, land timber, and resources minerals, for etc. people. Resources Resourcesdemanded demanded ( decrease / increase ) What are the underlying causes of tropical deforestation? Why is population growth high in rainforested countries? This is no official family planning in Brazil As long as child mortality Among Malays, Chinese and Indians because of the influenceremains high, people will lived in Malaysia, Malays tend to of the Roman Catholic continue to have large have more children in the family. Church. families. Their ideal family size is to have more than four children. © Oxford University Press 2009 What are the underlying causes of tropical deforestation? Poverty Many tropical countries have a low level of economic development. The people areofpoor Governments poorand receive little countries do education. not have enough capital for Levels of technology and economic development. productivity is low. These countries are usually heavily in debt. People picking up waste in a landfill in Cambodia (Credit: Ng Kim Hung) © Oxford University Press 2009 What are the underlying causes of tropical deforestation? Provide subsidies to Government policy commercial farmers Encourage migration of people to the rainforests Loose land tenure laws enabling developers to buy land in the rainforest Corruption © Oxford University Press 2009 Improve road network to increase accessibility Local governments are attracted by loans given by international loan agencies for financing projects in exploiting rainforests © Oxford University Press 2009 Agriculture A Shifting cultivation Shifting cultivation is mostly practised by native peoples and landless or poor peasants. Shifting cultivators grow different crops, such as maize, beans, yams, bananas and pineapples. Some grow tree crops such as cocoa and coffee. © Oxford University Press 2009 Agriculture A Shifting cultivation The cultivators clear the site by cutting and burning the trees (Credit: Mark Edwards/Still Pictures) The cultivators abandon the existing plot and move to a new (Credit: Yann Arthus-Bertrand/Corbis) plot of land The cleared plot is cultivated for several years until the soil nutrients are used up © Oxford University Press 2009 Agriculture A Shifting cultivation The carrying capacityof of the Major characteristics land in tropical rainforest is shifting cultivation: low. Therefore, shifting Subsistence, mainly for own cultivation is considered a consumption sustainable practice. small farm size labour intensive staple crop growing Footage showing shifting cultivation in western Africa Please click © Oxford University Press 2009 to browse online Agriculture A Shifting cultivation Rapid growth in population Growing more crops on the same amount of land Why has shifting cultivation become destructive to the More landless peasants tropical rainforest? becoming shifting cultivators in the rainforest also cause more destruction to the rainforest The cultivation cycle is shortened © Oxford University Press 2009 Agriculture A Shifting cultivation The pros: -It may be a suitable way to make use of the harsh environment in the TRF, with the low level of technology. - The labour productivity is relatively high. - The energy output (harvest) is high when compared with the energy input. i.e. a high energy ratio - It causes little environmental damage, providing that the fallow period is long enough (e.g. 20 yrs) © Oxford University Press 2009 Agriculture A Shifting cultivation The cons: -It increases loss of nutrients by burning of biomass, leaching of bases and increased soil erosion. -It degrades the primary forest (the climatic climax) to secondary forest, resulted in lower density, lower height, smaller biomass, lower species diversity and more open structure. -It can only support a very small population size, or the exceeding population pressure may cause long term ecological damages. * Viscous cycle of soil depletion: poor harvest frequent movement shorter cultivation cycle shortened fallow period lower soil fertility … © Oxford University Press 2009 Agriculture B Plantations Tropical rainforests are felled for growing cash crops: Tree crop: rubber, oil palm, cocoa and coffee Arable crop: sugar cane and soybean Coffee plantation in Brazil (Credit: Biosphoto/Gunther Michel/Peter Arnold Inc.) © Oxford University Press 2009 Agriculture B Plantations Location Rubber / oil palm plantation: West Malaysia Coffee plantation: Brazil Cocoa plantation: West Africa & Caribbean areas Banana plantation: Caribbean areas © Oxford University Press 2009 Agriculture B Plantations Major characteristics of plantations: carried out by large corporations monoculture (single crop cultivation) Commercial, exportoriented large farm size cash crop growing (Credit: Fernando Bueno/Getty Images) Soybean plantation in Brazil © Oxford University Press 2009 Agriculture B Plantations Economic development results in a large demand for tropical cash crops. This accelerates the destruction of the tropical rainforest. In recent years, more soybeans have been grown in the rainforest to satisfy the increasing demand for biofuel. (Credit: Fernando Bueno/Getty Images) Soybean plantation in Brazil © Oxford University Press 2009 Agriculture B Plantations Reasons for destruction of the tropical rainforest: -Deliberate introduction & cultivation of economically desired species of tropical / subtropical plants -Causing widespread replacement of the native & natural flora (and fauna), modifications or disturbance of the natural landscape. -Artificial practices e.g. permanent removal of natural vegetation, improvement of drainage and soil, application of chemicals © Oxford University Press 2009 Agriculture C Cattle ranching Tropical rainforests are cleared to provide pastureland for cattle ranching. Major characteristics of cattle ranching in tropical rainforests: commercial extensive large farm size mainly for export Cattle ranching in Brazil (Credit: Mark Edwards/Still Pictures) © Oxford University Press 2009 Agriculture C Cattle ranching Location Central America: at least 2/3 of the arable land is used for cattle production Amazon Basin: about 1/5 had been cleared for farming and cattle ranching * Brazil: - the world’s largest exporter of beef since 2004 - cattle ranching accounted for 60% of forest loss from 2000 to 2005 © Oxford University Press 2009 Agriculture C Cattle ranching Deforestation spreads fast Demand for beef increases Overgrazing occurs Soil is exposed to erosion © Oxford University Press 2009 Cattle ranchers move on new sites and cut trees for creating pastureland Soil quality deteriorates Agriculture C Cattle ranching – the case of Brazil Cheap and extensive Why is the land supply Amazon rainforest so forofcattle Poorpopular awareness environmental conservation ranching? Attractive price of Brazilian beef Supported by local governments Brazilian beef being free of livestock diseases Expansion of road network, i.e. Trans-Amazonian Highway © Oxford University Press 2009 In Brazil, cattle ranching accounted for 60% of forest loss from 2000 to 2005 Commercial logging Most trees in the tropical rainforests are hardwoods. They are quality raw materials for construction purposes and for making furniture, e.g. Teak, Mahogany, Brazilian Rosewood. © Oxford University Press 2009 Commercial logging Location Central & Western Africa Thailand Indonesia The Amazon Basin, etc. * They export large amount of tropical timbers, sawn wood and plywood to the developed countries. •The US & UK have been the main importers of Mahogany. •The vulnerable Brazilian Rosewood has been harvested as a highly prized wood for decorative veneers, highquality furniture (e.g. musical instruments), resin & oil. © Oxford University Press 2009 Commercial logging Logging in the rainforest is destructive since ... Logging activities are often unchecked / greenwashed. Clear-cutting is carried out. Tools: elephants vs bulldozers, caterpillar wheels, crane? Trees are cut to provide space and to build roads. The roads built by the logging companies provide access for other forest users. © Oxford University Press 2009 Commercial logging Rate of logging accelerates in tropical rainforests because of: © Oxford University Press 2009 Mining and oil and gas exploitation Many rainforests are rich in mineral reserves, e.g. bauxite, coal, tin, and oil and gas deposits, by open-cast, strip and shaft mining methods. Urucu oil and natural gas plant in the Amazon (Credit: Reuters/OTHK) © Oxford University Press 2009 Gold mining in the Amazon (Credit: Reuters/OTHK) Dam construction Hydroelectric power (HEP) is generated in rainforested countries to provide energy with plentiful water supply. HEP is considered the most reliable source of energy in the rainforested countries because: it rains every day in the tropical rainforests; high annual rainfall; water never freezes. The Itaipu Dam in the Amazon rainforest (Credit: Reuters/OTHK) How about the © Oxfordproblems? University Press 2009