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The Disappearing Canopy

The Disappearing Canopy. The Causes. Agriculture. What human activities cause tropical deforestation?. Commercial logging. Dam construction. Mining. What human activities cause deforestatio n in tropical rainforests?. Agriculture. Commercial logging. Mining. Dam construction.

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The Disappearing Canopy

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  1. The Disappearing Canopy The Causes

  2. Agriculture What human activities cause tropical deforestation?

  3. Commercial logging Dam construction Mining

  4. What human activities cause deforestation in tropical rainforests? Agriculture Commercial logging Mining Dam construction

  5. Population growth What are the underlying causes of tropical deforestation? Tropical rainforests provide land and resources for people. People demand for more food, timber, minerals, etc. Population increases Population Resources demanded ( decrease / increase ) Resources demanded

  6. What are the underlying causes of tropical deforestation? Why is population growth high in rainforested countries? This is no official family planning in Brazil because of the influence of the Roman Catholic Church. Among Malays, Chinese and Indians lived in Malaysia, Malays tend to have more children in the family. Their ideal family size is to have more than four children. As long as child mortality remains high, people will continue to have large families.

  7. Poverty People picking up waste in a landfill in Cambodia (Credit: Ng Kim Hung) What are the underlying causes of tropical deforestation? Many tropical countries have a low level of economic development. The people are poor and receive little education. Governments of poor countries do not have enough capital for economic development. Levels of technology and productivity is low. These countries are usually heavily in debt.

  8. Government policy What are the underlying causes of tropical deforestation? Provide subsidies to commercial farmers Encourage migration of people to the rainforests Loose land tenure laws enabling developers to buy land in the rainforest Improve road network to increase accessibility Local governments are attracted by loans given by international loan agencies for financing projects in exploiting rainforests Corruption

  9. Agriculture A Shifting cultivation Shifting cultivation is mostly practised by native peoples and landless or poor peasants. Shifting cultivatorsgrow different crops, such as maize, beans, yams, bananas and pineapples. Some grow tree crops such as cocoa and coffee.

  10. (Credit: Mark Edwards/Still Pictures) Agriculture The cultivators clear the site by cutting and burning the trees A Shifting cultivation The cultivators abandon the existing plot and move to a new plot of land (Credit: Yann Arthus-Bertrand/Corbis) The cleared plot is cultivated for several years until the soil nutrients are used up

  11. Agriculture A Shifting cultivation The carrying capacity of the land in tropical rainforest is low. Therefore, shifting cultivation is considered a sustainable practice. Major characteristics of shifting cultivation: Subsistence, mainly for own consumption small farm size labour intensive staple crop growing Footage showing shifting cultivation in western Africa Please click to browse online

  12. 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 tropical rainforest? More landless peasants becoming shifting cultivators in the rainforest also cause more destruction to the rainforest Soil fertility declines The cultivation cycle is shortened

  13. 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)

  14. 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 …

  15. 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.)

  16. Agriculture B Plantations Location Rubber / oil palm plantation: West Malaysia Coffee plantation: Brazil Cocoa plantation: West Africa & Caribbean areas Banana plantation: Caribbean areas

  17. Agriculture B Plantations Major characteristics of plantations: carried out by large corporations monoculture (single crop cultivation) (Credit: Fernando Bueno/Getty Images) Commercial, export- oriented large farm size cash crop growing Soybean plantation in Brazil

  18. Agriculture B Plantations Economic development results in a large demand for tropical cash crops. This accelerates the destruction of the tropical rainforest. (Credit: Fernando Bueno/Getty Images) In recent years, more soybeans have been grown in the rainforest to satisfy the increasing demand for biofuel. Soybean plantation in Brazil

  19. 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

  20. Agriculture C Cattle ranching Tropical rainforests are cleared to provide pastureland for cattle ranching. Major characteristics of cattle ranching in tropical rainforests: commercialextensive large farm size mainly for export Cattle ranching in Brazil (Credit: Mark Edwards/Still Pictures)

  21. 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

  22. Agriculture C Cattle ranching Deforestation spreads fast Demand for beef increases Cattle ranchers move on new sites and cut trees for creating pastureland Overgrazing occurs Soil is exposed to erosion Soil quality deteriorates

  23. Agriculture C Cattle ranching – the case of Brazil Why is the Amazon rainforest so popular for cattle ranching? Cheap and extensive land supply Attractive price of Brazilian beef Poor awareness of environmental conservation Supported by local governments Brazilian beef being free of livestock diseases In Brazil, cattle ranching accounted for 60% of forest loss from 2000to 2005 Expansion of road network, i.e. Trans-Amazonian Highway

  24. 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.

  25. 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, high-quality furniture (e.g. musical instruments), resin & oil.

  26. 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. Commercial logging Logging in the rainforest is destructive since ...

  27. Commercial logging Rate of logging accelerates in tropical rainforests because of: Improved logging and transport technologies Increased environmental awareness of the moredeveloped countries Illegal logging activities Poor forest management

  28. 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 Gold mining in the Amazon (Credit: Reuters/OTHK) (Credit: Reuters/OTHK)

  29. 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. How about the problems? The Itaipu Dam in the Amazon rainforest (Credit: Reuters/OTHK)

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