ZIMSEC O Level Geography Notes:Natural Resources:Tropical deforestation
- Deforestation in tropical rain forests is mainly a result of the need to meet local and external needs.
- Local needs are generally basic and include the following:
- Agriculture- population pressures and rural poverty forces people to migrate to forest areas in search of land for settlement and subsistence farming. Forests are cleared using the slash and burn method for the purposes of growing crops.
- These areas are quickly leached by the heavy rains and become unproductive, forcing the farmers to move on because regeneration of vegetation is slow and can take up to 20 years.
- Wood fuel – search of wood fuel has resulted in the clearing of large areas of forest. Alternative energy sources are expensive for the rural communities.
- Building materials and fencing – shelters are mainly constructed from wood, wood fibre and grass. Fences to keep out wild animals are also use the same materials.
- The basic shelter in rural Africa is the pole and dagga hut. It is cheap and easy to construct but meets the basic requirements.
- Cattle pens are also mainly made out of wooden poles. Since these structures are not durable, more and more timber is required for the repair and renewal resulting in further deforestation and land degradation.
- Hunting – large forests areas are destroyed by veld fires caused by hunters to push out wild animals.
Forests are also destroyed for commercial purposes which include the following.
- Commercial logging – to obtain tropical hardwoods for export to developed countries in order to earn foreign currency. Foreign and indigenous companies have been licensed to exploit timber in the rainforests for local use and export purposes.
- Large mining operations – the iron ore mines of the Amazon and copper mines in the Congo, have resulted in the clearing of large areas of forest to exploit the minerals.
- Commercial ranching – to produce beef for export. Rainforest in both Africa and the Amazon basin are being replaced by grass to provide grazing land for the cattle.
- Commercial plantation – to produce raw materials for both the local and overseas markets have replaced much of the original rainforsts in both Africa nad the amazon basins for example the coffee planatation of Ghana, the oil palm planataions of Nugeria and the rubber planataions of Liberia and the DRC.
- Generation of power – to meet demand from the developing industrial twons in the rainforest areas has seen the establishment of large hydroelectric schemes in these areas. Large dams have been constructed by large foreign companies and governemnet.
Tropical foretsts are more difficult to exploit as a result of:
- The absence of pure stands which results in the detruction of a lot of plan species in search of scattered commercial trees.
- Wet and muddy conditions, making transportation difficult.
- The thickness of forests making both felling and transportation difficult and expensive.
- Presence of creepers and buttress roots.
- Hot humid conditions not suitable for the human labour force.
- Tropical pests and diseases.
- Heavy logs which sink in water and therefore making river transoration impossible
These difficulties have resulted in selective cutting which makes reforestation difficult and clearing of large areas to establish roads and railways to coastal ports for export purposes.
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