WHAT IS DEFORESTATION Deforestation is the permanent destruction ofindigenous forests and woodlands. The term does not include the removal ofindustrial forests such as plantations of gums orpines.
DEFORESTATION CONTINUES Deforestation has resulted in the reduction ofindigenous forests to four-fifths of their pre-agricultural area. Indigenous forests now cover 21%of the earths land surface.
WHAT ARE FORESTS AND WOODLANDS? In a forest the crowns of individual trees touchto form a single canopy. In a woodland, trees grow far apart, so that thecanopy is open.
HOW DOES DEFORESTATION HAPPEN Deforestation is brought about by the following: * Conversion of forests and woodlands toagricultural land to feed growing numbers ofpeople. * Development of cash crops and cattleranching, both of which earn money for tropicalcountries.
HOW DOES IT HAPPEN CONTINUES Commercial logging (which supplies the worldmarket with woods such as meranti, teak, mahoganyand ebony) destroys trees as well as opening upforests for agriculture; * Felling of trees for firewood and buildingmaterial; the heavy lopping of foliage for fodder;and heavy browsing of saplings by domesticanimals like goats.
WHY To compound the problem, the poor soils of thehumid tropics do not support agriculture for long. Thus people are often forced to move on andclear more forests in order to maintain production
CONSEQUENCES OF D E F O R E S TA T I O N* A LT E R A T I O N O F LO C A L A N D G LO BA L C L I M A T E S T H RO U G H D I S RU P T I O N OF: a) The carbon cycle. Forests act as a major carbon storebecause carbon dioxide (CO2) is taken up from theatmosphere and used to produce the carbohydrates, fats, andproteins that make up the tree. When forests are cleared, and the trees are either burnt orrot, this carbon is released as CO2. This leads to an increase inthe atmospheric CO2 concentration. CO2 is the major contributor to the greenhouse effect. Itis estimated that deforestation contributes one-third of allCO2 releases caused by people.
CONSEQUENCES OF DEFORESTATION CONTINUES b) The water cycle. Trees draw ground water upthrough their roots and release it into the atmosphere(transpiration). In Amazonia over half of all the water circulatingthrough the regions ecosystem remains within theplants. With removal of part of the forest, the regioncannot hold as much water. The effect of this could bea drier climate.
CONSEQUENCES OF DEFORESTATION CONTINUES * Soil erosion With the loss of a protective cover of vegetation more soil islost. * Silting of water courses, lakes and dams This occurs as a result of soilerosion. * Extinction of species which depend on the forest for survival. Forestscontain more than half of all species on our planet - as the habitat of these species isdestroyed, so the number of species declines (see Enviro Facts "Biodiversity"). * Desertification The causes of desertification are complex, but deforestationis one of the contributing factors (see Enviro Facts "Desertification")
LIST OF REFERENCES THE GAIA ATLAS OF PLANET MANAGEMENT. N Myers(ed.). Pan Books, London, 1985. BEHIND THE WOODFUEL CRISIS. G. Leach and L.Mearns. Capetown: Oxford University. South Africa, 1988. THE FUELWOOD TRAP: A STUDY OF THE SADCCREGION. B. Munslow. United States of America: McGraw Hill. 2003. WHOSE TREES? A PEOPLES VIEW OF FORESTRY AID.M. Hisham and J. Sharma. Panos Institute, London, 1991. WWF ATLAS OF THE ENVIRONMENT. G. Lean and D.Hinrichsen. Helcoan Publishing, Oxford,U.K., 1992.