4.18B: Understand the Effects of Deforestation, Including Leaching, Soil Erosion, Disturbance of Evapotranspiration and the Carbon Cycle, and the Balance of Atmospheric Gases

DEFORESTATION: Permanent destruction of a forest via the removal or clearance of trees

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• Deforestation is human-induced, and is primarily driven by the need for timber and cleared land for agricultural purposes

EFFECTS OF DEFORESTATION:

DEFORESTATION

Picture showing the Scale of Deforestation in Madagascar

EFFECTS: LEACHING While trees usually absorb Minerals and Nutrients from the soil through their roots, the loss of trees will lead to unused Nutrients and Minerals remaining in the soil As a result, this unused Nutrients and Minerals may be washed away Into rivers and lakes by rain - leaching, hence causing eutrophication SOIL EROSION While tree Roots help in stabilising the soil to prevent erosion by rain, the loss of trees will cause the soil to be loose and unstable As a result, the soil may be washed away by rain, inhibiting vegetative growth DISTURBANCE IN WATER CYCLE As transpiration in trees release Water vapours into the atmosphere to condense into clouds and returned to land via precipitation - e.g, rain, the loss of trees will result in less transpiration As a result, this will have a knock-on effect on the Water cycle, causing droughts due to the lack of precipitation UNBALANCED ATMOSPHERIC OXYGEN AND CARBON DIOXIDE (CARBON CYCLE) As trees conduct Photosynthesis to absorb Carbon Dioxide and release Oxygen, the removal of trees will result in less Photosynthesis As a result, less Carbon Dioxide will be removed from the atmosphere, causing atmospheric Carbon Dioxide levels to increase In parallel, less Oxygen will be produced and released into the atmosphere, causing atmospheric Oxygen levels to decrease over a long period of time Additionally, deforestation via the combustion of trees produce Carbon Dioxide, further increasing Carbon Dioxide levels in the atmosphere - disruption to the carbon cycle