d Explain how the following factors influence the distribution of natural

D explain how the following factors influence the

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(d) Explain how the following factors influence the distribution of natural forest. (i) Climate. (4marks) - Rainfall forests grow in areas with high rainfall e.g. over 1200mm. Low rainfall discourages forest growth. - Temperature high temperature over 24 C and humid within the tropical region accelerate plant growth. - Low temperature discourage plant growth. (ii) Altitude. (2marks) - Altitude influences rainfall and temperature. - Very high altitude over 3500m are unsuitable for plant growth since they are too cold. - The lower level of Tropical Mountain are suitable for forestry growth. (iii) Soil. (2marks) Deep fertile soil encourages growth of forests shallow and less fertile soil discourage growth of vegetation. (e) (i) Give three characteristics of softwood in Kenya. (3marks) - Cover 3% of the total land mass. - Located in Kenya highlands. - Consists both indigenous and exotic species. - They are both natural and planted. - Grow on deep fertile soil. - Take short time to mature. - Consists only one plant species. - Harvesting done on small scale. (ii) Four characteristics of softwood in Canada. (4marks) - Cover 60 70% of total land mass. - Mainly natural forest.
Geography 312/1,312/2 Top grade predictor publishers Page | 134 - Forest grow in shallow, thin soil due to glacial erosion. - Species are indigenous. - Trees take longtime to mature. (d) Explain three positive significances of forests products in Kenya. (6marks) - Create job opportunities raising the living standards. - Provision of fuel e.g. firewood and charcoal. - Habitat for world animals. - Control soil erosion. - Provide poles for fencing and supply of electricity. - Make the environment beautiful. - Source of raw materials in paper and pulp industry. - Source of timber for construction and making furniture. 10. (a) (i) Define the term pollution. (2marks) Pollution is the emission of solid, liquid and gaseous wastes to environment which contaminates water, soil and air. (ii) State four causes of land pollution. (4marks) - Dumping of garbage particularly in urban centres/inadequate dustbins to put wastes. - Inadequate waste dumping. - Poor sanitation and disposal of human waste. - Poor excessive use of farm chemicals. - Burning of forests. - Mining/quarrying of land dereliction. (b) (i) Name two areas in Kenya which occasionally experience flooding . (2marks) - Budalangi. - Nyando - Kano Plains. - Lower Tana/Tana River County. (ii) Explain three major causes of widespread flooding in Kenya . (6marks) - Blockage of drainage in urban centres. - Siltation of rivers and lakes making them shallow. - High rainfall in adjacent highlands leading to flooding in lowland. - Landslide blocking a river leading to flooding. (iii) State four methods used in controlling and managing floods in Kenya. - Construction of dams/check dams to reduce water velocity and water volume downstream. - Construction of dykes along rivers.

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