Question 1 Which gas in the atmosphere is utilised by the trees and plants in photosynthesis?
Question 2 Which gas in the atmosphere traps the heat rays reflected by the earth?
Question 3 What are the consequences of deforestation?
Question 4 What is global warming?
Question 5 What is desertification.Name human activities which may lead to desertification?
Question 6 Explain how deforestation makes the soil infertile leading to desertification?
Question 7 Name the gas which is responsible for global warming?
Question 8 How does deforestation reduce rainfall on the one hand and lead to floods in the other?
Question 9 How deforestation leads to extinction of many wild animals and plants?
Consequences of deforestation
The deforestation will have the following consequences:
1)It will lead to shortage of wood and other food products:The wood obtained from forest trees is used as fuel,for making doors,windows and furniture,making paper.It will lead to a shortage of wood for all these purpose.Forest give us useful products such as honey,gum,wax,catechu etc.
2)It will cause an increase in temperature of earth’s atmosphere leading to global warming:Trees use carbon dioxide gas from the atmosphere for the process of food making called photosynthesis.When a lot of trees are cut down during deforestation,then lesser number of trees will be left.The lesser number of trees will use up less carbon dioxide due to which the amount of carbon dioxide in atmosphere will increase.
Carbon dioxide gas trap the sun heat rays reflected by the earth.Trapping of heat rays by carbon dioxide increases the temperature of earth’s atmosphere.This will lead to global warming.The gradual increase in the over-all temperature of earth’s atmosphere due to green house effect caused by the increased level of carbon dioxide in the atmosphere is called global warming.The global warming melt polar ice caps rapidly producing a tremendous amount of water leading to a rise in the sea level.The raised sea-water level will flood the low-lying coastal areas causing huge loss of life and property.
3)Deforestation will cause soil erosion making soil infertile and lead to desertification:The roots of trees bind the particles of top soil together.Due to this binding of soil particles,the wind and water are not able to carry away the top soil due to which the top soil does not become loose quickly.
When the forests are cut down during deforestation,there are no roots of trees which can bind the soil particle together and prevent them from being carried away by strong winds or flowing rain water.Since there is no tree cover on the soil to soften the effect of heavy rain,the bare top soil becomes loose quickly by the force of falling rain water and erode rapidly.
The top soil of earth is most fertile.The removal of top layer of soil during soil erosion,exposes the lower,hard and rocky layer os soil.This lower layer of soil has less humus and is less fertile.Plants do not grow well in this less fertile soil.The fertile land gets converted into a desert.
The process by which fertile land becomes desert is called desertification.
4)Deforestation will cause frequent flooding of rivers leading to loss of life and property:The roots of forest trees help in absorbing some of the rain water and make it percolate into the ground.This reduces the amount of rain water which rushes quickly into rivers and flooding does not occur.When the forest trees are cut down,the percolation of rain water into soil is reduced.A lot of rain water from deforested soil rushes into the rivers quickly,causing floods.Deforestation decreases the water holding capacity of soil which leads to floods.
The eroded soil is carried by flowing rain water into rivers.The eroded soil keeps on collecting on the river bed and decreases depth of river gradually.Due to decreased depth,the water carrying capacity of the river is reduced.When heavy rain occur,the river is not able to carry away all the rain water quickly.The excess water overflows from the banks of the river into the adjoining areas causing flood.These flood damage standing crops,houses and even drown people living in nearby areas.
5)Deforestation affects the water cycle leading to decrease in rainfall.The decrease in rainfall lowers the groundwater level and could cause droughts:The forest trees put a lot of groundwater,sucked through their roots,into the atmosphere as water vapour by the process of transpiration.This water vapour helps in bringing rain in that area.When the forest trees are cut,then the lesser number of trees put less water vapour into atmosphere through trough transpiration.Since less water vapour is put into the atmosphere,there is less rainfall in that area.When there is less rainfall in an area,then less water percolates into the ground.Due to this,groundwater level also gets lowered.The shortage of surface water and groundwater due to persistent low rainfall in an area can lead to droughts.
6)Deforestation leads to extinction of many wild animals and plants:Forests are the natural habitats of many animals,birds and plants.When forest trees are cut down,the natural habitat of wild animals and birds gets destroyed.In the absence of forest trees and plants and animals,wild animals and birds do not get enough food and starve to death.