Notes On Importance of Forest - CBSE Class 7 Science
 Forest A forest is an area on land forming an ecosystem. It is a precious resource given by nature. It is a constantly changing environment made up of a variety of living organisms. Forests influence the environment of the area. Forests vary with the climatic conditions prevailing in the area they are present. Forests include living organisms like wild animals, trees, shrubs, ferns, mosses, lichens, fungi and microscopic soil organisms. Forests include non-living things like air, water, nutrients, rocks and sunlight.  Significance of forests Forests serve different purposes. Forests are a very important natural resource provided to us. It is very important for every country to have 30% land covered by forests.  Preservation of water cycle: Forests maintain water cycle on earth. Plants in forests absorb water from the soil through their roots. Transpiration is the process by which plants release excess water into the atmosphere in the form of water vapour. Condensation is the process by which water vapour along with water vapour from the oceans rises in the atmosphere and condenses to form clouds. Precipitation involves moving of clouds on to the land due to sea breeze and result in rainfall. Rainwater seeps into the ground and increases the level of water table. Maintenance of temperature and oxygen levels: Transpiration involves the release of water vapour into the environment thereby cooling the hot air. This helps in regulating the temperature in atmosphere. During photosynthesis, plants take in carbon dioxide to prepare food thereby decreasing its excess amount in the atmosphere. During photosynthesis , plants release out oxygen as a by-product. Oxygen is essential to animals and human beings. Plants make our air fresh with oxygen. Hence, forests are termed to be 'Green Lungs'. More the number of trees, more is the oxygen released. Prevention of global warming: Carbon dioxide is considered to be a greenhouse gas. Its increased level in the atmosphere results in greenhouse effect thereby causing global warming. Trees in the forests absorb carbon dioxide from the environment during photosynthesis and regulate its levels in the atmosphere. Global warming is prevented by forests. Prevention of dust storms and soil erosion: Trees in the forest hold the soil firmly with their roots which bind with the soil particles and prevent it from erosion. Trees also regulate strong winds and reduce dust storms. Rich source of wood: Forests provide us with rich quality of wood. Wood is used in constructions, furniture and some of it is also used as fuel. Charcoal is also used as a fuel which is made from firewood. Forests and their products:  Different products provided by forests are elucidated. Trees provide us with variety of vegetables and fruits. Trees provide us medicinal products used in curing many diseases and healing purposes. Trees provide raw material for paper industry, matchstick industry, coir industry etc. Trees provide us with latex, gums and resins. Trees inhabit lac insects which in turn provide us lac. Trees support bee-hives which in turn provide us honey and bee wax. Forests provide us with spices and oils. Forests are abode of wildlife. We obtain bones, hides and fur from animals. Animal bones are used in making animal charcoal. Charcoal is used as a source of energy in sugar industries and oil refineries. Forests as breeding grounds: Since forests are natural habitat for a variety of wild plants and wild animals, there is a lot of chance for inter breeding of organisms. Due to safe and favourable environment for breeding, there is a chance for evolution of new life. Forests and tribals: Forests provide shelter for many people along with animals and plants. The people living in forests are termed to be tribals. Tribals depend on forests for their livelihood. Forests act as a protective camouflage for the organisms living in them. Forests and food chains: Forests inhabit many animals and plants. Living organisms based on their nutrition are classified into different types namely producers, consumers and decomposers. Producers synthesise their own food. Consumers depend on produces or other consumers for their food. Decomposers depend on dead and decaying matter for their food.  These categories occupy different levels in the food chain. Forests help in energy transfer and maintain food chains. Deforestation Destruction of trees in the forest area and converting large area of land as a habitat for human beings is called as deforestation. Deforestation has many ill-effects on the environment. Loss of forest products provide by plants and animals living in the forests Loss of different species of animals and plants. Food chains are disturbed due to their loss. Soil is eroded easily by wind and water. Increase of carbon dioxide levels in the atmosphere due to the absence of trees for absorbing this gas. Increased CO2 levels lead to global warming which inturn cause melting of polar icecaps. Rainfall becomes scanty as there are no trees. Tribals living in the forests lose their habitat. Afforestation Afforestation is planting of trees in barren lands to increase the area under forests. Afforestation influences the climate of a particular area and shows positive effect on the environment. Afforestation helps in restoring balance in the environment. Government has to insist on everybody planting trees in their lifetime. Government has to take necessary actions in converting waste lands into forests.

#### Summary

 Forest A forest is an area on land forming an ecosystem. It is a precious resource given by nature. It is a constantly changing environment made up of a variety of living organisms. Forests influence the environment of the area. Forests vary with the climatic conditions prevailing in the area they are present. Forests include living organisms like wild animals, trees, shrubs, ferns, mosses, lichens, fungi and microscopic soil organisms. Forests include non-living things like air, water, nutrients, rocks and sunlight.  Significance of forests Forests serve different purposes. Forests are a very important natural resource provided to us. It is very important for every country to have 30% land covered by forests.  Preservation of water cycle: Forests maintain water cycle on earth. Plants in forests absorb water from the soil through their roots. Transpiration is the process by which plants release excess water into the atmosphere in the form of water vapour. Condensation is the process by which water vapour along with water vapour from the oceans rises in the atmosphere and condenses to form clouds. Precipitation involves moving of clouds on to the land due to sea breeze and result in rainfall. Rainwater seeps into the ground and increases the level of water table. Maintenance of temperature and oxygen levels: Transpiration involves the release of water vapour into the environment thereby cooling the hot air. This helps in regulating the temperature in atmosphere. During photosynthesis, plants take in carbon dioxide to prepare food thereby decreasing its excess amount in the atmosphere. During photosynthesis , plants release out oxygen as a by-product. Oxygen is essential to animals and human beings. Plants make our air fresh with oxygen. Hence, forests are termed to be 'Green Lungs'. More the number of trees, more is the oxygen released. Prevention of global warming: Carbon dioxide is considered to be a greenhouse gas. Its increased level in the atmosphere results in greenhouse effect thereby causing global warming. Trees in the forests absorb carbon dioxide from the environment during photosynthesis and regulate its levels in the atmosphere. Global warming is prevented by forests. Prevention of dust storms and soil erosion: Trees in the forest hold the soil firmly with their roots which bind with the soil particles and prevent it from erosion. Trees also regulate strong winds and reduce dust storms. Rich source of wood: Forests provide us with rich quality of wood. Wood is used in constructions, furniture and some of it is also used as fuel. Charcoal is also used as a fuel which is made from firewood. Forests and their products:  Different products provided by forests are elucidated. Trees provide us with variety of vegetables and fruits. Trees provide us medicinal products used in curing many diseases and healing purposes. Trees provide raw material for paper industry, matchstick industry, coir industry etc. Trees provide us with latex, gums and resins. Trees inhabit lac insects which in turn provide us lac. Trees support bee-hives which in turn provide us honey and bee wax. Forests provide us with spices and oils. Forests are abode of wildlife. We obtain bones, hides and fur from animals. Animal bones are used in making animal charcoal. Charcoal is used as a source of energy in sugar industries and oil refineries. Forests as breeding grounds: Since forests are natural habitat for a variety of wild plants and wild animals, there is a lot of chance for inter breeding of organisms. Due to safe and favourable environment for breeding, there is a chance for evolution of new life. Forests and tribals: Forests provide shelter for many people along with animals and plants. The people living in forests are termed to be tribals. Tribals depend on forests for their livelihood. Forests act as a protective camouflage for the organisms living in them. Forests and food chains: Forests inhabit many animals and plants. Living organisms based on their nutrition are classified into different types namely producers, consumers and decomposers. Producers synthesise their own food. Consumers depend on produces or other consumers for their food. Decomposers depend on dead and decaying matter for their food.  These categories occupy different levels in the food chain. Forests help in energy transfer and maintain food chains. Deforestation Destruction of trees in the forest area and converting large area of land as a habitat for human beings is called as deforestation. Deforestation has many ill-effects on the environment. Loss of forest products provide by plants and animals living in the forests Loss of different species of animals and plants. Food chains are disturbed due to their loss. Soil is eroded easily by wind and water. Increase of carbon dioxide levels in the atmosphere due to the absence of trees for absorbing this gas. Increased CO2 levels lead to global warming which inturn cause melting of polar icecaps. Rainfall becomes scanty as there are no trees. Tribals living in the forests lose their habitat. Afforestation Afforestation is planting of trees in barren lands to increase the area under forests. Afforestation influences the climate of a particular area and shows positive effect on the environment. Afforestation helps in restoring balance in the environment. Government has to insist on everybody planting trees in their lifetime. Government has to take necessary actions in converting waste lands into forests.

#### Activities

 Activity 1 Si.edu has created an interesting and interactive animation to cover almost all the topics related to 'Forest'. This video  includes the changes in the forests according to change in the seasons. Seasons are represented as small labels at the bottom. According to the label selected, changes are observed in the forest with proper explanation. Variations in temperature are also considered to record the changes in the forest.  Go to Activity Activity 2 Cirad.fr has created an interactive lesson which brings in enormous amount of information about forests, ill effects of deforestation etc. It also discusses about stake holders of the dorest who are affected by the forest depletion. It kindles socio-economic aspects of forests and their growth.   Go to Activity

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