Class 8 Science
Importance of Forest:
- Forest provides home to a large variety of animals.
- Trees take up carbon dioxide and release oxygen during photosynthesis. Thus, trees help in maintaining a balance between oxygen and carbon dioxide in the atmosphere.
- Forest is an important source of many raw materials for various purposes.
- Forest provides firewood, kendu leaves, lac, timber, etc.; especially to tribal people.
- Forest helps in precipitation.
- Forest helps in preventing soil erosion which may happen due to flood and wind.
- Forest helps in improving soil fertility.
- Forest helps in natural recharge of groundwater.
Deforestation: Clearing of forest for making way for human activities is called deforestation.
Causes of Deforestation:
- Procuring land for cultivation
- Building houses and factories
- Making furniture and using wood for fuel
- Clearing land for making roads, railway lines, dams, etc.
- Grazing cattle
Effects of Deforestation
- Reduced forest cover increases the level of carbon dioxide in the atmosphere. This results in global warming.
- Reduces groundwater level.
- Reduces rainfall.
- Reduces soil fertility.
- Can result in droughts or in excess flood.
- May also lead to desertification.
Desertification: Conversion of fertile land into desert is called desertification. It happens in following steps:
- Pace of soil erosion increases when forest cover is reduced.
- Hard and rocky layer is exposed once topsoil is removed.
- Soil becomes deficient in humus and thus becomes infertile.
- The land turns into desert in due course of time.
Conservation of Forest and Wildlife
Biosphere: The part of the earth where all living organisms are present is called biosphere. Biosphere is the narrow zone between hydrosphere, troposphere and atmosphere.
Biodiversity: Variety of organisms in a given area is called biodiversity in that area.
Flora: All the plant species in a given area are collectively called flora of that area.
Fauna: All the animals species in a given area are collectively called fauna of that area.
Protected Areas: Some areas have been demarcated to protect flora and fauna and their habitat. Such areas are called protected areas. Various rules, methods and policies to protect and conserve forests and wildlife are formulated by the government. There are of following types of protected areas:
- Sanctuary: A sanctuary is an area where animals are protected from any disturbance to them or their habitat. In a wildlife sanctuary; poaching (killing) or capturing an animal is strictly prohibited.
- National Park: A national park is an area which is reserved for wildlife, and where wildlife can freely use the habitat and natural resources. Satpura National Park is the first reserve forest of India.
- Biosphere Reserve: A biosphere reserve is a large area of protected land for conservation of wildlife, plant and animal resources and traditional life of the tribals living in that area.
A biosphere reserve encompasses many other protected areas; like wildlife sanctuary and national park. For example; Pachmarhi Biosphere Reserve contains one national park and two wildlife sanctuaries. They are as follows:
- Satpura National Park
- Bori Wildlife Sanctuary
- Pachmarhi Wildlife Sanctuary
Endemic Species: A species found exclusively in a particular area is called endemic species. Sal, wild mango, bison, Indian giant squirrel and flying squirrel are endemic to Pachmarhi Biosphere Reserve. Endemic species are at greater risk of extinction because they are not found anywhere else.
Species: A group of population capable of interbreeding is called species. Capability of interbreeding is the most important criteria for species.
Project Tiger: Project Tiger was launched in 1973 to protect and conserve tigers in India. This project is aimed at protecting the Bengal Tigers. Project Tiger has been successful in improving the population of tigers in India. As present, there are more than 2,000 tigers in India.
Endangered Species: Species which are under threat of extinction are called endangered species. Examples: Elephants, lions, wild buffalo, etc.
Extinct Species: Species which no longer exist on earth are called extinct species, e.g. dinosaurs, dodo, etc.
Ecosystem: A system of interdependencies among all living beings and non-living things in a given area is called ecosystem.
Red Data Book: The International Union for Conservation of Nature (IUCN) first came with the Red Data Book. It is a source book which keeps record of all the endangered plants and animals. Each country publishes its own version of Red Data Book from time to time.
Migration: Long distance travel by animals to escape harsh conditions is called migration. Many birds and many other animals migrate long distances during unfavourable season. Human beings also migrate in search of livelihood. Siberian Crane migrates from Siberia to India during winters to escape harsh conditions in Siberia and to get comfortable conditions and food in India.
Recycling of Paper: Paper can be recycled many times. As paper is made from wood pulp so recycling of paper helps in saving trees.
Reforestation: Planting trees to recover forests is called reforestation. Reforestation can take place naturally as well as by human intervention.
Indian Forest (Conservation) Act: The Indian Forest (Conservation) Act came into effect in 1927. This Act is aimed at preservation and conservation of natural forests, and at meeting the basic needs of the people who live in or near the forests.