Forests - Natural Resources - PDF

Okay, here is the transcription of the provided text, formatted in Markdown. ### Chapter - Seventeen ## Forests **UNIT - 7** **Natural Resources** **Let us learn about** * Layers of forest * Interdependence of Plants and animals * Conservation of Forests * Uses of forests * Destructi...

Okay, here is the transcription of the provided text, formatted in Markdown. ### Chapter - Seventeen ## Forests **UNIT - 7** **Natural Resources** **Let us learn about** * Layers of forest * Interdependence of Plants and animals * Conservation of Forests * Uses of forests * Destruction of Forests A forest (derived from Latin word 'foris' means "out of doors") is a large area covered with different kinds of trees, shrubs, herbs and where many kinds of animals live. About *one-third* of the world's land surface is covered with forests. Approximately *30 percent* of the world's total land area is covered with forests. In India, the forest cover is about *21 percent* of the total geographical area. Forest provide 'home' to many animals and plants and many valuable products for human beings. All the plants and animals in any forest depend on each other. Many tribal people living in forest also depend on plants, trees and animals living there. In this chapter, you will learn about the importance of forest, its layers, living community, the food chains existing in the forest and the interdependence of plants and animals living in the forests. ### LAYERS OF FOREST A forest contains different layers of plants. These layers can be divided on the basis of their heights as **canopy**, **crown**, **understorey** and **forest floor**. **Canopy**: The branches of the tall trees form a shady and protective umbrella over the rest of the plants in the forest. This is called a **canopy**. Many animals like snakes, toucans and tree frogs live in this layer, since food is in abundance. **Crown**: The part of a tree, above the stem, which has branches is known as the **crown** of the tree. Crowns differ in shape and size in different trees. *The image shows a cross-section of a forest, labeling the canopy, understorey, and forest floor.* **Understorey**: The layer of vegetation just below the canopy is the understorey. It usually consists of palms, small trees and shrubs. These trees and shrubs are well adapted to live in less sunlight. The plants of this layer grow larger leaves to capture maximum sunlight. This layer is hot and damp. This layer is a home to a number of animals such as birds, lizards, snakes, owls, red-eyed tree frogs, etc. Larger predators like leopards, pythons, jaguars, etc. also live in this layer. **Forest Floor:** The forest floor is dark, humid and warm. A very few plants can grow in this layer due to the conditions prevailing in this region. Usually, leafless plants like mosses, ferns and lichens are found growing on the forest floor. The forest floor is covered by dead and decaying leaves, fruits, twigs, dead plants and animals, etc. Decomposers like bacteria, fungi, etc. are also found here. They decompose the dead plants and animals into dark coloured organic matter called **humus**. Forest floor is also the home to a variety of centipedes, millipedes, beetles, ants and cobras. Larger animals like elephants, lions, rhinoceros, etc. also live on the forest floor. *The image shows a forest floor with fallen leaves and tree trunks.* **Activity 17.1** **To show that decaying matter is warm.** Dig a small pit and put fallen leaves and vegetable waste in it. Cover the pit with soil and sprinkle some water. Observe the upper layer of the soil after 3-4 days. You will find that the soil in the pit feels warm inside. India is a very vast country. Due to its large geographical area and its varied topography and climatic conditions, It has a diverse range of forests. The most common of these are tropical rainforests, temperate deciduous forests, Himalayan pine forests, mangrove forests, monsoon forests, etc. **Activity 17.2** To show the various types of forests on the map of India. Take a political map of India and show on it the various types of forests. Which type of forests are found in the region you live? Which trees are commonly found in these forests? Why do you think some other types of forests are not found in these forests? ### **USES OF FORESTS** Forests are an important natural renewable resource having the ability to regenerate themselves. Without these and the material obtained from them, life would not have been possible. There are some uses of forest which are given below: **Provide food and shelter**: All animals obtain food from the plants, either directly or indirectly. Herbivores feed directly on plants and plant produces while carnivores feed on the flesh of other animals. We obtain fruits and a number of other food products from forests. Forests serve as habitat for a large number of animals. Insects like grasshopper, moth, butterfly, caterpillar, etc. find shelter among plants. Animals like monkeys, squirrels, apes, etc. live on trees. Birds also make their nests on trees. Many tribal people live in forests. They fulfill most of their requirements from forests only. *The image is of a monkey in a tree* **Provide wood**: Trees like *sal, sheesham, teak,* etc. growing in forests provide us wood. The wood obtained from these trees is used for a number of purposes. Superior wood is used for making furniture, sports goods, etc. Low grade wood is used as **fuel wood** for cooking food and heating rooms during winters. **Wood pulp** is also used in the preparation of paper. **Provide a number of other available products**: Besides food and wood, we obtain a number of other valuable things from forests. A number of plants yield medicines. Quinine, a medicine used in the treatment of malaria, is obtained from the bark of cinchona tree. Plants like neem, tulsi, amla, eucalyptus, etc. are well known for their medicinal values. Latex obtained from rubber trees is used for making rubber. Resins obtained from trees is used to make paint and varnish. Eucalyptus, pine and sandalwood yield oil. Babool, kikar, etc. provide us gum. A number of industries such as match industry, paper industry, fibre industry, etc. depend on forests for their raw materials. **Maintain balance of gases in nature**: They produce oxygen by the process of photosynthesis. Forests maintain the balance of carbon dioxide and oxygen in the atmosphere. That is why forests are also called **green lungs of nature**. **Control Floods**: Trees allow water to seep into the soil, through their root system. Forest acts as a natural absorber of rainwater and helps to maintain the water table. Further, the flow of water is also reduced by the presence of trees. In this manner, the impact of floods is greatly reduced. If trees are not present, rain hits the ground directly and floods the area around it. **Prevent soil erosion**: Trees prevent soil erosion by holding the soil particles together through their root system. Thus, wind or water is not able to bring about soil erosion. **Increase rainfall**: Trees in forest absorb water from the soil and release it into atmosphere in the form of water vapour by the process of transpiration. This water vapour forms clouds in the upper atmosphere. These clouds fall down to the earth in the form of rain. Thus, forests increase rainfall. The presence of water vapour in the air surrounding forests brings about cooling effect. Have you ever felt this when you pass by a forest? ### Interdependence of Plants and Animals Plants and animals depend on one another. In fact, they are complementary to each other. **Animals depend on Plants:** Animals depend on plants for the following things: Plants can prepare their own food by the process of photosynthesis. On the other hand, animals lack this ability to prepare food. They obtain food from plants either directly or indirectly. During the process of photosynthesis, oxygen is produced as a by-product. This oxygen is used by animals in the process of respiration. Most of the animals cannot live in absence of oxygen. A number of animals like monkeys, apes, lion, elephants, bear and a number of insects like beetles, ants, grasshoppers, etc inhabit the forests. Thus plants also provide shelter and security to the animals. Thus, animals depend on plants for food, oxygen and shelter. **Plants depend on Animals**: Plants also depend on animals for the following things: The transfer of pollen grains from the anther to the stigma of the same or the other flower is known as **pollination**. This process is necessary for the formation of seeds and reproduction in plants. Honeybees, wasps, butterflies, humming birds, bats, etc. helps the flower in pollination. *Image of a bee* Animals produce carbon dioxide during the process of respiration. Plants use this carbon dioxide in the process of photosynthesis to make food. Animals help in dispersal of seeds from one place to another. The seeds and fruits of a number of plants have spines, hooks, etc. on them. These structures get struck in the hairs of animals which carry them to distant places. The excreta of the animals acts as manure and increases the fertility of soil. It provides nutrients necessary for the growth of plants. ### Food Chain and Food Web A food chain is a series of living things which are linked together because each is the food for the others in the chain. Green plants make their own food by utilising solar energy. The solar energy is converted into chemical energy of food by the green plants so they are called producers. Animals cannot make their own food so they eat plants or other animals. They are called consumers. Animals can be herbivores, carnivores, omnivores, depending on the kind of food they eat. A simple food chain When plants and animals die, bacteria and fungus decompose them to obtain their food and help in returning nutrients to the soil. Thus, the food chains are the way of nature through which energy flows from one organism to another. This way, energy never gets wasted but gets transferred from one level to another. A food chain always proceeds in a straight line. There are several food chains working in nature. All foods chains begin with green plants. When many food chains interlink with each other, they form a food web. *The image shows a typical food web diagram with various animals and plants connected by arrows indicating the flow of energy.* ### DESTRUCTION OF FORESTS Destruction of forests or cutting down of trees on a large scale is called **deforestation**. Areas which were once covered with forests are now concrete jungles, as you find more and more tall buildings. The ever increasing human population has been the most important factor responsible for deforestation. *The image is of logs piled on top of each other.* **The harmful effects of deforestation are :** * Large areas are cleared to make housing colonies, hospitals, markets, offices, etc. for the growing population. * Trees are felled for obtaining fuel wood for cooking. * Forests are cleared for growing crops for the increasing population. * Forests supply raw materials to a number of industries. The forests are cut down to meet the demands of these industries. * Large forest areas are cleared to construct dams for the production of hydroelectricity. * Forest fires and attack of insects and pests also cause large scale destruction of forests. * Overgrazing of animals, whose numbers have increased with increasing human population has reduced the plant cover. **Know More** Every year, India loses about 1.5 metric hectares of forest area because of deforestation. ### CONSERVATION OF FORESTS The maintenance and use of forest products in a way that the forests are not destroyed is called forest conservation. We should follow these methods to conserve our forests. Only diseased and damaged trees should be felled for obtaining fuel wood. If it is necessary to fell trees then same number of trees of the same species should be planted in the nearby area. *The image shows people planting trees.* The forests should be renewed or raised by planting trees. This is termed as **afforestation**. Now-a-days, planned afforestation programmes are conducted by government as well as non-governmental organizations. Forest fires are usually caused due to human carelessness or lightning or due to friction between trees. These fires destroy forests in a large area in no time. Better technology should be used to detect and extinguish forest fires. Forest nurseries should be established on a large scale. People should be made aware about the importance of forests in their lives and the ill- effects of deforestation. National parks, wildlife sanctuaries and biosphere resources should be protected. **Know More** Government of India organizes Van Mahotsav every year in July to encourage tree plantation.