Forests - Our Lifeline

IMPORTANT TERMS

Autotrophs                   Organisms which can make their food by the process of photosynthesis.

Heterotrophs                Organisms which depend directly or indirectly on plants for their food. E.g. Rabbit, Lion.

Saprotrophs                 Organisms which feed on dead and decaying organic materials. e.g. Bacteria

Decomposers               Microorganisms which convert dead plants and animals tissues to humus.

Herbivores                   Animals which eat only vegetation such as plants, grass. E.g. Rabbit, cow.

Carnivores                   Animals which eat other animals to survive. E.g. Lion.

Omnivores                   Animals that eat both plants and other animals. E.g. bear.

Scavengers                  Animals which eat the flesh of dead animals. E.g. Vulture.

Food Chain                  A process in which one organism consumes other organism to transfer food energy.

Food Web                    Several food chains are interconnected and form a web called food web.

Humus                         An organic substance formed by the decomposition of decaying plant material.

 

FOOD CHAIN

All animals depend directly or indirectly on plants for their food. Food chain is a chain of organisms in which each organism is eaten by the next member in the chain. The food chain begins with green plants. An example of food chain is given below:

 

Grass ---> Grasshopper ------> Frog ------> Snake ---------> Eagle

 

In this food chain, grass is eaten by grasshoppers. Grasshoppers are eaten by frogs and frogs are eaten by snakes. The snakes are eaten by eagles. When the grasshopper eats the grass, and the other animals eat one another, the chemical energy is passed along the food chain.

 

Several food chains are interconnected in an ecosystem. The interconnected food chains are known as food web. If any of the components is removed from the food chain, all other components would be affected.

 

Plants are known as producers because they prepare their own food through photosynthesis using sunlight and all species depend on them. Primary consumers are those animals which depend on plants for their food. E.g. herbivorous animals such deer, rabbit, cow are considered as primary consumers. Secondary consumers are those which feed on herbivorous animals. E.g. Carnivorous animals such as lion, tiger are known as secondary consumers.

 

Green plants trap solar energy through the process of photosynthesis. This energy is stored in the plants as chemical energy. When plants are consumed by the herbivores, the chemical energy gets transferred to the animals. When herbivores are eaten by the carnivores, the energy gets transferred to them. This process of energy transfer goes on in nature as a part of the food chain.

LAYERS OF A FOREST

A forest is divided into following layers according to the height of the plants and trees:

Canopy is the uppermost layer of branches and leaves formed by closely spaced tall rainforest trees. Most of the plants and animals in the forest are found in the leafy world known as canopy. The canopy may be 100 feet above the ground. It is made up of the overlapping branches and leaves of trees.

Crown is that part of the tree, which features branches that grow out from the trunk and support the leaves.

Understory is a dark, cool area below the canopy, but above the ground. The understory is shaded from much of the sunlight by the canopy.

Forest floor is the bottom layer of the rainforest. It is the area where fallen, decomposing leaves, fruits and seeds lay on the ground.

USES OF FORESTS

About one-third of the world's land surface is covered with forests.

Forests acts as a natural absorber of rainwater and allow it to seep through. If there are no trees, rain water would hit the ground directly and cause flooding. Thus, trees help in preventing the floods.

Forests are called green lungs of the Earth as they release oxygen and consume carbon dioxide during the process of photosynthesis. They provide oxygen to animals and human beings for respiration and maintain a balance of oxygen and carbon dioxide in the atmosphere.

Trees play an important role in the water cycle and help in increasing rainfall. If a large number of trees are destroyed, it disturbs the water cycle and lead to reduced rainfall.

Trees help in regulating the climate of a place. They absorb water from the soil and release some of it as water vapour. Thus, they help in keeping the surrounding air cool. Trees give us timber which is used for making furniture E.g. Sal, mahogany, teak etc. Plants are also used to make medicines. E.g. The bark of the cinchona trees contains quinine, which is used for treating malaria. We get several other products such as gums, oils, spices, paper, fuel wood and matchsticks.

IF FORESTS DISAPPEAR

Deforestation is the main factor responsible for loss of biodiversity. Deforestations causes destruction of the natural habitats of plants and animals, and this in turn leads to the loss of biodiversity.

Plants and trees absorb carbon dioxide from the atmosphere. If plants are destroyed, then the level of carbon dioxide in the atmosphere will rise. The high levels of carbon dioxide will trap more heat radiations, leading to global warming.

The roots of the trees help in binding the soil particles together. When the trees are destroyed, soil is left loose and is easily eroded or washed away.

CONSERVATION OF FORESTS

Illegal logging is also one of the major causes of deforestation. Strict measures should be taken by the government to prevent illegal logging and to conserve the forests.

Overgrazing by cattle is a human related cause that contributes to deforestation. It can be prevented by providing sufficient pastures, especially in areas adjoining forests.

Every year, a large number of trees get burned because of forest fires. It also has a devastating effect on animals living in forest and people living nearby. Forest fires should be prevented to conserve the forests.

Afforestation can also help in conserving the forests. It is an act of planting of trees to create a forest on non-forest land. The main purposes for implementing afforestation are commercial forestry and preservation of environment.

 

INTERESTING FACTS

 

• More than 80% of the Earth’s natural forests have already been destroyed.
• 16 types of forests are found in India including the evergreen tropical rain forests, dry alpine scrub forests, semi evergreen rain forests, deciduous monsoon forests, thorn forests, subtropical pine forests and more.  
• Three- quarters of the population of the entire world depend on wood as this is the main source of energy for them.
• Human beings are at the end of the food chain.
• Lightning, burning campfires or cigarettes, hot winds, and even the sun can all provide enough heat to spark a wildfire.
• The largest tree in the world by volume is a giant sequoia called General Sherman which has a trunk 10m round and contains an estimated 1486 cubic metres of wood.
• Assuming it lives at least 50 years, a tree exhales 6,000 pounds of oxygen in its life, or about 120 pounds per year.