CBSE Class 7 Science Revision Notes Chapter 17

CBSE Class 7 Science Revision Notes Chapter 17 – Forests: Our Lifeline

A forest is home to a wide variety of living things and is rich in biodiversity. It is a dense area of trees, which is crucial for regulating the climate and environment. Forests help remove pollutants from the air and supply oxygen to support life. They are effective sound absorbers.

This chapter describes the environment and feelings of a young child who is going on their first forest exploration with a new friend. Students will also learn the value of forests and the negative effects of deforestation.

Extramarks Revision Notes provide key information for all of the chapters in Class 7 Science.  Class 7 students can utilise the Extramarks Revision Notes for Class 7 Science Chapter 17 to score more in the examinations. This will help them advance their academic careers.

These notes include important topics like deforestation, the value of forests, the effects of deforestation, the food chain, the food web, etc. which are systematically covered in bullet points for ease of understanding. These notes are clear, simple, and ideal for effective revisions.

Revision Notes for CBSE Class 7 Science Chapter 17

Access Class 7 Science Chapter 17 – Forests: Our Lifeline Notes


  • It is a sizable area of land that is heavily vegetated with trees, bushes, and other plants.
  • Forests are home to a variety of materials.
  • A wide range of plants, animals, and microorganisms can be found in forests.
  • In a forest, the highest layer of vegetation is made up of trees, while the lowest layer is made up of shrubs and herbs.
  • Various layers of vegetation can provide food and cover for animals, birds, and insects.
  • All of the elements in the forest are interconnected.
  • Forests can regenerate and it constantly changes and grows. 
  • The soil, water, air, and living beings interact with one another in the forest.
  • Forests aid in preventing soil erosion.
  • Forest growth and regeneration are aided by soil.
  • Communities that live in forests depend on forests to survive.
  • The climate, the water cycle, and air quality are all impacted by forests.


The act of removing trees from their natural habitat is known as deforestation.

Importance of Forests:

Humanity places a high value on forests. The value of forests is illustrated below:

  • Trees in the forests can be cut for timber.
  • The vast plant and tree reserves found in forests contribute significantly to maintaining the quality of air.
  • Forests serve as habitats for various organisms and provide shelter.
  • The roots of the trees that grow in forests firmly grip the soil particles and stop erosion.
  • Forests prevent floods by maintaining the water cycle on earth.
  • Noise pollution is decreased by the forest’s ability to absorb loud sounds and noise from its surroundings.

Independence of Plants and Animals in the Forest:

Both plants and animals rely on one another to survive.

All organisms interact with one another and their physical surroundings to obtain energy and survive.

Effects of Deforestation:

Effects of deforestation include an increase in carbon dioxide levels, which raise the earth’s temperature. 

The loss of forests results in the loss of natural habitats for animals and birds.

Flooding will occur because the soil would not be able to hold the water.

Deforestation puts the environment and the lives of people in danger.

Conservation of Forests:

Some of the key actions for forest protection include:

  • Prevent animals from overgrazing.
  • Promote tree plantation.
  • Protect the environment.
  • Avoid forest fires.

Food Chain:

The interdependence between producers and consumers is examined using various linkages that resemble a chain or organism interdependence.

Food Web:

It is a network of linked food chains that can be used to symbolise various biological relationships.

FAQs (Frequently Asked Questions)

1. How important are woods to human survival?

Forests provide humankind with many advantages. They exchange carbon dioxide for oxygen. They supply numerous materials such as wood, rubber, lumber, medicinal herbs, etc. They aid in maintaining healthy flora and fauna as well. Soil preservation is one of its crucial roles. They also help to bring rain and control the weather. Hence, they are appropriately referred to as lifelines for human survival.

2. How are nutrients recycled in the forest?

The following is the process by which forests recycle nutrients:


  • Nutrients in the soil are absorbed by plants, insects, and microbes.
  • Birds and animals in the forest consume nutrients from plants or other animals.
  • In the forest, when insects, animals, plants, and birds pass away, microbes break down their corpses. In the soil, these decomposing remains are further converted into organic matter.

3. How do animals that live in forests help in their growth and regeneration?

Forests serve as the natural habitat for a range of animals and birds. These animals and birds contribute to the regeneration of forests in the following ways:


  • Animals and birds in the forest help spread seeds for new trees to be able to sprout.
  • Animals that have died and decomposed in the forest are converted into nutrient-rich humus, which then gives plants nourishment.
  • Excreta from animals and birds also provides nourishment for growing plants.