Forests Our Lifeline - Revision Notes

 CBSE Class 7 Science

Revision Notes 
Chapter – 17
Forests: our lifeline

  • Forest: Large area of land thickly covered with trees, bushes, etc.
  • We get various products from the forests around us.
  • Forest is a system comprising various plants, animals and micro-organisms.
  • In a forest, trees from the uppermost layer, followed by shrubs, the herbs to the lowest layer of vegetation.
  • Different layers of vegetation provide food and shelter for animals, birds and insects.
  • The various components of the forest are interdependent on one another.
  • The forest keeps on growing and changing, and can regenerate.
  • In the forest, there is interaction between soil, water, air and living organisms.
  • Forests protect the soil from erosion.
  • Soil helps forests to grow and regenerate.
  • Forests are the lifeline for the forest-dwelling communities.
  • Forests influence climate, water cycle and air quality.
  • Deforestation: Cutting down of trees is known as deforestation.
  • Importance of Forests:
  1. Provide timber.
  2. Purify air.
  3. Provide shelter.
  4. Prevent soil erosion.
  5. Control floods.
  6. Noise absorbers.
  • Independence of Plants and Animals in Forest:
  1. Plants and animals depends on each other to remain alive.
  2. All organisms interact with each other and their physical environment to derive energy and survive.
  • Effects of deforestation:
  1. Amount of carbon dioxide in air will increase, resulting in the increase of earth’s temperature. (Global Warming)
  2. Animals will not get food and shelter.
  3. Soil will not hold water, which will cause floods.
  4. Endanger lives and environment.
  • Conservation of Forests:
  1. Do not allow overgrazing.
  2. Promote afforestation.
  3. Protect wildlife.
  4. Control forest fires.
  • ​​​​​Food Chain: Interdependence between producers and consumers studied in form of various linkage that appears as a chain. or Interdependence of organisms which shows who eats whom.


  • Food Web: A system of interdependent food chains used to represent various relationships in organisms.