This PSEB 7th Class Science Notes Chapter 17 Forests: Our Lifeline will help you in revision during exams.
PSEB 7th Class Science Notes Chapter 17 Forests: Our Lifeline
→ A system made up of plants, animals, and micro-organisms are called a forest.
→ The top layer of the forest is Canopy Layer, the mid-layer is the Crown layer and the lower layer is the Understory layer.
→ Forests protect the soil from erosion.
→ Soil helps in the growth and development of trees.
→ Humus shows that nutrients from the bodies of dead plants and animals have been incorporated into the soil.
→ Forests act like green lungs and produce many products. That is why forests are so important.
→ A forest is an area whose uppermost layer is topped by trees.
→ Forests are always green.
→ A variety of animals, plants, and insects are found in forests.
→ All wild animals, herbivores or carnivores, depend on plants for food in one or the another way.
→ Forests continue to grow and develop and can regenerate.
→ Forests affect climate, water cycle, and air quality.
→ Trees, shrubs, vegetation, herbs, etc. all are found in forests.
→ According to the height of trees and plants, forests are divided into three categories:
- Canopy
- Crown
- Understory
→ Forest soil helps in regeneration.
→ Forest plants emit vapours and help bring rain and regulate the temperature of the environment.
→ Different layers of vegetation in forests provide food and shelter to animals, birds, and insects.
→ In the forest, soil, water, air, and living things have interdependence on each other.
→ Forests provide important basic necessities for communities living in forested areas.
→ Forests maintain and regulate climate, water cycle, and air quality.
→ Decomposers depend on the dead bodies of plants and animals and turn them into simple substances.
→ Deforestation causes global warming, decreases rainfall, increases pollution, and erodes soil.
→ To maintain balance in nature and maintain habitat for wild animals and plants forest plays an important role.
→ Forest: A forest is an area where there is a lot of dense vegetation, including animals, trees, bushes, and weeds that grow naturally.
→ Canopy: The top layer of tree branches forms a dense top layer of trees on earth which is called the canopy.
→ Crown layer: The layer in which the branches and trunks of trees come, is called the crown or crown layer.
→ Understory Layer: The shaded area below which there is very little light, is called the lower or understory layer.
→ Ecosystems: Living things and their environment work together to create ecosystems. Plants, animals, and microorganisms are the biological components of the ecosystem. These are divided into different categories of producers, consumers, and decomposers.
→ Food chain: In ecology, the sequence of transfer of matter and energy in the form of food from one organism to another organism is called a food chain.
For example:
→ Food Web: A food web consists of a network of many food chains. A food chain helps provide food to organisms at the next food level.
→ Afforestation: The process of planting trees on a large scale is called Afforestation.
→ Decomposers: Microorganisms that decompose the dead bodies of plants and animals into humus, are called Decomposers.
→ Erosion: In the absence of trees and plants top layer of soil is lost, This process of carrying away the topsoil by wind and water is called soil erosion.
→ Replenishment of forest: Planting a large number of plants and trees in the forest area is called forest replenishment.