Page 1 - 2.Lesson notes-Deforestation causes and consequences

SAI International School
Subject – Biology, Class-VIII
Topic-Conservation of plants and animals
Sub topic- Deforestation: Causes and consequences
Module -31
Lesson Notes

Deforestation: Cutting of trees in large scale and clearing of forest area is called
deforestation.

Causes of deforestation: The manmade causes are

Procuring land for cultivation.

Building roads, dams, houses and factories etc.

Making furniture and paper.

Using wood as fire wood.

The natural causes are

Forest fire

Severe drought

Volcanic irruptions

Consequences of deforestation: The consequences of deforestation are

1. Increased level of carbon dioxide and global warming

Plants utilize carbon dioxide and produce oxygen by photosynthesis. Number of trees is
reduced due to deforestation, the amount of Carbon dioxide increases. Carbon dioxide
traps heat of sun light leading to increase in average temperature of earth called global
warming.

2. Increases incidence of drought

Due to global warming, water cycle gets disturbed. It causes less rainfall and increases
the incidence of drought.

3. Desertification