12. Forests: Our Lifeline

Give Reasons for the following:

Q1. Why are forests called the lungs of the Earth?

Ans:

1. Forests absorb carbon dioxide & release oxygen through the process of photosynthesis. 
2. Oxygen is required by the animals for respiration.
3. They maintain the balance of oxygen & carbon dioxide in the atmosphere.
4. Thus, forests are called the green lungs of the Earth.

Q2. Why don't we see similar kind of trees in every forest?

Ans:

We don't see similar king of trees in every forest because:

1. Different climatic conditions lead to variations in the types of trees & other plants.
2. The types of animals also differ from forest to forest.

Q3. If we cut some trees for buildings, will it make any difference? Give reasons for your answer.

Ans:

1.  Yes, if we cut some trees for buildings, it will make a huge difference because:

1. Green plants are autotrophs that produce their own food.
2. Herbivores eat plants & other organisms eat herbivores.
3. All animals, whether herbivores or carnivores, depend ultimately on plants for food.
4. All food chains are linked. If any one food chain is disturbed, it affects other food chains.

Answer the following in short:

Q1. Who plants trees in the forests?

Ans:

1. Trees produce enough seeds.
2. Forest floor provides favourable conditions for the seeds to germinate & develop into seedlings.

Q2. What are the layers of a forest?

Ans:

The layers of the forests are the canopy, understorey & forest floor.

Q3. What products do we get from forests?

Ans:

1. Plywood, fuel wood, boxes, paper, matchsticks & furniture.
2. Gum & oils.
3. Spices, fodder for animals and medicinal plants.

Q4. What is humus?

Ans:

Humus is a dark coloured substance obtained when dead plants & animals tissues are decomposed by decomposers.

Q5. Who are decomposers?

Ans:

Decomposers are micro-organisms like fungi & bacteria that convert dead plants & animals to humus.

Q6. What is crown?

Ans:

Crown is the branchy part of a tree above the stem. The crowns of giant trees forms the canopy.

Q7. What is canopy?

Ans:

Canopy is the uppermost layer of the forest formed by the crowns of tall trees which look like a roof over the other plants.

Q8: What is understorey?

Ans:

Understory is the layer beneath the canopy, consisting of smaller trees, shrubs & young plants.

Q9. What is the forest floor?

Ans:

1. It is dark coloured spongy carpet.
2. It is covered with a layer of dead & decaying leaves, fruits, seeds, twigs & small herbs.

Q10. How do trees maintain the water cycle?

Ans:

Trees take in water from their roots and release water vapour into the air through the process of transpiration, thus maintaining the water cycle.

Answer the following:

Q1. How is forest a dynamic living entity?

Ans:

1. More variety of plants in the forest provides more food & habitat to a variety of herbivores.
2. More herbivores more carnivores & organisms depending on herbivores.
3. Wide variety of animals helps the forest to regenerate and grow.
4. Dead plants & animals are converted to humus by decomposers like bacteria & fungi.
5. This humus is nutrients to living plants. 
6. Hence forest is a dynamic living entity & nothing is a waste. 

Q2. How does canopy protect the forest floor from heavy rains?

Ans:

1. Canopy is the topmost layer of the forest formed by crown of giant trees.
2. During rainfall, the canopy intercepts the flow of raindrops.
3. Hence most of the water was comes down slowly through the branches, stems & leaves of these trees.
4. The water then flows through the shrubs & herbs, thus the raindrops do not directly hit the forest floor.

Q3. How do forests help us to get water supply & prevent soil erosion?

Ans:

1. Forests help to maintain water table throughout the year as it is a natural absosrber of rainwater.
2. Forests help in controlling floods & maintain flow of water in streams & rivers
3. Thus this helps us to get a steady supply of water.

4. Roots of trees bind the soil & hence prevent soil erosion during heavy rains.

Q4. How deforestation will be harmful to us?

Ans:

In the absence of trees:

1. The amount of carbon dioxide in air will increase leading to increase of Earth’s temperature.
2. Plants, animals & tribes living in forests will not get food & shelter.
3. There will be floods & soil erosion.
4. There will be loss of habitat & biodiversity.
5. Thus this all will endanger our life & environment.