DAV class 5 science ch 3

July 25, 2020

DAV class 5 science ch 3

FORESTS

Facts that Matter

FOREST

An area where the earth is covered mainly by a very large number of trees is called forest.

ADVANTAGES OF FORESTS

Trees take up carbon dioxide and release oxygen. Thus, they purify the air and maintain the balance in the climate.

By absorbing carbon dioxide, trees check global warming.

FOREST PRODUCTS

Wood/Timber: Wood is used for making furniture and paper. It is also used as fuel.

Medicines and Spices: Many medicinal plants are found in forests. Examples: amla, ashwagandha and brahmi.

Gums, resins and dyes: Gums are used as adhesive, food additive and medicine. Resins are used for making varnishes and paints. Many dyes are obtained from forests.

Special Leaves: Areca nut leaves are used for making disposable plates. Leaves of tendu are used for special purpose. Tendu leaves are also called green gold' in Odisha.

DEFORESTATION

Large scale cutting of forests is called deforestation.

Following are some reasons of deforestation:

More land is needed to make houses, industries and for farming,

Wood is required for construction. Trees are also cut for making many products but new trees are not planted.

How TO PROTECT FORESTS?

The Forest Conservation Act was enacted by the government in 1980. As per this rule, indiscriminate cutting of forests is a punishable offence.

Many areas in India have been converted into National Parks and Wildlife Sanctuaries. This has been done to protect the forests and wildlife.

National Park: It is a reserved land which is usually owned by the national government. No human activity is allowed in it. It receives a bigger financial support from the government.

Gir National Park in Gujarat is probably the only place where the Asiatic Lions are found.

We can contribute in following ways to conserve forests:

(a) Minimise the use of wood and wood products.

(b) Do not use products which promote destruction of forests. Do not use fur because fur is obtained from animals. Do not use items made of ivory.

Words that Matter

Deforestation: Large scale cutting of forests is called deforestation.

Afforestation: Recovering forest cover by planting trees is called afforestation. Forest: An area with high density of trees is called forest.

Global Warming: General increase in earth's temperature is called global warming.

Soil Erosion: Removal of topsoil called soil erosion.

TEXTBOOK QUESTIONS

SOMETHING TO KNOW

A. Fill in the blanks.

1. Forests serve as home to many types of …………………….. .

2. Forests absorb large amounts of …………………………..

3. Deforestation ……………………….. rainfall in the surrounding areas.

4. …………………….... is the largest bird sanctuary in Asia.

5. For early man, forests were a source of ………………………. and ……………………………….

Ans. 1. animals 2. carbon dioxide 3. reduces 4. Bharatpur 5. food and shelter.

B. Match the following.

Column I

1. resins

2. forests

3. deforestation

4. ashwagandha

5. gums

Column II

(a) cutting down of trees

(b) adhesives

(d) paint

(e) medicinal plant

Ans. 1. (d) 2. (c) 3.(a) 4. (e) 5.(b).

C. Tick () the correct option.

1. The leaf used to make disposable plates, is the

(a) tendu leaf (b) areca nut leaf (c) amla leaf (d) brahmi leaf

2. Deforestation results in

(a) soil erosion (b) flood

3. Bee wax is used to make

(a) spices (b) varnish

4. Which of the following is not a forest product?

(a) gum (b) timber (c) aswagandha (d) kerosene

5. If forests disappear, the amount of

(a) carbon dioxide, in air, will decrease

(b) oxygen, in air, will increase

(d) nitrogen, in air, will increase

Ans. 1. (b) areca nut leaf 2. (d) All of the above 3. (c) medicine 4. (d) kerosene 5. (C) carbon dioxide, in air, will increase

D. Answer the following questions in brief.

1. Name any four products that are obtained from forests.

Ans. Wood, Medicinal plants, Spices and Gum.

2. Why do some men cut trees?

Ans. Some men cut trees for their own selfish interests.

3. What is the Gir National Park famous for?

Ans. Asiatic Lion.

4. Name two migratory birds that visit Bharatpur Bird Sanctuary.

Ans. Siberian crane and Pelican.

5. What is the average temperature and annual rainfall needed for a forest to develop?

Ans. Temperature of more than 10°C and minimum rainfall of 200 mm.

E. Answer the following questions.

1. List four harmful effects of deforestation.

Ans. Harmful Effects of Deforestation :

• Reduced rainfall in the surrounding area.

• Increased levels of carbon dioxide which causes global warming.

• Decreased level of groundwater which results in shortage of drinking water.

• Increase in soil erosion which results in more frequent floods.

2. How do forests prevent soil erosion?

Ans. Roots of trees bind the topsoil. This prevents soil erosion.

3. State the importance of forests to human beings.

Ans. We get many products from forests; like wood, medicinal plants, honey, wax, resin, etc. Forests help in recharging the groundwater. Forests prevent soil erosion. Forests soak up carbon dioxide and release oxygen. Thus, forests maintain the balance in our environment.

4. Why are forests known as the 'lungs of the earth"?

Ans. Forests soak up excess carbon dioxide from the atmosphere and release carbon dioxide. This is similar to the way our lungs work while removing carbon dioxide from the blood. Hence, forests are known as the lungs of the earth.

5. How can we contribute towards protection of forests?

Ans. We can contribute in following ways to conserve forests:

• Minimise the use of wood and wood products.

. Do not use products which promote destruction of forests. Do not use fur because fur is obtained from animals. Do not use items made of ivory.

. We should plant new trees and celebrate Van Mahotsava.

VALUE-BASED QUESTIONS (VBQ)

1. Who do you think had made the better choice of purchasing the gift – Ridhi or her mother?

Ans. Ridhi's mother made the better choice of purchasing the gifts. Ridhi was also motivated by her mother to do the same.

2. Make a list of five things, used at home or school, made from wood.

Ans. Table, chair, rolling pin, sofa and door.

3. Suggest two ways by which every person can contribute towards forest conservation.

Ans. Two ways by which every person can contribute towards forest conservation:

(a) By avoiding buying wooden items.

(b) By saving paper.

SOMETHING To Do

1. Visit a national park or a wildlife sanctuary and prepare a list of ten plants and ten animals that you see there. Are these plants and animals present in the area where you live? What could be the reason?

Ans. Do it yourself.

2. Given below is a poem about how human activities can be harmful to the environment. Read this poem and write down five harmful activities of humans. Suggest some ways by which we can stop and reverse the harmful effects.

"The world is finite, resources are scarce,

Things are bad and will be worse,

Coal is burned and gas exploded,

Forests cut and soil eroded,

Wells are dry and air polluted.

Dust is blowing, trees are uprooted,

Oil is going, ores depleted,

Drains receive what is excreted,

Land is sinking, seas are rising,

Man is far too enterprising,

Fires will rage with man to fan it,

Soon we will have a plundered planet."

-K. E. Boulding

Ans. Five harmful activities of humans:

• Burning of coal.

Cutting of trees

• Oil is exploited

Ores are overused

• Water is being polluted

Some ways to stop and reverse the harmful effects:

• Planting new trees

• Save paper

• Conserve minerals

• Conserve environment

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DAV class 5 science ch 3

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