Natural Vegetation

Question 1

Explain the term natural vegetation

Answer 1

It refers to the plant cover that has grown on their own without any interference by humans and has not been disturbed over a long period of time so to allow its individual species to adjust them fully to the climate and soil condition.

Question 2

What are the significances of forests in maintaining the ecological balance?

Answer 2

• Helps in regulating or moderating the climate.
• Helps in controlling soil erosion by binding the soil with their roots.
• Helps in recharging underground water by avoiding surface run-off hence also reduces chances of flood. - Helps in increasing the fertility of the soil by adding humus.
• Purifies the air by absorbing carbon dioxide hence controls atmospheric pollution.
• Provides protected and natural habitat for wild animals.
• Helps in providing rainfall through transpiration.

Question 3

What is Van Mahotsav?

Answer 3

This movement was launched in 1950 to make people aware of the importance of planting trees. Every year free saplings are distributed during the monsoon season in the first week of July. These saplings are planted in schools, colleges, alongside of roads and areas affected by soil erosion.

Question 4

Explain with reference to climate why tropical evergreen forests are evergreen

Answer 4

This region experiences high temperature accompanied with high rainfall. As well as there is high humidity almost 77% throughout the year.

Question 5

Why are tropical evergreen forests not of great commercial importance?

Answer 5

The trees grow in mixed stands with thick undergrowth and the trees are difficult to cut as the timber is very hard.

Question 6

How do tropical evergreen forests affect the climate of the region?

Answer 6

Forests help in regulating or moderating the climate. It also helps in providing rainfall through transpiration.

Question 7

What are the characteristic features of trees in tropical evergreen forests?

Answer 7

• The trees are tall with a height more than 45m. - The trees do not have fixed time to shed their leaves hence appear evergreen throughout the year. - The trees have less economical value as they are difficult to cut as the timber is hard. - The trees are broadleaved that forms a canopy which does not allow the sunlight to reach the ground.

Question 8

Why do trees in tropical deciduous forests shed their leaves?

Answer 8

Trees shed their leaves together almost for six to eight weeks during spring and early summers to conserve the water during the dry season.

Question 9

Why are tropical deciduous forests commercially the most exploited?

Answer 9

Trees are found in pure stands, the forest is less dense, and they provide good quality timber.

Question 10

Why does vegetation change with altitude in mountain forests?

Answer 10

Vegetation in mountainous regions varies according to the elevations since temperature and rainfall also change.

Question 11

Why are mountain forests absent in the Western Ghats?

Answer 11

Mountain forests are absent in the Western Ghats because the height of these mountains rarely exceeds 1500m.

Question 12

Why are trees absent above a certain height in mountain forests?

Answer 12

Trees cannot grow beyond the snow line as this region is permanently snow-covered and the frozen sub-soil does not support tree growth.

Question 13

How are mangrove forests ecologically important?

Answer 13

• The tangled roots also provide excellent conditions for nesting and breeding of a variety of marine fishes, birds, and aquatic animals. - The trees along the coast act as a buffer to reduce the impact of sea waves or tsunamis, hence preventing soil erosion.

Question 14

Why do mangrove forests need breathing roots?

Answer 14

Mangrove forests need breathing roots because they have specialized breathing roots known as Pneumatophores that contain small pores which enable the tree to respire during high tide.

Question 15

Name two important species of trees found in mangrove forests.

Answer 15

Keora, Amur, Sundari, Rhizophora

Question 16

How do thorn forests adapt to environmental challenges?

Answer 16

• Trees are xerophytic in nature. - Forests include coarse grasses, thorny bushes which are widely scattered. - The leaves are modified into spines to reduce transpiration rate. - They have long roots in search of underground water. - The trees remain leafless for most parts of the year to conserve water. - Trees have succulent and thick fleshy stem to store water.

Question 17

Where do thorn forests grow and why?

Answer 17

Thorn forests grow in Northwest India including Western Rajasthan, Gujarat, M.P, Chhattisgarh, Central Maharashtra, Karnataka, Andhra Pradesh etc. These regions experience very scanty rainfall i.e. below 50cm.

Question 18

Name two trees of economic importance found in thorn forests and state their use.

Answer 18

Babool - The gum of tree has immense medicinal value. Kikar - It provides timber for construction and furniture making. Its leaves are used as fodder.

Question 19

Under what conditions do thorn forests grow?

Answer 19

Climatic conditions - Temp-25-27⁰C Rainfall-below 50cms Humidity-Less than 47%

Question 20

What is Social forestry?

Answer 20

Social Forestry - It refers to the management and protection of the forest and afforestation on barren land with the purpose of helping in environmental, social, and rural development.

Question 21

What is deforestation?

Answer 21

Deforestation - It is indiscriminate cutting down of trees over a large area.

Question 22

What is Agro-forestry?

Answer 22

Agro-forestry - It is part of social forestry and represents the intermediate stage between forestry and agriculture. It refers to the sustainable system of managing a piece of land through combined production of agricultural crops, forests, and animal rearing.

Question 23

State the measures to conserve forests.

Answer 23

Afforestation or reafforestation to increase the forest cover. Stop indiscriminate felling of trees. Using alternative sources of energy (Solar, Wind, Hydel power, Bio-gas) instead of fuelwood. Strict laws should be made to restrict deforestation. People should be educated and encouraged to participate in Van-Mahotsav. Establishing corridors between the reserved forests that allow easy movement of wild animals.

Question 24

Differentiate between Afforestation and Reafforestation

Answer 24

Afforestation: It is the scheme of planting new trees on barren land. Reafforestation: It is the restoration of forest on land where the trees are indiscriminately cut. The newly planted forests are carefully supervised. Two saplings are planted to replace every cut tree.

Question 25

Why are tropical evergreen forests evergreen?

Answer 25

The trees shed their leaves in different periods of the year.

Question 26

Why are tropical deciduous forests commercially exploited?

Answer 26

The trees are commercially most exploited because they provide good quality timber.

Question 27

Why does vegetation change with altitude in mountain forests?

Answer 27

Vegetation in mountainous regions varies according to the elevations since temperature and rainfall also change.

Question 28

Why are mountain forests absent in the Western Ghats?

Answer 28

Mountain forests are absent in the Western Ghats because the height of these mountains rarely exceeds 1500m.

Question 29

Why are trees absent above a certain height in mountain forests?

Answer 29

Trees cannot grow beyond the snow line as this region is permanently snow-covered and the frozen sub-soil does not support tree growth.

Question 30

How are mangrove forests ecologically important?

Answer 30

Mangrove forests are ecologically important because they provide excellent conditions for nesting and breeding of a variety of marine fishes, birds, and aquatic animals. Additionally, they act as a buffer to reduce the impact of sea waves or tsunamis, hence preventing soil erosion.

Question 31

Why do mangrove forests need breathing roots?

Answer 31

Mangrove forests need breathing roots because they have specialized breathing roots known as Pneumatophores that contain small pores which enable the tree to respire during high tide.

Question 32

What are two important species of trees found in mangrove forests?

Answer 32

Two important species of trees found in mangrove forests are Keora and Sundari.

Question 33

How do thorn forests adapt to environmental challenges?

Answer 33

Thorn forests adapt to environmental challenges by being xerophytic in nature, having long roots in search of underground water, having modified leaves into spines to reduce transpiration rate, remaining leafless for most parts of the year to conserve water, and having succulent and thick fleshy stems to store water.

Question 34

Where do thorn forests grow and why?

Answer 34

Thorn forests grow in regions such as Northwest India including Western Rajasthan, Gujarat, M.P, Chhattisgarh, Central Maharashtra, Karnataka, Andhra Pradesh, etc. These regions experience very scanty rainfall, usually below 50cm.

Question 35

Name two trees of economic importance found in thorn forests and state their use.

Answer 35

Two trees of economic importance found in thorn forests are Babool and Kikar. Babool’s gum has immense medicinal value, and Kikar provides timber for construction and furniture making. Additionally, Kikar’s leaves are used as fodder.

Question 36

Under what conditions do thorn forests grow?

Answer 36

Thorn forests grow under specific climatic conditions, including a temperature range of 25-27⁰C, rainfall below 50cms, and humidity less than 47%.