Natural Vegetation, Different Types of Forests of India
Classification of Natural Vegetation of India
The distribution of natural vegetation in India is controlled and regulated by the following factors:
- Distribution of rainfall
- Orography (altitude and slope of the region)
Based on these factors, the natural vegetation of India is broadly classified into the following categories:
- Tropical Evergreen and Semi-Evergreen Forests
- Tropical Deciduous Forests
- Tropical Thorn Forests and Scrubs
- Montane Forests
- Mangrove Forests
Tropical Evergreen and Semi-Evergreen Forests
- Constitute those parts of India which have an annual rainfall of 200 cm and above.
- Rainfall here occurs almost throughout the year with a short dry season.
- Wet and warm climate support luxuriant vegetation of all kinds- trees, shrubs and creepers giving it a multilayered structure.
- Trees do not shed leaves for a definite time period. So, the forests appear green all-round the year.
- Some of the commercially available trees are Sandal Wood, ebony, mahogany, rosewood, rubber, cinchona etc.
- Important animals in these forests are elephants, monkey lemur, deer, one-horned rhinoceros etc.
- Western coast; Western Ghats; island groups of Lakshadweep, Andaman and Nicobar; upper parts of Assam; and Tamil Nadu coast are covered with these forests.
- These are similar to Equatorial rainforests.
Tropical Deciduous Forests
- These are the most widespread and the most extensive forests of India.
- They are also known as monsoon forests.
- These are connected with those parts of India which receive annual rainfall between 200 cm and 70 cm.
- Here rainfall is seasonal in nature.
- In this forest type, trees shed their leaves for about six to eight weeks in dry summer.
- The animals found in these are: lion, tiger, pig, deer, elephant, a variety of birds, lizards, snakes, tortoise, etc.
(i) Tropical Moist Deciduous Forests
- Annual rainfall between 200 & 100 cm.
- Found in: (a) an eastern part of India- northeastern states, along with the foothills of Himalayas, (b) Jharkhand, West Orissa and Chhattisgarh, (c) on the eastern slopes of the Western Ghats.
- Examples: teak, bamboos, sal, shisham, sandalwood, khair, kusum, arjun, mulberry, etc.
(ii) Tropical Dry Deciduous Forests
- Annual rainfall between 100 & 70 cm.
- Found in: (a) the rainier parts of the peninsular plateau and (b) the plains of Uttar Pradesh and Bihar.
- Examples: teak, sal, peepal, neem etc.
Tropical Thorn Forests
- These are connected with those parts which receive rainfall less than 70 cm.
- Here, rainfall is erratic, irregular and inconsistent.
- Xerophytes dominate regions covered with the tropical thorn.
- Found in the north-western part including semi-arid areas of Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Uttar Pradesh and Haryana.
- Main plant species here are acacias (babool), palms, euphorbias, Cactus, khair, , keekar etc.
- In this vegetation type, stem, leaves and roots of plants are adapted to conserve water.
- Stem is succulent and leaves are mostly thick and small to minimize evaporation.
- Common animals here are rats, mice, rabbits, fox, wolf, tiger, lion, wild ass, horses, camels, etc.
Tropical Montane Forests
- The decrease in temperature with the rise in altitude is responsible for the corresponding change in natural vegetation.
- There exists the same hierarchy from foothills of the mountain to the top of it as is observed from tropical to tundra region.
- Mostly found in the southern slopes of Himalayas, places having high altitude in Southern and Northeastern India.
- Upto 1500 n of height, tropical moist deciduous forests exist with shesham as the main tree.
- Between 1000-2000m of height, wet temperate type of climate persist wherein evergreen broad-leaf trees like oaks and chestnut
- Between 1500-3000 m of height, temperate forests covering coniferous trees like Chir, pine, deodar, silver fir, spruce, cedar, etc.
- At higher altitudes above 3500m wet temperate grasslands are common like Merg (Kashmir), bugyals (Uttarakhand), etc.
- They get progressively stunted as they approach the snowline.
- Ultimately through shrubs and scrubs, they merge into Alpine grasslands.
- These grasslands are extensively used for grazing by nomadic tribes like Gujjars and Bakkarwals.
- At higher altitudes, some vegetation mosses and lichens form part of tundra vegetation.
- Common animals that are found in these forests are Kashmir stag, spotted deer, wild sheep, jackals, yak, snow leopard, rare red panda, sheep and goats with thich fur, etc.
- In India, there are studied under two groups: Northern Montane Forests and Southern Montane Forests.
- Northern Montane Forests: These are connected with Himalayan mountain ranges. Vegetation types are controlled by sunlight, temperature and rainfall which is described above.
- Southern Montane Forests: These are connected with hills of Nilgiris, Anaimalai and Cardamom. These are wet temperate forests which have great endemic biodiversity and these are described as Shola forests.
- Mangrove forests are connected with deltaic regions of tropical and sub-tropical zones.
- These are also known as tidal forests and littoral forests as these are connected with the inter-tidal region.
- Their biodiversity and forest density are comparable with equatorial rainforest and tropical evergreen and semi-evergreen forests.
- Mangroves are salt tolerant plants with roots being adapted to become pneumatophores (these roots emerged from the ground and grow in upward direction).
- Mangrove ecosystem is a unique ecosystem as it has tolerance for periodic flooding and dryness; and mild salinity as well.
- India has the largest cover of Mangrove forest in the world.
- Sunderban, Mahanadi, Godaveri-Krishna and Kaveri delta are most importantly covered with these forests.
- Sunderban is the largest mangrove in the world. It is famous for Sundari tree which provides durable hard timber.
- Some other example are Rhizophora, Avicennia etc.
- Palm, coconut, keora, agar, etc. also grow in some parts of the delta.
- Royal Bengal Tiger is a famous animal in these forests.
- Turtles, crocodiles, gharials, snakes, are also found in these forests.
- Bhitarkanika mangrove of Mahanadi delta is also famous for its rich biodiversity.