Revision Notes: Natural Vegetation in India

• 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.
• Two types: Moist Deciduous & Dry Deciduous

(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.

• 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.
• Up to 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

•  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.