Tropical Evergreen Forest:
Also called Tropical rain forests. Found in the western slope of the western ghats(especially the malabar coast), hills of the northeastern region and the Andaman & Nicobar Island. Also Silent Valley in Kerala. Found in warm & humid areas. Annual precipitation of over 200 cm. Mean annual temperature above 22 degree celsius. Well stratified i.e. arranged in different layers – the lower strata consists of mosses, ferns & grasses; the middle layer has a dense growth of shrubs & the topmost layer consists of the large trees. Termites, fungi, mushrooms etc. grow on the ground layer. Warm temperature and high availability of moisture facilitate rapid breakdown (decomposition) of the dropped leaves, twigs etc. releasing the nutrients rapidly. These nutrients are immediately taken up by the mycorrhizal roots of the trees. Trees reach great heights up to 60m or above. Due to continuous rainfall throughout the year, the trees do not shed their leaves all at the same time & hence such forests are called as evergreen forests. Species – Rosewood, Mahogony, Aini, Ebony etc. Semi-evergreen forest – mixture of evergreen and moist deciduous trees. Main species are White cedar, Hollock & Kail. The tropical evergreen forest in Brasil is so enormous that it is like the lungs of the earth. Shifting cultivation & colonial exploitation of timber, especially during the first and second world war have seriously depleted these forests.
Tropical Deciduous Forest:
Also called Monsoon forests. Most widespread forests in India. Receive rainfall between 70-200 cm. The characteristic feature of deciduous vegetation is that the trees shed their leaves for six to eight weeks at the beginning of the summer season. Divided in to moist and dry deciduous on the basis of availability of water.
Moist Deciduous Forest:
These forest occur where the rainfall is around 100-200 cm. Found in the northeastern states along the foothills of Himalayas, eastern slopes of the western ghats and orissa. Main species- Teak (tectona grandis), sal, shisham, hurra, mahua, amla, semul, kusum & sandalwood etc.
Dry Deciduous Forest:
These forest occur where the rainfall is around 70-100 cm. Found in the plains of Uttar Pradesh, Bihar & West Bengal, most of the areas of the Deccan plateau and in the rain shadow areas of western ghats. Main species- Tendu, palas, amaltas, bel, khair, axlewood etc.
Tropical Thorn Forest:
Receive rainfall less than 50 cm. Consist of variety of grasses and shrubs. Scrub Vegetation – plants remain leafless for most part of the year. Found in semi-arid areas of south west Punjab, Haryana, Rajasthan, Gujarat, M.P. & U.P. Main species- babool, ber, wild date palm. khair, neem, khejri, palas etc. Tussocky grass grows upto a height of 2 m as undergrowth.
Also called tidal or deltaic forest. The mangrove forests develop when there is an intermixing of the freshwater of the rivers & the saline water of the seas. Such an area is called brackish water habitat. play a crucial role in supporting the ecological balance. It can regenerate and propagate very fast. These have an important role in arresting tidal waves and minimizing the impact of natural disasters like tsunamis and also to arrest coastal erosion. As compared to terrestrial trees, mangroves are known to absorb carbon-dioxide faster and are termed as ‘carbon sinks’. Mangrove forests are regarded as the most productive wetlands in the world on account of the large quantities of organic and inorganic nutrients released in the coastal waters by these ecosystems. Two sites – Chilika Lake (Orissa) & Keoladeo National Park (Bharatpur) are protected as water-fowl habitats under the Convention of Wetlands of International Importance (Ramsar Convention). They also act as nurseries for fin fish, shell fish, crustaceans and molluscs. Mangroves are highly developed in Andaman & Nicobar island, Sunderbans of west bengal.
A National Park is an area dedicated for the conservation of wildlife along with its environment. It is also meant for enjoyment through tourism but without impairing the environment. Grazing of domestic animals, all private rights and forestry activities are prohibited within a National Park. Each National Park usually aims at conservation specifically of some particular species of wildlife along with others.
National Parks of our country are-
Name of National Park Important Wildlife Kaziranga (Assam) One-horned Rhino Gir National Park (Gujarat) Indian Lion Dachigam (J&K) Hangul Bandipur (karnataka) Elephant Periyar (Kerala) Elephant, Tiger Kanha (M.P.) Tiger Corbett (Uttarakhand) Tiger Dudwa (U.P.) Tiger Ranthambore (Rajasthan) Tiger Sariska (Rajasthan) Tiger
Wildlife sanctuaries are also protected areas where killing, hunting, shooting or capturing of wildlife is prohibited except under the control of highest authority. However, private ownership rights are permissible and forestry operations are also permitted to an extent that they do not affect the wildlife adversely.
wildlife sanctuaries of our country are-
Name of Sanctuary Major Wildlife Ghana Bird Sanctuary (Rajasthan) 300 species of birds (including migratory) Hazaribagh Sanctuary (Bihar) Tiger, Leopard Sultanpur Bird Sanctuary (Harayana) Migratory birds Nal Sarovar Bird Sanctuary (Gujarat) Water birds Abohar Wildlife Sanctuary (Punjab) Black buck Mudamalai Wildlife Sanctuary (Tamil Nadu) Tiger, Elephant, Leopard Vedanthangal Bird Sanctuary (Tamil Nadu) Water birds Jaldapara Wildlife Sanctuary (West Bengal) Rhinoceros, elephant, Tiger Wild Ass Sanctuary (Gujarat) Wild ass, wolf, nilgai, chinkara