Question

explain the type of forests on the basis of altitude

Answer 1

) Tropical moist evergreen forests,
(i) Tropical moist semi-evergreen forests, and
(iii) Tropical moist deciduous forests.
(iv) Littoral and swamp forests.


Tropical moist evergreen forests:
These are also called tropical rain forests. In India such forests are found in very wet regions receiving more than 250 cm average annual rainfall. These are climatic forests having luxuriantly growing lofty trees which are more than 45 metres in height. The shrubs, lianas (woody climbers) and epiphytes are abundant because of high rainfall. These forests are found in Andaman and Nicobar Islands, Western coasts and parts of Karnataka (N. Canara), Annamalai hills (Koorj), Assam and Bengal. The detail account of this is given in the description of mesophytes.
(ii) Tropical moist semi-evergreen forests:
These forests are found along the western coasts, eastern Orissa and upper Assam where annual rainfall is between 200 and 250 cm. They are characterised by giant and luxuriantly growing intermixed deciduous and evergreen species of trees and shrubs. The important plants in these forests are the species of Terminalia, Bambusa, Ixora, Dipterocarpus, Garcinia, Sterculia, Mallotus, Calamus, Albizzia, Elettaria, Pothos, Vitis, Shorea, Cinnamomum, Bauhinia, Albizzia, etc. Orchids, ferns, some grasses and several other herbs are also common.
(iii) Tropical moist deciduous forests:
These cover an extensive area of the country receiving sufficiently high rainfall (100 to 200 cm) spread over most of the year. The dry periods are of short duration. Many plants of such forests show leaf-fall in hot summer.
The forests are found along the wet western side of the Deccan plateau, i.e. Mumbai, N-E. Andhra, Gangetic plains and in some Himalayan tracts extending from Punjab in west to Assam valley in the east. The forests of Southern India are dominated by Teak (Tectona grandis), Terminalia paniculata, T. bellerica, Grewia tilliaefolia, Dalbergia latifolia, Lagerstroemia, Adina cordifolia, etc. are the other common species in forests of South India. In north, they are dominated by shal (Shorea robusta).
Some other common associates of shal are Terminalia tomentosa, Dellenia species, Eugenia species, Boswellia species and Mallotus philippensis. These forests produce some of the most important timbers of India. Grasses become important both in seral stages and in the areas under fire.
(iv) Littoral and Swamp Forests:
Littoral and Swampy forests include the following types:
(1) Beach forests
(2) Tidal forests or Mangrove forests
(3) Fresh water swamp forests.
Beach Forests:
The beach forests are found all along the sea beaches and river deltas. The soil is sandy having large amount of lime and salts but poor in nitrogen and other mineral nutrients. Ground water is brackish, water table is only a few metres deep and rainfall varies from 75 cm to 500 cm depending upon the area. The temperature is moderate. The common plants of these forests are Casuarina equisetifolia, Borassus, Phoenix, Manilkara littoralis, Callophyllum littoralis, Pandanus, Thespesia, Barringtonia, Pongamia, Cocos nucifera, Spinifex littoreus and a number of twiners and climbers.
Tidal or Mangrove forests:
Tidal forests grow near the estuaries or the deltas of rivers, swampy margins of Islands and along sea coasts. The soil is formed of silt, silt-loam or silt-clay and sand. The plants are typical halophytes which are characterised by presence of prop roots with well developed knees for support and pneumatophores and viviparous germination of seeds.
Tidal forests one distinguished into the following four types with overlapping constituent species:
(i) Tree mangrove forests
(ii) Low mangrove forests,
(iii) Salt water forests and
(iv) Brackish water forests.