(Environment & Ecology) INDIAN FOREST TYPES - Dry Tropical, Montane Sub Tropical, Moist Tropical & Alpine Forests

ENVIRONMENT AND ECOLOGY


INDIAN FOREST TYPES

India has a diverse range of forest: from the rainforest of Kerala in the south to the alpine pastures of Ladakh in the north, from the deserts of Rajasthan in the west to the evergreen forests in the north-east. Climate, soil type, topography, and elevation are the main factors that determine the type of forests. Forests are classified according to their nature and composition, the type of climate in which they thrive, and its relationship with the surrounding environment. Indian forests can be divided into six broad types, with a number of sub types:

Moist Tropical


A. Wet evergreen forests:  These are found in the south along the Western Ghats and the Nicobar and Andaman Islands and all along the north-eastern region. It is characterized by tall, straight evergreen trees that have a buttressed trunk or root on three sides like a tripod that helps to keep a tree upright during a storm.

B.  Semi-evergreen forests: These are found along the Western Ghats adjoining wet ever green forests i.e. , in Assam and lower attitudes of Eastern Himalayas, Orissa, Malabar Coast and Andaman’s. Rainfall varies from 200-250 cm. Such forests have a mixture of the wet evergreen trees and the moist deciduous trees. The forest is dense and is filled with a large variety of trees of both types.

C.  Littoral and swamp forests: Such type of forests are found along the Andaman and Nicobar Islands and the delta area of the Ganga and the Brahmaputra. It consists mainly of Whistling pines, Mangrove, Palms, and Bulletwood. They have roots that consists of soft tissue so that the plant can breathe in the water.

The littoral forests occur all along the sea coasts and along the sandy bars of deltas of the large rivers, whereas, the tidal swamp forests are further divided into 5 types:

(i)  Mangrove scrub,
(ii) Mangrove forests,
(iii) Salt water mixed forests,
(iv) Brackish water mixed forests and
(v) Palm Swamp. The Sunder bans (W.B.) and the Bhitarkanika (Orissa) mangrove forests come under this category.

D.  Moist deciduous forests: These forests are found throughout India in the regions of typical rainfall range of 150-200 cm annually except in the western and the north-western regions. The trees have broad trunks, are tall and have branching trunks and roots to hold them firmly to the ground. Some of the taller trees shed their leaves in the dry season. There is a layer of shorter trees and evergreen shrubs in the undergrowth. These forests are dominated by Sal and Teak, along with mango, Bamboo, and Rosewood.

Dry Tropical Forests


A.  Dry deciduous forests: These forests are found throughout the northern part of the country except in the North-East. It is also found in Madhya Pradesh, Gujarat, Andhra Pradesh, Karnataka and Tamil Nadu. All the forests of North India i.e. , Bihar, UP., Punjab, Haryana of non-teak and teak bearing types come under this. This canopy of the trees does not normally exceed 25 meters. The common trees are the Sal, a variety of Acacia, and bamboo.

B.  Thorn Forests: This type is found in areas with black soil: North, West, Central, and South India having 25-75 cm of rainfall every year. The trees do not grow beyond 10 meters. Spurge, caper, and cactus are typical of this region

C.  Dry evergreen: These are found along the Andhra Pradesh and Karnataka coast. It has mainly hard-leaved evergreen trees with fragrant flowers, along with a few deciduous trees. These are dense forests of curvaceous leaved evergreen forests.

Montane Sub Tropical Forests


A.  Dry evergreen forests: These normally have a prolonged hot and dry season and a cold winter. It generally has evergreen trees with Shining leaves that have a varnished look. Some of the  more common ones are the pomegranate, olive, and oleander. These forests are found in the Shivalik Hills and foothills of the Himalayas up to a height of 1000 meters.

B.  Pine forests: These are found in the steep dry slopes of the Shivalik Hills, Western and Central Himalayas, Khasi, Naga, and Manipur Hills. The trees predominantly found in these areas are the Chir, Oak, Rhododendron, and pine. In the lower regions Sal, sandal, Amla, and Laburnum are found.

Montane Temperate Forests


A. Wet Montane temperate forests: These occur  in the North and the South. In the North, it is found in the region to the east of Nepal into Arunachal Pradesh, at a height of 1800-3000 meters, receiving a minimum rainfall of 200 cm. In the South, it is found in parts of the Nilgiri Hills, the higher reaches of Kerala. The forests in the northern region are denser than in the South. This is because over time the original trees have been replaced by fast-growing varieties such as the Eucalyptus. Rhododendrons and a variety of ground flora can be found here. In the North, there are three layers of forests: layer has mainly coniferous, the middle layer has deciduous trees such as the oak and the lowest layer is covered by Rhododendron and Champa.

B. Moist Montane temperate forests: This type spread from the Western Himalayas to the Eastern Himalayas. The trees found in the western section are broad-leaved oak, brown oak, Walnut, Rhododendron, etc. In the Eastern Himalayas, the rainfall is much heavier and therefore the vegetation is also more lush and dense. There are a large variety of broad-leaves trees, ferns, and bamboo. Coniferous trees are also found here, some of the varieties being different from the ones found in the South.

C. Himalayan Dry Temperate Forests: This type of forest is found mainly in Lahaul, Kinnaur, Sikkim, and other parts of the Himalayas. There are predominantly coniferous trees that are not too tall along with broad-leaved trees such as the oak, maple, and ash. At higher elevation, Fir, Juniper, Deodar, and chilgoza can be found.

Sub Alpine Forests


These extend from Kashmir to Arunachal Pradesh between 2900 to 3500 meters. In the Western Himalayas, the vegetation consists mainly of Juniper, Rhododendron, Willow, and Black Currant. In the eastern and high humidity the timberline in this part is higher than that in the West. Rhododendron of many species covers the hills in these parts.

Alpine


Moist alpines: These are found all along the Himalayas and on the higher hills near the Myanmar border. It has a low scrub, dense evergreen forest, consisting mainly of rhododendron and birch. Mosses and ferns cover the ground in patches. This region receives heavy snowfall.

Dry alpines: These are found from about 3000 meters to about 4900 meters. Dwarf plants predominate, mainly the black juniper, the drooping juniper, honeysuckle, and willow.

IMPORTANCE OF FORESTS


  • The trees around us are extremely important and have always been necessary for improving the human condition – both during its life and after harvest. It is not a stretch to believe that without trees we humans would not exist on this beautiful planet.
  • Forests are commonly referred to as lungs of the earth. It is primarily because of the presence of variety of plants which due to their high density produce massive amount of Oxygen which enables other organisms to breathe. Forests of one acre provided over 6 tons of Oxygen every year.
  • Forests provide home to diverse animal and plants species, which not only provide bio-diversity on earth, but each species has the important role in the ecosystem.
  • About 25% of all the medicines that are produced originate from rainforest plants. For example Curare (toxic plant) comes from a tropical vine, and is used as an anaesthetic and to relax muscles during surgery. Similarly Quinine is derived from the ‘Cinchona Tree’ which is used to treat Malaria.
  • Forest provide timber, which is used for building house, furniture etc.
  • Forests are the most important components of earth’s ecosystem as it prevents soil erosion, maintains water cycle, check global warming etc. Without all these roles performed by forests, the earth would be uninhabitable.
  • Wildlife tourism generates  lots of capital , which in turn increases the revenue of the government.
  • Forests still harbor various species of living organisms which are still being discovered. Each animal insects and plants contain its individual genetic material that has been evolving for thousands of years. Protecting the forests not only preserves a process of life that started billions of years ago but it also gives us missing clues to various riddled aspects of life itself.


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