Forest Types of India - UPSC Environment Notes

India, a land of diverse landscapes and climates, boasts an extensive array of forest types that are as rich and varied as the nation’s cultural tapestry. From the lush, tropical rainforests of the Western Ghats to the arid scrublands of Rajasthan, the country’s forests encompass a remarkable spectrum of ecosystems, each supporting unique flora and fauna. These forests not only serve as crucial habitats for wildlife but also play a vital role in sustaining ecological balance, regulating climate, and providing invaluable resources to millions of people. Understanding the diverse forest types of India is essential for appreciating the country’s natural heritage and implementing effective conservation strategies to safeguard these invaluable ecosystems for future generations.

Table of Contents

TROPICAL WET EVERGREEN FORESTS

These rainforests thrive in densely vegetated regions where annual rainfall exceeds 250cm, and the average temperature ranges from 25 to 27 degrees Celsius.
The humidity levels surpass 77%, and the dry season is notably brief.
Characterized by trees that retain their leaves throughout the year, these forests are known as Evergreen Forests.
They exhibit a towering, layered structure and remarkable density. The thick green canopy prevents sunlight from reaching the forest floor, fostering lush vegetation.
Situated primarily along the western slopes of the Western Ghats and in regions such as Arunachal Pradesh, upper Assam, Nagaland, Manipur, Mizoram, Tripura, and the Andaman & Nicobar Islands, these forests host important species like mesua, cedar, bamboo, jamun, and canes.
Despite the presence of valuable commercial species, these forests have remained largely untouched due to their dense undergrowth.

TROPICAL SEMI-EVERGREEN FOREST

These areas experience relatively drier conditions compared to the aforementioned regions.
The annual rainfall in this type of environment typically ranges between 200-250 cm, with a mean annual temperature varying from 24-27 degrees Celsius and a relative humidity of approximately 75%.
These regions are located in Assam, the lower slopes of the Eastern Himalayas, Odisha, and the Andaman Islands.
In certain locations, these areas serve as transitional zones between wet evergreen forests and deciduous forests.
Noteworthy species in these regions include semul, rosewood, kusum, Indian chestnut, champa, and others.

TROPICAL MOIST DECIDUOUS FORESTS

These regions are situated in areas with moderate annual rainfall ranging from 100-200 cm.
The mean annual temperature in these areas is around 27 degrees Celsius, with an average annual relative humidity ranging from 60-75 percent.
They are distributed as a strip along the Western Ghats, another strip along the Shiwalik range, most of Odisha, parts of West Bengal, and in the Andaman and Nicobar Islands.
The characteristic feature of these forests is that the trees shed their leaves for approximately 6-8 weeks annually, specifically during periods of insufficient moisture.
These forests are commercially valuable due to the presence of high-quality timber, making them prone to exploitation.
Key species in these regions include teak, Sal, lendi, bamboo, and others.

LITTORAL AND SWAMP FOREST

These forests are situated in and around deltas, estuaries, and creeks that are susceptible to tidal influences, earning them the names tidal or delta forests.
Specifically, swamp forests are confined to the deltas of the Ganga, Mahanadi, Krishna, and Cauvery rivers.
A distinctive feature of these forests is their ability to thrive in both fresh and brackish water environments.
Dense mangroves form in areas such as coasts, tidal creeks, backwaters, salt marshes, and mud flats.
These forests are a source of hard and durable timber, utilized for construction, building purposes, and boat-making.
Key species in these areas include Sundri, agar, bhendi, Rhizopora, canes, and palms.

DRY TROPICAL FOREST

Tropical Dry Evergreen Forests:

On the coasts of Tamil Nadu, there are regions experiencing an annual rainfall of approximately 100 cm, primarily from the North Eastern monsoon winds during October-December.
The mean annual temperature hovers around 28 degrees Celsius, and the average humidity is about 75%.
Key species in these areas include jamun, ritha, tamarind, neem, among others.

Tropical Dry Deciduous Forests:

Similar to moist deciduous forests, these shed their leaves during the dry season and receive rainfall ranging from around 100-150 cm per annum.
Representing a transitional type, they give way to moist deciduous forests on the wetter side and degenerate into thorn forests on the drier side.
They are found along the foothills of the Himalayas to Kanniyakumari, excluding Rajasthan, Western Ghats, and West Bengal.
Noteworthy species include teak, tendu, bamboo, sal, etc. These forests are among the most commercially exploited in India.

Tropical Thorn Forests:

These forests thrive in areas characterized by low rainfall (less than 75 cm), low humidity (less than 50%), and high temperatures ranging from 25-30 degrees Celsius.
The trees are low and widely scattered, with prominent species like acacias and common Indian wild dates.
They are found in the northwestern parts of the country, including Rajasthan, southwestern Punjab, western Haryana, Kuchch, and parts of Saurashtra.
Additionally, they grow along the leeward side of the Western Ghats. Important species in these forests include neem, babul, etc.

Montane Sub-Tropical Forests:

Sub-tropical Broad-Leaved Hill Forests:

Located in the Eastern Himalayas to the east of 88 degrees E longitude, at altitudes ranging from 1000-2000m, where the mean annual rainfall is 75-125 cm.
The average annual temperature is 18-21 degrees Celsius, and the average humidity is 80%.
Evergreen oaks and chestnuts predominate, with some ash and beech.
Sals and pines may occur on the lower and higher margins, respectively, and climbers and epiphytes are common.
Found in Nilgiri and Palni Hills, Mahabaleshwar, summits of Satpura and Maikal range, and highlands of the Aravali range.

Sub-tropical Moist Pine Forests:

Situated at elevations of 1000-2000m above sea level in the western Himalayas between 73 degrees East and 88 degrees E longitudes.
Parts of Arunachal Pradesh, Manipur, Naga Hills, and Khasi Hills are covered with such forests.
The dominant tree species in this region is Chir or Chil, and these forests are known for timber production as well as the production of resin and turpentine.

Sub-tropical Dry Evergreen Forests:

Found in the Bhabar belt, the Shiwalik, and the western Himalayas up to 1000m above sea level.
The rainfall here ranges from 50-100 cm, with summers being sufficiently hot and winters cold enough for the occurrence of frosts.
The most predominant species include olive, acacia, pistachio.

MONTANE TEMPERATE FOREST

Montane Wet Temperate Forests:

These forests thrive at elevations of 1800-3000m, where the mean annual rainfall ranges from 150-300cm.
The mean annual temperature is approximately 11-14 degrees Celsius, with an average relative humidity exceeding 80%.
Mainly found in the higher hills of Tamil Nadu and Kerala, to the east of 88 degrees in the Himalayas, hills of West Bengal in the Himalayas, hills of West Bengal, Assam, Arunachal Pradesh, Sikkim, and Nagaland.
Notable species in these forests include deodar, Indian chestnut, birch, plum, oak, and hemlock.

Himalayan Moist Temperate Forests:

Occurring in the temperate zone between 1500-3300m, where annual rainfall varies from 150-250cm.
These forests cover the entire range in Kashmir, Himachal Pradesh, Uttarakhand, and Sikkim.
Dominated by trees such as pines, cedars, silver firs, and spruce, these forests provide fine wood widely used in construction, timber, and railway sleepers.

Himalayan Dry Temperate Forests:

Predominantly coniferous forests with xerophytic shrubs, featuring main trees like deodar, oak, ash, maple, and olive.
Found in the inner dry ranges of the Himalayas where the southwest monsoon is feeble, and precipitation is below 100cm.
These areas are located in Ladakh, Lahul, Chamba, Kinnaur, Garhwal, and Sikkim.

Alpine Forests:

Beginning at an elevation above 3000m and extending up to the region just below the snowline, these forests are common in both the main Himalayan regions and the barren cold deserts of the Trans-Himalaya.
Low alpine grasslands are prevalent, with vegetation not exceeding a height of 1.5m. Climatic conditions range from sub-arctic to arctic, with snow covering the ground for over 5 months a year.
The growing season for plants is stunted, and pastures are grazed by migratory cattle in summer.
The vegetation mainly comprises black juniper, drooping juniper, honeysuckle, and willow.

FAQs – DIFFERENT TYPES OF FORESTS

Q1: What defines Tropical Wet Evergreen Forests, and where are they primarily located?

A1: Tropical Wet Evergreen Forests thrive in densely vegetated areas with annual rainfall exceeding 250cm and an average temperature ranging from 25 to 27 degrees Celsius. Found primarily along the western slopes of the Western Ghats and regions like Arunachal Pradesh, upper Assam, Nagaland, Manipur, Mizoram, Tripura, and the Andaman & Nicobar Islands.

Q2: What characterizes the vegetation in Tropical Wet Evergreen Forests?

A2: These forests are characterized by trees that retain their leaves throughout the year, earning them the name Evergreen Forests. The structure is towering, layered, and dense, preventing sunlight from reaching the forest floor and fostering lush vegetation.

Q3: Why have Tropical Wet Evergreen Forests remained largely untouched despite the presence of valuable species?

A3: Despite hosting valuable commercial species like mesua, cedar, bamboo, jamun, and canes, these forests have remained largely untouched due to their dense undergrowth.

Q4: How do Tropical Semi Evergreen Forests differ from Tropical Wet Evergreen Forests?

A4: Tropical Semi Evergreen Forests experience relatively drier conditions with annual rainfall between 200-250 cm, a mean temperature of 24-27 degrees Celsius, and around 75% relative humidity.

Q5: Where are these forests typically located, and what notable species can be found in them?

A5: Situated in Assam, lower slopes of the Eastern Himalayas, Odisha, and the Andaman Islands, these forests serve as transitional zones between wet evergreen and deciduous forests. Noteworthy species include semul, rosewood, kusum, Indian chestnut, and champa.

Q6: What are the key characteristics of Tropical Moist Deciduous Forests?

A6: Tropical Moist Deciduous Forests are found in areas with moderate annual rainfall (100-200 cm), a mean temperature of around 27 degrees Celsius, and an average relative humidity of 60-75 percent.

Q7: Where are these forests distributed, and why are they commercially valuable?

A7: These forests are distributed along the Western Ghats, Shiwalik range, Odisha, West Bengal, and the Andaman and Nicobar Islands. They yield valuable timber, making them commercially exploitable. Key species include teak, Sal, lendi, and bamboo.

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Forest Types of India – UPSC Environment Notes