NATURAL VEGETATION & CLIMATE

NATURAL VEGETATION & CLIMATE.

Introduction. Natural vegetation refers to the plant life that grows in a particular region without any human intervention. It encompasses a diverse range of flora, including trees, shrubs, grasses, and other vegetation types, which have adapted to the climate, soil, and other environmental conditions of their habitat over time. Natural vegetation plays a crucial role in maintaining ecological balance, supporting wildlife habitats, conserving soil and water, and influencing local climates. Understanding natural vegetation is essential for environmental conservation, sustainable land management, and biodiversity preservation. By gaining a deeper understanding of natural vegetation, we can appreciate its beauty, value, and importance in maintaining the delicate balance of our planet's ecosystems..

There are various types of natural vegetation shown in the below given flowchart. We will discuss about these in the upcoming slides.

Moist Tropical Forest.These forests are divided among the following sub-divisions. Tropical Wet Evergreen Forests: Also known as tropical rainforests, these forests experience high rainfall (over 2500 mm annually) and maintain green foliage throughout the year. They are typically found in the Western Ghats, parts of northeastern India, and the Andaman and Nicobar Islands. Tropical Semi-Evergreen Forests: These forests have slightly less rainfall compared to wet evergreen forests, usually between 2000 to 2500 mm annually. They are characterized by a mix of evergreen and deciduous tree species and are found in regions with a slightly drier climate, such as parts of the Western Ghats and northeastern India. Tropical Moist Deciduous Forests: These forests experience distinct wet and dry seasons, with annual rainfall ranging from 1000 to 2000 mm. They are characterized by a mix of deciduous trees that shed their leaves during the dry season. Tropical moist deciduous forests are widespread in central India, parts of the Eastern Ghats, and parts of the northeastern states. Tropical Dry Deciduous Forests: These forests occur in regions with a pronounced dry season and receive annual rainfall between 700 to 1000 mm. The vegetation consists of deciduous trees adapted to seasonal drought conditions. They are found in areas such as the Deccan Plateau, parts of Rajasthan, and parts of central India. Littoral and Swamp Forests: Found along the coastal areas and in swampy regions, these forests are influenced by tidal fluctuations and are characterized by mangrove species, palms, and other halophytic (salt-tolerant) vegetation. They are vital for coastal protection, biodiversity, and fisheries. Important examples include the Sundarbans in West Bengal and mangrove forests along the coasts of Gujarat, Maharashtra, Tamil Nadu, and the Andaman and Nicobar Islands..

Tropical Dry Deciduous Forests: These forests are characterized by a mix of deciduous trees that shed their leaves during the dry season to conserve moisture. They are found in regions with a pronounced dry season and receive annual rainfall between 700 to 1000 mm. Tropical dry deciduous forests are widespread in central India, parts of the Eastern Ghats, and parts of the northeastern states. Tropical Dry Evergreen Forests: These forests experience a milder dry season compared to tropical dry deciduous forests and retain a significant portion of their foliage throughout the year. They are found in regions with a moderate dry season and receive annual rainfall between 1000 to 2000 mm. Tropical dry evergreen forests are primarily located in the rain shadow areas of the Western Ghats and parts of northeastern India. Tropical Thorn Forests: Also known as tropical thorn scrub forests or tropical dry thorn forests, these ecosystems are found in arid and semi-arid regions with low and erratic rainfall. Vegetation in these forests is characterized by drought-resistant shrubs, thorny bushes, and small trees adapted to survive in harsh conditions. Examples of tropical thorn forests can be found in parts of Rajasthan, Gujarat, Maharashtra, and some parts of southern India..

Montane Temperate Forests. Montane Wet Temperate Forests:-This Variety of forests grows at a height of 1800 to 3000m above sea level In area where the mean annual rainfall is 150am to 300cm, the mean annual temperature is about 11’C to 14’C and the average relative humidity is over 80 percent. This is mainly found in the higher hills of Tamil Nadu and Kerala, in the Eastern Himalayan region to the east of 88’E longitude including the hills of West Bengal, Assam, Arunachal Pradesh, Sikkim and Nagaland. Himalayan Moist Temperate Forests: These forests occur in the middle to higher elevations of the Himalayas and are characterized by a mix of coniferous and broad-leaved trees. Species like oak, rhododendron, fir, spruce, and pine are common. These forests receive moderate to high rainfall and support diverse flora and fauna. They are found in regions such as Himachal Pradesh, Uttarakhand, and parts of Arunachal Pradesh and Sikkim. Himalayan Dry Temperate Forests:- These are predominantly coniferous forests with xerophytic shrubs in which deodar, chilgoza, oak ash, maple, olive, celtis , parrotia, etc. are the ,ain trees. Such forests are found in the inner dry ranges of the Himalayas as where south-west monsoon is very feeble and the precipitation is below 100 cm, mostly snow. Such areas are in Ladakh, Lahul, Chamba, Kinnaur, Garhwal and Sikkim.

Montane sub tropical forests Sub Tropical broad leaved hill forest:-These forest are found in the eastern Himalayas to the east of 88’E longitude at altitude varying from 1000 to 2000m where the mean annual rainfall is 75 cm to 125 cm, average annual temperature is 18℃-21℃ and the average humidity is 80%. They form luxuirous forests of evergreen species, are fairly high(20-30 meters) and dense. Sub Tropical moist Pine forest:- These forests also occur at the same heights as the wet hill forests i.e1000 to 2000 meters above the sea level but in the western Himalayas between 73’E and 88’E longitudes. Some parts of Arunachal Pradesh, Manipur, Naga Hills and Khasi Hills of Meghalaya are also covered by such forests at similar altitudes. It provide valuable timber for furniture, boxes and buildings. Sub Tropical Dry evergreen forest:- Like the tropical moist evergreen, this occurs in a restricted area and is found in the Bhabar, the Shiwaliks and the Western Himalayas upto about 1000 meters above the sea level. Here the rainfall is 50-100 cm(15-25 cm in Dec-March). The summers are sufficiently hot and winters are cold enough for the occurrence of frequent frost. This is a low, practically scrub forest with a small evergreen stunted trees and shrubs, including thorny species, herbs and grasses. Olive, acacia modesta and Pistacia are the most predominant species. Considerable tracts are covered by dwarf creeping palm Nonnorpops..

Alpine forests Sub-Alpine Forests:-The sub-Alpine forests occur at the upper limit of tree forest adjoining alpine scrub and grasslands and comprise of dense growth of small crooked trees and large shrubs with coniferous overwood. It is a mixture of coniferous and broad leaved trees in which the coniferous trees attain a height of about 30 m while the broad leaved reach only 10m. Fir, kali, spruce, rhododendron, plum, yew, etc. are important species. Moist-Alpine Forests:- These have a low evergreen dense growth of rhododendron, birch, berberis and honeysuckle which occurs from 3000 meters and exends upto snowline. Dry-Alpine Forests:- This is the uppermost limit of scrub xerophytic, dwarf shrubs, over 3500 meters above sea level and found in dry zone. Juniper, honeysuckle, artemisia, potentilla, etc. are important species..

Let us now discuss about the CLIMATE OF INDIA.

Different Types of Climatic Regions. The climates of India are mainly divided into four different groups. The classification of these groups is based on the Koppen climate classification system. Tropical Wet (Humid): The tropical wet (humid) climate group in India is divided into two subparts - tropical monsoon climate or the tropical wet climate, and tropical wet and dry climate or savannah climate. The Western Ghats, the Malabar Coast, southern Assam, Lakshadweep and Andaman and the Nicobar Islands have the tropical monsoon climate. It experiences moderate to high temperature with seasonal but heavy rainfall. The months from May to November experience the most rainfall and the rain received during this period is sufficient for vegetation throughout the year. Tropical wet and dry climate or the savannah climate is most common in the country. It prevails mainly in the inland peninsular region of the country except for some portion of the Western Ghats. The summers are scorching and the rainy season extends from June to September. Tropical Dry: The tropical dry climate group is divided into three subdivisions (a) tropical semi-arid (steppe) climate, (b) sub-tropical arid (desert) climate and (c) sub-tropical semi-arid (steppe) climate. Karnataka, central Maharashtra, some parts of Tamil Nadu and Andhra Pradesh experience the tropical semi-arid (steppe) climate. Rainfall is very unreliable in this type of climate, and the hot and dry summers are experienced from March to May. With scanty and erratic rainfall and extreme summers, western Rajasthan witnesses the sub-tropical arid (desert) climate. The areas of the tropical desert that runs from the regions of Punjab and Haryana to Kathiawar witness the sub-tropical semi-arid (steppe) climate. The maximum temperature in summers goes up to 40°C, and the rains are unreliable and generally take place during summer monsoon season in this climate..

Sub-tropical Humid Climate: This climate is witnessed by most of the North and Northeast India. Summers are scorching, while in winters, the temperature can plunge to as low as 0°C. Rainfall mainly occurs in summers, but snowfall or occasional rain in winters is also witnessed in some areas. The hottest months are May, and June and frost also occur for few months in winters. Mountain Climate: The temperature falls by 0.6°C for every 100 m rise in altitude in the Himalayas and results in several different climates from tropical to tundra. The trans-Himalayan belt, which is the northern side of the western Himalayas, is cold, arid and windswept. There is less rain on the leeward side of the mountains whereas the well-exposed slopes receive heavy rainfall. The heaviest snowfall occurs between December to February..

Seasons of India. India generally witnesses four types of seasons. During these seasons, substantial variations in temperature take place in the country. The different types of seasons experienced in India are as follows: Winter: Generally, the months of January and February are considered as the start of the winter season in the country. However, in some parts of north-western India, the season begins from December. Generally, the average temperature during this season is about 10-15°C in northwest regions. In the southeast region of mainland India, the average temperature is about 20-25°C. The western Himalayas, the extreme north-eastern parts and Kerala and Tamil Nadu, experience rains during this season. Summer/Pre-monsoon/Thunderstorm/Hot Weather: The country experiences this season from March till June. In the interior peninsular regions, the mean daily temperature is recorded at 30-35°C. The maximum temperature in the daytime in Central India crosses 40°C in many areas. In some regions, the temperature is high during daytime while in the nights, low temperature is recorded. The coastal areas of the country have mild temperature during this season due to the influence of land and sea breezes. Thunderstorms with rains and hail influence the weather in the land areas of the country. These thunderstorms are seen in the north-eastern and eastern parts of Bihar, Assam and West Bengal. In the plains of northwest India, hot and dry winds, along with dust winds, are frequently experienced..

Rainy/South-west Monsoon: The months from July to September are the most significant. The monsoon torrents supply about 75% of the total rainfall of the country during this season. The exact period of the SW monsoon in a region depends upon the onset and withdrawal time of the season. For instance, it remains in west Rajasthan for about 75 days while it stays for 120 days in the south-western regions of the country. The SW monsoon reaches in two branches: the Arabian Sea and the Bay of Bengal branch. The Arabian Sea branch extends towards the low-pressure area over the Thar Desert and is about three times stronger than the Bay of Bengal branch. The northern hemispheric temperatures, El Nino, snow cover, sea surface temperature and many others are some of the local and global phenomena which influence the monsoons in the country. The SW starts to weaken by September 1 in Rajasthan and from September 15 in some north-western parts of the country. The monsoons in India are very important for the economy of the country as it affects agriculture which is the mainstay of a massive workforce of the nation. Autumn/Post Monsoon/Northeast Monsoon/Retreating SW Monsoon: This season prevails in the country from October to December. It is a transition season which is related to the establishment of the north-easterly wind regime over the subcontinent of the country. A large part of the country experiences cool, dry, and dense Central Asian air masses. Some parts of Tamil Nadu, Kerala, Karnataka and Andhra Pradesh receive about 35% of their total rainfall during this season. A decline in the mean temperature from 38°C in October to 28°C in November takes place during this season. The characteristic features of this season include a decrease in humidity level and clear skies in most parts of the central and northern India..

There are various Factors Affecting India’s Climate. Below mentioned are some of the reasons . Latitude. The Tropic of Cancer passes through the middle of India and extends from Mizoram in the east and Rann of Kutch in the west; and considerably affects the climate of the country. To the south of the Tropic of Cancer lies the southern part of the country which belongs to the tropical area and its north lies the northern half of India which belongs to the sub-tropical zone. Therefore, India experiences both sub-tropical and tropical climates. Altitude:-In the north, India is bounded by mountains with an average height of 6,000 meters and in the south, has a vast coastline with a maximum elevation of about 30 meters. The Himalayas act as a barrier against the cold winds from Central Asia. Therefore, due to the altitude of these mountains, the Indian subcontinent experiences milder winters than Central Asia. Monsoon Winds:-The 'monsoon winds' is the most dominating factor influencing the climate of India. It is often called the monsoon climate. A reversal in the monsoon winds can bring a change in the season of the country, for instance, the extreme summer season suddenly changing to the rainy or monsoon season. The entire country receives rainfall due to the south-west summer monsoons from the Bay of Bengal and the Arabian Sea. Western Disturbances and Tropical Cyclones:-Large parts of peninsular India get influenced by the tropical cyclones which originate in the Arabian Sea and the Bay of Bengal. Most of the cyclones originate in the Bay of Bengal and influence the climatic conditions at the time of the south-west monsoon season. The western disturbances originate over the Mediterranean Sea and influence the weather conditions in the Western Himalayan region

India due to its diverse nature go through a number of Climate Related Calamities. A few are mentioned below Landslides and Floods:- Floods are the most common natural disaster in India and are caused due to the inadequate capacity of the river banks to carry high flows which are brought down from the upper catchment because of the heavy rains. Almost the entire country is flood-prone, and the precipitation events like torrential rains and flash floods have become common in central India in the last few decades. But, the regions located in the Indo-Gangetic plains and northeast India are more prone to floods. Erratic, excess or untimely monsoon rains can kill thousands of people and also harm the agriculture of the country. Droughts:-Drought is a situation which arises due to the scarcity of water. In India, agriculture depends on the rains or the monsoon season as a source of water. But, the shortage or failure of water supply results in the below-average crop yields. Climatic factors such as high wind, high temperature and low humidity also add to the severity of drought in India. Andhra Pradesh, Rajasthan, Gujarat, Odisha, some parts of Maharashtra and Karnataka are some of the drought-prone areas in the country. India has witnessed many famines such as the Bengal famine of 1770, 1876-77, 1899 and 1943, which took lives of millions of people. Tropical Cyclones:-These are the most devastating natural disasters which result in a massive loss of life and property. In India, the lives of the coastal habitats are profoundly affected by the cyclones. The areas near the Bay of Bengal and the Indian Ocean are the most cyclone-prone regions of the country. Coastal areas of Odisha, West Bengal, Tamil Nadu and Andhra Pradesh are more exposed to cyclones. During the time of cyclone, heavy rains, winds with high speed and storm surge are also experienced which also affect the lives of the people as it becomes difficult for them to get relief and supplies during this phenomenon. A super cyclone, Cyclone 05B that struck Odisha on October 29, 1999, is considered to be the deadliest cyclone in the country in the past few decades. It was deemed to be equivalent to Category 5 hurricane.

Below given table depicts the Climatic Regions In India.

Characteristics of Rainfall in India. The Areas of very little rainfall whic is lower than 50 cm are Western Rajasthan , northern part of Kashmir, the Deccan Plateau and Punjab. The Areas of low precipitation of 50-100 cm are Eastern Rajasthan, Upper Ganga basin, Southern plains of Karnataka, Punjab, Tamil Nadu, and Andhra Pradesh. The Areas of comparatively heavy rainfall of 100-200 cm are Southern areas of Gujarat, north-eastern Peninsular region, east Tamil Nadu, eastern Maharashtra, Western Ghats, Orissa, Madhya Pradesh, and the central Gangetic basin. The Areas of heavy rainfall with more than 200 cm are The western seashores, the Western Ghats, Hills of Meghalaya, and the Sub-Himalayan range territories in North East. West Bengal, Assam, Western Coast, and southern part of east Himalayas..

At last i would like to say a quote by Antoine Lavoisier which is Vegetation is the basic instrument the creator uses to set all of nature in common..

I hope you enjoyed and learned something from the project. Best wishes and THANK YOU.