TERRESTRIAL ECOSYSTEM

A terrestrial ecosystem is a land-based community of organisms and the interactions of biotic and abiotic components in a given area.

The interrelationships between organisms and the environment on the land constitute a terrestrial ecosystem. Due to variations in the topographic features of valleys, mountains and slopes, certain differences occur. These differences are reflected in both the material and biotic diversities. Altitudinal and latitudinal variations cause shifts and differences in climatic patterns. Due to varied climate, the plant and animal life existing in different historical areas vary which result in the differentiation of ecosystem as segments within the large biosphere. The most important limiting factors of the terrestrial ecosystem are moisture and temperature.

1. Tundra

Tundra means a “barren land“, as they are found where the environmental conditions are very severe. There are two types of tundra- Arctic and Alpine.

Distribution

Arctic tundra extends as a continuous belt below the polar ice cap and above the tree line in the northern hemisphere. It occupies the northern fringe of Canada, Alaska, European Russia, Siberia and the island group of the Arctic Ocean. On the South Pole, the tundra is very small since most of it is covered by ocean.

Alpine tundra occurs at high mountains above the arctic mountains and is found at all latitudes. Therefore alpine tundra shows day and night temperature variations.

Flora & Fauna

• Typical vegetation of arctic tundra is cotton grass, sedges, dwarf heath, willows, birches and lichens.
• Animals of tundra are reindeer, musk oxs, arctic hares, caribous, and squirrels.
• Most of them have long life e.g. arctic willow has a lifespan of 150-300 years.
• They are protected from chillness by the presence of thick cuticles and epidermal hair.
• Mammals of the tundra region have large body sizes, small tails and small ears to avoid the loss of heat from the surface.
• The body is covered with fur for insulation. Insects have short life cycles which are completed during favorable periods of the year.

2. Forest Ecosystem

The forest ecosystem includes a complex assemblage of different kinds of biotic communities. Optimum conditions like temperature and ground moisture are responsible for the establishment of forest communities.

The nature of soil, climate and local topography determine the distribution of trees and their abundance in the forest vegetation. Forests may be evergreen or deciduous. They are distinguished based on leaf into broad-leafed or needle-leafed coniferous forests in case of temperate areas.

The forest ecosystem has been classified into three major categories-

1. Coniferous forest
2. Temperate forest
3. Tropical forest

All these forest biomes are generally arranged on a gradient from north to South latitude or from high to lower altitudes.

• Cold regions with high rainfall, strong seasonal climates with long winters and short summers or characterized by Boreal coniferous forest.
• This is characterized by evergreen plant species like spruce, fir pine trees etc., by animals like lynx, wolf, bear, red fox, porcupine, squirrel and amphibians like hyla and Rana.
• Boreal forest soils are characterized by thin podsols and are poor. Because the weathering of rocks proceeds slowly in cold environments the litter derived from conifer needles (leaf) is decomposed very slowly and is not rich in nutrients.
• These soils are acidic and are mineral deficient. This is due to the movement of large amounts of water through the soil, without a significant counter upward movement of evaporation, essential soluble nutrients like calcium, nitrogen and potassium which are leached sometimes beyond the reach of roots. This process leaves no alkaline-oriented cations to encounter the organic acids of the accumulating litter.
• The productivity and community stability of a boreal forest are lower than those of any other forest ecosystem.

Temperate deciduous forest

• The temperate forests are characterized by a moderate climate and broad-leafed deciduous trees, which shed their leaves in fall and bare over winter and grow new foliage in the spring.
• The precipitation is fairly uniform throughout.
• Soils of temperate forests are podzolic and fairly deep.

Temperate Evergreen forest

• Parts of the world that have the Mediterranean type of climate are characterized by warm, dry summers and cool, moist winters.
• These are commonly inhabited by low broad-leaved Evergreen trees.
• Fire is an important hazardous factor in this ecosystem and the adaptation of the plants enables them to regenerate quickly after being burnt.

Temperate rainforests

• The temperate rainforests exhibit a marked seasonality in temperature and rainfall.
• Rainfall is high and fog may be very high. It is an important source of water than rainfall.
• The biotic diversity of temperate rainforest is high as compared to other temperate forest. However, the diversity of plants and animals is much lower as compared to the tropical rainforest.

Tropical rainforests

• Tropical rainforests occur near the equator. They are the most diverse and rich communities of the earth.
• Both temperature and humidity remain high and more or less uniform.
• The annual rainfall exceeds 200 centimetres and is generally distributed throughout the year.
• The flora is highly diversified.
• The extremely dense vegetation of the tropical rainforest remains vertically satisfied with all trees often covered with vines, creepers epiphytic orchids, lianas etc.
• Lowest layer is an understory of trees shrubs herbs like ferns and palms.
• Soil of tropical rainforests are red latosols and they are very thick.
• The high rate of leaching makes these soils virtually useless for agricultural purposes, but when left undisturbed, the rapid cycling of nutrients within the litter layer, formed due to decomposition can compensate for the natural poverty of the soil.
• Undergrowth is restricted in many areas by the lack of sunlight at ground level.

Tropical seasonal forests

• Tropical seasonal forests also known as monsoon forests occur in regions where total annual rainfall is very high but segregated into pronounced wet and dry periods.
• This kind of forest is found in Southeast Asia, Central and South America, northern Australia, western Africa and the Tropical islands of the Pacific and India.

Subtropical rainforests

• Broad-leafed evergreen subtropical rainforests are found in regions of fairly high rainfall but with fewer temperature differences between winter and summer.
• Epiphytes are common.
• Animal life in subtropical forests is very similar to that of tropical rainforests.

3. Indian Forest Types

India has a diverse range of forests 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 forest. Forests vary according to their nature and composition, the type of climate in which they thrive, and their relationship with the surrounding environment.

Forest types in India are classified by Champion and Seth into sixteen types.

1. Tropical Wet Evergreen Forests: Wet evergreen forests are found along the Western Ghats, the Nicobar and Andaman Islands and all along the northeastern region. It is characterized by tall, straight green trees. The more common trees are the jackfruit, betel nut palm, jamun, mango, and hollock. The trees in this forest form a tiered pattern- shrubs cover the layer closer to the ground, followed by the short structured trees and then the tall trees. Beautiful ferns of various colours and different varieties of orchids grow on the trunks of the trees.
2. Tropical Semi-evergreen forests: Semi-evergreen forests are found in the western ghats, Andaman and Nicobar Islands and the eastern Himalayas. 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.
3. Tropical Moist deciduous forests: Moist deciduous forests are found throughout India except in the western and north-western regions. The trees are tall, and have broad trunks, 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.
4. Littoral and swamp: Littoral and swamp forests are found along the Andaman and Nicobar Islands and the delta area of the Ganga and the Brahmaputra. They have roots that consist of soft tissues so that the plant can breathe in water.
5. Tropical Dry Deciduous Forest: Dry deciduous forests are found throughout the northern part of the country except in the northeast. It is also found in Madhya Pradesh, Gujarat, Andhra Pradesh, Karnataka and Tamil Nadu. The canopy of the trees does not normally exceed 25 meters. The common trees are the sal, a variety of Acacia, and bamboo.
6. Tropical Thorn forests: This type is found in areas with black soil like north, west, central and south India. The trees do not grow beyond 10 meters. Spurge, caper and cactus are typical of this region.
7. Tropical Dry evergreen forest: Dry evergreens are found along Tamil Nadu, Andhra Pradesh and Karnataka coasts. It is mainly hard-leaved evergreen trees with fragrant flowers, along with a few deciduous trees.
8. Sub-tropical Broad-leaved forests: Broad-leaved forests are found in the Eastern Himalayas and the Western Ghats, along the Silent Valley. There is a marked difference in the form of vegetation in the two areas. In the Silent Valley, poonspar, cinnamon, rhododendron and fragrant grass are predominant. In the Eastern Himalayas, the flora has been badly affected by the shifting cultivation and forest fires. These wet forests consist mainly of evergreen trees with a sprinkling of deciduous. There are oak, alder, chestnut, birch and cherry trees. There are a large variety of orchids, bamboo and creepers.
9. Sub-tropical Pine forests: Pine forests 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 as well as sal, amla and laburnum are found in the lower regions.
10. Sub-tropical Dry evergreen forests: Dry evergreen forests 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. These forests are found in the Shivalik Hills and foothills of the Himalayas up to a height of 1000 meters.
11. Montane Wet temperate forests: In the North, Montane wet temperate forests are found in the region to the east of Nepal into Arunachal Pradesh, receiving a minimum rainfall of 2000 mm. There are 3 layers of forest in the North:  the higher layer is mainly coniferous, the middle layer has deciduous trees like oak and the lowest layer is covered by rhododendrons and champa. 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. Rhododendrons and a variety of ground flora are found here.
12. Himalayan Moist temperate Forest: This type of forest spreads 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-leaved trees, ferns and bamboo. Coniferous trees are also found here, some of the varieties being different from the ones found in the South.
13. Himalayan Dry temperate Forest: This type is found in Lahul, Kinnaur, Sikkim and other parts of the Himalayas. There are predominantly coniferous trees, along with broad-leaved trees like oak, maple and ash. At higher elevations, fir, juniper, and deodar are found.
14. Subalpine Forest: Subalpine forests extend from Kashmir to Arunachal Pradesh between 2900 – 3500 meters. In the Western Himalayas, the vegetation consists mainly of juniper, rhododendron, willow and black currant. In the Eastern parts, red fir, black juniper, birch and larch are the common trees. Due to heavy rainfall 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.
15. Moist Alpine Scrub: Moist Alpines 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.
16. Dry Alpine Scrub: Dry Alpines 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 Forest

From the air we breathe and the food we eat to the paper and wood we use; we depend on forests directly or indirectly. Without forests, most of the areas would have been deserts.

• Forests keep up the natural balance.
• They purify the air.
• Forests provide microclimate.
• Forests indirectly play a role in precipitation.
• Forests prevent floods and soil erosion.
• They provide medicinal properties.
• Forests provide us with fuel and timber.
• Forests provide raw materials for industries.

4. Deforestation

Indiscriminate felling of trees as a result of urbanization, industrialization, mining operations and use of wood for domestic and other purposes, have caused heavy depletion of forests.

Causes

Shifting Cultivation

• In this practice a patch of land is cleared, vegetation is burned and the ash is mixed with the soil thus adding nutrients to the soil.
• This patch of land is used for two to three years, and the yield is modest.
• Then this area is abandoned and is left to recover its fertility and the same practice is repeated elsewhere on a fresh piece of land.
• All that is required for this method of cultivation is a set of simple tools, not a high level of mechanization.

Development Project

• The human population have increased considerably, according to their requirements.
• Development projects like hydroelectric projects, large dams and reservoirs, and laying down of railway lines and roads are not only extremely beneficial but they are also linked with several environmental problems.
• Many of these projects require immense deforestation.

Fuel Requirements

The increasing demand for firewood with an ever-growing population increases greater pressure on the forests, which results in increased intensity of deforestation.

Raw Material Requirements

• Wood is used as a raw material by various industries for making paper, plywood, furniture, matchsticks, boxes, crates, packing cases etc.,
• Industries also obtain their raw materials from plants like drugs, scents and perfumes, resins, gums, waxes, turpentine, latex and rubber, tannins, alkaloids, bees wax.
• This exerted tremendous pressure on the forest ecosystem and their unrestricted exploitation of various other raw materials is the main cause of the degradation of the forest ecosystem.

Other causes- Deforestation also result from overgrazing, agriculture, mining, urbanization, flood, forest fire, pests, diseases, and defence and communication activities.

Effects of Deforestation

• Closed forests are diminished due to deforestation leading to an increase in degraded forests.
• Forests recycle moisture from soil into their immediate atmosphere by transpiration where it again precipitates as rain.
• Deforestation results in an immediate lowering of groundwater level and long-term reduction of precipitation.
• Due to deforestation, this natural reuse cycle is broken and water is lost through rapid runoff.
• Much of the mining activity in India is being carried out in forest regions. The obvious result is deforestation and soil erosion.
• Underground mining has also significantly denuded forests, as timber is used for supporting the roofs of mine galleries.
• A large number of abandoned mines are lying in bad shape and are under extensive gully erosion leading to degradation of the habitat.
• Deforestation affects the biota and neighbouring ecosystems, soil erosion, land degradation, alteration of groundwater channels, pollution and scarcity.

5. Grassland ecosystem

• The grasslands are found where rainfall is about 25-75 cm per year, not enough to support a forest, but more than that of a true desert.
• Typical grasslands are vegetation formations that are generally found in temperate climates. In India, they are found mainly in the high Himalayas. The rest of India’s grasslands are mainly composed of steppes and savannas.
• The major difference between steppes and savannas is that all the forage in the steppe is provided only during the brief wet season whereas in the savannas forage is largely from grasses that not only grow during the wet season but also from the smaller amount of regrowth in the dry season.
• Steppe formations occupy large areas of sandy and saline soil; in western Rajasthan, where the climate is semi-arid, the average rainfall is less than 200 mm a year with a dry season of 10-11 months, and a large variation in rainfall.
• The soil is always exposed, sometimes rocky but more often sandy with fixed or mobile dunes. Forage is available only during the brief wet season. The grass layer is sparse and consists mainly of annual grass species.
• In the central and eastern parts of Rajasthan, where the rainfall is about 500mm per year and the dry season is 6-8 months, dry savanna grazing ecosystems have developed. The light shade cast by the sparse population of trees like khetri favours the growth of the grasses.

Types of grasslands

Based on climatic conditions there are 6 types of grasslands found in the different regions of the Indian subcontinent.

1. Semi-arid zone- It covers the northern portion of Gujarat, Rajasthan(except Aravallis), western Uttar Pradesh, Delhi and Punjab. The topography is broken up by hill spurs and sand dunes.
2. Dry sub-humid zone- It covers the whole of peninsular India(except Nilgiri).
3. Moist sub-humid zone- It covers the Ganga alluvial plain in Northern India. The topography is level, low lying and ill-drained.
4. Humid montane regions- This extends to the humid montane regions and moist sub-humid areas of Assam, Manipur, West Bengal, Uttar Pradesh, Punjab, Himachal Pradesh, Jammu and Kashmir.

Economic Importance of Grasslands

• India teems with animals of all shapes and sizes from buffaloes to sheep and there are millions of them.
• The Livestock wealth plays a crucial role in Indian life. It is a major source of fuel, drought power, nutrition and raw materials for village industries.
• Only 13 million hectares in the country are classified as permanent grazing lands. On top of it, they exist in a highly degraded state.
• Grassland biomes are important to maintain the population of many domesticated and wild herbivores.
• Indian Grasslands and Fodder Research Institute, Jhansi and Central Arid Zone Research Institute, Jodhpurs.

Impact of grazing

• Due to heavy grazing pressure, the quality of grasslands deteriorates rapidly, the mulch cover of the soil reduces, microclimate becomes more dry and is readily invaded by xerophytic plants and borrowing animals.
• Due to the absence of humus cover, the mineral soil surface is heavily trampled, when wet it produces puddling of the surface layer.
• In turn it reduces the infiltration of water into the soil and accelerates runoff,  resulting in soft erosion.
• These changes contribute to the reduction of energy flow, and that description of the stratification and periodicity of the primary producers. It results in a breakdown of the biogeochemical cycles of water, carbon and nitrogen.
• Water and wind erosion completely deteriorates dry grassland climate.

  Role of fire

• Fire plays an important role in the management of grasslands.
• Under moist conditions fire favors grass over trees, whereas in dry conditions fire is often necessary to maintain grasslands against the invasion of desert shrubs.
• Burning increases the forage yields.

6.  Desert ecosystem

• Deserts have been found in regions with less than 25 centimetres of annual rainfall, or sometimes in hot regions where there is more rainfall, but unevenly distributed in the annual cycle.
• The climate of these biomes is modified by altitude and latitude. At high altitudes and greater distances from the equator, the deserts are cold and hot near the equator and tropics.
•  The perennial plants like creosote bush and cactus are scattered throughout the desert biomes.
• In shallow depressed areas with salt deposits geese-wood, seep-wood and saltgrass are common.
• As water is the dominant limiting factor, the productivity of a given desert is almost directly dependent on the rainfall, where soils are suitable, irrigation can convert deserts into productive agricultural land.
• As a large volume of water passes through the irrigation system, salts may be left behind that will gradually accumulate over the years until they become limiting.

 Adaptations-Desert plants are under hot and dry conditions.

• Plants are mostly shrubs.
•  Leaves are absent or reduced in size.
• Leaves and stems are succulent and water storing.
• In some plants even the stem contains chlorophyll for photosynthesis.
• Root system is well developed and spread over a large area.

The annuals wherever present germinate, bloom and reproduce only during the short rainy season and not in summer, or winter. This is an adaptation to desert conditions.

• They are fast runners.
• They are nocturnal in their habitat to avoid the sun’s heat during the daytime.
• They conserve water by excreting concentrated urine.
• Animals and birds usually have long legs to keep their body away from the hot ground.
• Lizards are mostly insectivorous and can live without drinking water for several days.
• Herbivorous animals get sufficient water from the seeds they eat.
• Camel is known as the ship of the desert as it can travel long distances without drinking water for several days.
• Mammals as a group are poorly adapted to deserts but some species have become secondarily adapted. A few species of nocturnal rodents can live in the desert without drinking water.

 Indian desert- Thar desert(hot)

• The climate of this region is characterized by excessive drought, the rainfall being scanty and irregular.
• The winter rains of northern India rarely penetrate the region.
• November to March is characterized by extreme variations of temperature and the temperature is frequently below freezing point at night.
• During April to June the heat is intense, and frequent scorching winds prevail with great desiccation.
• The relative humidity of the atmosphere is always low.
• The climate is hostile to all vegetation, only plants and animals possessing special adaptations being able to establish themselves.

Flora-  The proper desert plants may be divided into two main groups.

1. Depending directly on rain
2. Those depending on the presence of subterranean water.

The first group consists of two types

• Depending directly upon the rain are two types- the ephemerals and the rain perennials.
• The ephemerals are delicate annuals, apparently free from any xerophilous adaptations, having slender stems and root systems, often with large flowers. They appear almost immediately after rain, develop flowers and fruits in an incredibly short time, and die as soon as the surface layer of the soil dries up.
• The rain perennials are visible above the ground only during the rainy season but have a perennial underground stem.

The second group -depending on the presence of sub-terrance and water

• By far the largest number of indigenous plants are capable of absorbing water from deep below the surface of the ground using a well-developed root system, the main part of which generally consists of a slender, woody taproot of extraordinary length.
• Generally, various other xerophilous adaptations are resorted to such as reduced leaves, thick hairy growth, succulence, coatings of wax, thick cuticle, protected stomata etc., all having for their object of reduction of transpiration.

Fauna

• It is home to some of India’s most magnificent grasslands and a sanctuary for the Great Indian Bustard.
• Among the mammal, the blackbuck, wild ass, chinkara, caracal, sandgrouse and desert fox inhabit the open plains, grasslands and saline depressions.
• The nesting ground of Flamingoes and the only known population of Asiatic wild Ass lies in the remote part of Great Rann, Gujarat.
• It is the migration flyway used by cranes and flamingoes.

Cold Desert/Temperate Desert

Cold deserts of India include areas of Ladakh, Leh and Kargil of Kashmir Spiti Valley of Himachal Pradesh and some parts of northern Uttaranchal and Sikkim. These arid areas are not affected by the Indian monsoons because they lie in the rain shadow of the Himalayan mountain systems.

Characterized by extreme cold weather and denuded terrain they are not suitable for plant growth. Isolated, scattered and overgrazed herbaceous shrubs are found. The grazing period is less than 3-4 months.

Characters

• Severe arid conditions atmosphere.
• Temperature less than 0⁰ C for most of the period, drops to -50⁰ C during winter.
• Insignificant monsoon-mean annual rainfall less than 400mm.
• Heavy snowfall occurs between November and March.
• Sandy- sandy loam soil type is present.
• PH of the soil is neutral to slightly alkaline.
• Soil nutrient-  poor organic matter content.
• Soil has low water retention capacity.
• Wind erosion is more common.
• Narrow growing Period, Mostly during the summer.
• Due to aforesaid extreme cold conditions, the growth of vegetation is slow and of stunted nature.

Bio-diversity

• Cold desert is the home of highly adaptive, rare endangered fauna, like Asiatic ibex,  Tibetan argali, Ladakh urial, Bharal,  Tibetan antelope(chiru), Tibetan gazelle, wild yak, snow leopard, brown bear, Tibetan wolf, wild dog and Tibetan wild ass(kiang-a close relative of the Indian wild ass), woolly hare, black Necked Crane, etc.
• Cold desert comprises Alpine Mesophytes and desert vegetation.
• Dry temperature zone- Betula, Salix, Juniperus.
• Alpine zone- Junipers, Birch, Rhododendron With grasses.
• Perpetual snow zone- no vegetation due to permanently frozen soil.
• Oak, pine, deodar, birch and rhododendron are important trees.

 7. Desertification

 It is the destruction of the biological potential of the land which can ultimately lead to desertlike conditions. In arid and semi-arid regions, the restoration of the fragile ecosystem is very slow, and issues like deforestation, and mining enhance desertification. Desertification is a main problem faced by desert adjoining areas, which stretches across parts of Rajasthan, Gujarat, Punjab and Haryana. The cause of this process is not climatic changes, or droughts but human actions.

 Causes

• Population pressure
•  Increase in cattle population, overgrazing
• Increased agriculture
• Development activities
• Deforestation

 Status of Indian desertification

 As per the Desertification and Land Degradation Atlas of India, 2007, the percentage of the country under dry lands is 69.6%. The total area undergoing the process of land degradation in India is 105.48 million hectares, which constitutes 32.07% of India’s total land area.

81.45 million hectares of area of the country are under desertification (land degradation within dry lands.)

Control measures

India is a signatory to the United Nations Convention to Combat Desertification (UNCCD). The National Action Program for combating desertification was prepared in 2001 to take appropriate action in addressing the problems of desertification.

Some of the major programs currently implemented that address issues related to land degradation and desertification are-

• Integrated Watershed Management Program
• National Afforestation Program
• National Mission for Green India
• The Mahatma Gandhi National Rural Employment Guarantee Scheme.
• Soil Conservation in the Catchment of River Valley Project and Flood Prone River.
• National Watershed Development Project for Rain-fed Areas.
• Desert Development Program
• Fodder and Feed Development Scheme- component of Grassland Development including Grass Reserves, Command Area Development Water Management program etc.

8. Afforestation

• The desert regions of Rajasthan, Gujarat, Haryana, Punjab and Trans-Himalayan regions are scarce of vegetation.
• People require firewood, timber, and fodder for their domestic consumption and livestock.
• The presence of vegetation prevents soil erosion and modifies the hostile climate.
• Thus desert Afforestation is inevitable to modify the climate, and desertification and to meet the demands of people living in that region.

Indian State of Forest Report, 2017

• The State of Forest Report has been published by the Forest Survey of India(FSI) on a biennial basis since 1987.
• The India State of Forest Report 2017 is the 15^th report in the series. It is based on the interpretation of LISS III sensor data of the indigenous Resource-sat-II satellite. The satellite data interpretation is followed by extensive and rigorous ground truthing.
• The total forest and tree cover is 24.39% of the total geographical area. Forest and tree Cover of the country has increased by 8,021 sq km(1%) as compared to the assessment of 2015. The very dense forest(VDF) has increased by 1.36% as compared to the last assessment. VDF absorbs the maximum carbon dioxide from the atmosphere.
• Madhya Pradesh has the largest forest cover in the country, followed by Arunachal Pradesh and Chhattisgarh.
• Mizoram, with 88.93% of forest cover has the highest forest cover in percentage terms, followed by Lakshadweep with 84.56%. The ISFR 2015 states that 15 states/Union Territories have more than 33% of the geographical area under forest cover.
• Out of these, 7 States/Union Territories-Mizoram, Lakshadweep, Andaman and Nicobar Islands, Arunachal Pradesh, Nagaland, Meghalaya and Manipur have more than 75% forest cover, while 8 states- Tripura, Goa, Sikkim, Kerala, Uttarakhand, Dadra Nagar Haveli, Chhattisgarh and Assam have forest cover is between 33% - 75%.
• India is ranked 10^th in the world in forest cover, with 24.39% of land area under forest and tree cover.
• As per the FAO report, India is placed 8^th in the list of Top Ten nations reporting the greatest annual net gain in the forest area.

9. Interesting  Facts

• Spider silk is possibly the strongest material in the world. It is believed that if the same weight of a spider web as a piece of steel, the web would be much stronger than the steel. As hard as scientists try, they cannot match or copy the silk.
• According to the Global Forest Resource Assessment Report(Food & Agricultural Organisation-FAO-2005), India ranks among the top ten countries in terms of forest area. India has 1.8% of the global forest area with per capita forests of 0.08 ha.
• Polar Bears are very well adapted to swimming, with a water-repellent coat and partially webbed feet.
• Sri Venkateshwara Zoological Park, Tirupathi, is the largest zoo in the country.
• The elephant’s trunk combines both the nose and upper lip and transforms them into a single powerful organ that can touch, grasp and smell. It is strong enough to uproot a tree, sensitive enough to pick up a pea-sized fruit from the ground, and long enough to reach foliage high in the trees. The trunk is also used to drink by sucking up water and squirting it into the mouth.
• Reptiles are cold-blooded animals that raise their body temperature by lying in the sun or lowering it by crawling into the shade. Their body temperature changes to the temperature of their surroundings.
• Feathers of birds perform many jobs like keeping them warm, flight, and tail feathers for steering. The colour of the feathers can be used to hide the bird or to help the bird to find a mate.