NATURAL VEGETATION
Q. No. 1. “Leaf litter decomposes faster than in any other biome and as a result the soil surface is often almost bare. Apart from trees, the vegetation is largely composed of plant forms that reach up into the canopy vicariously, by climbing the trees or growing as epiphytes, rooted on the upper branches of trees.” This is the most likely description of: (UPSC CSE Prelims, 2021)
(a) Coniferous forest
(b) Dry deciduous forest
(c) Mangrove forest
(d) Tropical rain forest
Answer: (d)
Explanation:
● Tropical rain forests develop under persistently high temperature, abundant moisture and very high biological activity. They have a very short dry season, tall trees, thick multi-layered canopy and abundant climbers and epiphytes.
● Warm and moist conditions encourage bacteria, fungi and other decomposers to break down litter rapidly. Nutrients released from decomposing organic matter are rapidly absorbed by the dense vegetation.
● Luxuriant vegetation does not necessarily imply exceptionally fertile soil. In many humid tropical regions, intense rainfall causes strong leaching, while much of the nutrient capital is held in the living biomass and rapidly cycling organic matter.
● Option (a), coniferous forest, is incorrect. Coniferous forests generally occur in cooler temperate or mountain environments. Needle litter tends to decompose more slowly because low temperatures and chemically resistant litter suppress decomposition.
● Option (b), dry deciduous forest, is incorrect. Dry deciduous forests experience a pronounced dry season and trees commonly shed leaves to reduce transpiration. Their canopy is less permanently closed.
● Option (c), mangrove forest, is incorrect. Mangroves are controlled primarily by tidal influence, saline or brackish water, waterlogged substrates and coastal geomorphology. Their diagnostic adaptations are quite different.
● Option (d), tropical rain forest, is correct. Lianas and epiphytes are particularly useful elimination clues. They exploit tall trees for structural support and better access to sunlight in the canopy. The supplied source specifically associates these features with tropical rain forests.
Hence, option (d) is correct.
Q. No. 2. Consider the following States: (UPSC CSE Prelims, 2015)
- Arunachal Pradesh
- Himachal Pradesh
- Mizoram
In which of the above States do Tropical Wet Evergreen Forests occur?
(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (c)
Explanation:
● Tropical wet evergreen forests require high temperature, very high rainfall, high atmospheric humidity and a short or insignificant dry season. In India, their principal concentrations are in the Western Ghats, North-East and Andaman–Nicobar Islands.
● Arunachal Pradesh contains very humid foothill and lower-elevation tracts, particularly in the eastern Himalayan–North-Eastern transition, capable of supporting tropical wet evergreen vegetation. Hence, statement 1 is correct.
● Himachal Pradesh belongs predominantly to the western Himalayan climatic regime. Its major natural forest formations are subtropical pine, Himalayan temperate, sub-alpine and alpine types rather than tropical wet evergreen rainforest. Hence, statement 2 is incorrect.
● Mizoram receives abundant monsoonal rainfall and forms part of the humid North-Eastern region where tropical evergreen and semi-evergreen forests occur. Hence, statement 3 is correct.
Hence, option (c) is correct.
Q. No. 3. In India, which type of forest among the following occupies the largest area? (UPSC CSE Prelims, 2010)
(a) Montane Wet Temperate Forest
(b) Sub-tropical Dry Evergreen Forest
(c) Tropical Moist Deciduous Forest
(d) Tropical Wet Evergreen Forest
Answer: (c)
Explanation:
● According to the ISFR 2021, Tropical Dry Deciduous Forests constituted about 39.30% of the listed forest-type area and were the largest group. Tropical Moist Deciduous Forests constituted about 18.47% and were second.
● Option (a), Montane Wet Temperate Forest, is incorrect. It is confined mainly to suitable higher-elevation humid mountain environments and therefore occupies a much smaller area.
● Option (b), Sub-tropical Dry Evergreen Forest, is incorrect. This is a relatively restricted formation, mainly associated with portions of the north-western Himalayan/sub-Himalayan region.
● Option (c), Tropical Moist Deciduous Forest, is correct among the options. Moist deciduous forests have a very extensive distribution in India, including belts around the Western Ghats, Shiwalik–Terai tract, eastern Madhya Pradesh–Chhattisgarh, Chota Nagpur Plateau, Odisha and parts of the North-East.
● Option (d), Tropical Wet Evergreen Forest, is incorrect. Its climatic requirements restrict it mainly to India's very humid belts.
Hence, option C is correct.
Q. No. 4. In India, in which one of the following types of forests is teak a dominant tree species? (UPSC CSE Prelims, 2015)
(a) Tropical moist deciduous forest
(b) Tropical rain forest
(c) Tropical thorn scrub forest
(d) Temperate forest with grasslands
Answer: (a)
Explanation:
● Tropical Moist Deciduous Forests occur in India under a seasonal monsoon climate, generally receiving about 100–200 cm of annual rainfall, with a distinct dry season.
● Teak (Tectona grandis) is one of the characteristic and economically important species of these forests. It is widely distributed across central and peninsular India. Other important trees include sal (Shorea robusta), shisham, mahua, amla, semul, kusum and sandalwood.
● Option (b) is incorrect: Tropical rain forests are associated with very high rainfall (generally above 200 cm) and remain largely evergreen.
● Option (c) is incorrect: Tropical thorn forests occur in low-rainfall, semi-arid regions and contain drought-resistant thorny species.
● Option (d) is incorrect: Temperate forests occur mainly in cooler mountainous regions and include species such as oak, pine, fir and spruce.
Hence, option (a) is correct.
Q. No. 5. Consider the following trees: (UPSC CSE Prelims, 2023)
- Jackfruit (Artocarpus heterophyllus)
- Mahua (Madhuca indica)
- Teak (Tectona grandis)
How many of the above are deciduous trees?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (b)
Explanation:
● Deciduous plants shed their leaves periodically, usually in response to a season of physiological stress such as dryness or cold. In tropical India, the major driver is commonly the dry season.
● Jackfruit is generally an evergreen tropical tree. Its leaves are not shed simultaneously as a characteristic seasonal adaptation comparable to teak or mahua. Hence, statement 1 is incorrect.
● Mahua is a deciduous tree of central and peninsular India. It is also economically and culturally important for food, flowers, seeds, oil and local livelihoods. Hence, statement 2 is correct.
● Teak is distinctly deciduous. During the dry season it sheds its leaves, reducing transpiration when soil moisture becomes limiting. Hence, statement 3 is correct.
Hence, option (b) is correct.
Q. No. 6. Open stunted forests with bushes and small trees having long roots and sharp thorns or spines are commonly found in: (UPSC CSE Prelims, 2002)
(a) Eastern Odisha
(b) North-Eastern Tamil Nadu
(c) Shiwaliks and Terai region
(d) Western Andhra Pradesh
Answer: (d)
Explanation:
● The description is diagnostic of tropical thorn and scrub vegetation, produced by prolonged moisture deficiency.
● Its major adaptations include:
- deep or extensive root systems to obtain scarce moisture;
- reduced leaf area or seasonal leaflessness to reduce transpiration;
- thorns and spines, which may both reduce exposed surface and protect against browsing;
- short, scattered growth because water availability cannot support a closed tall canopy.
● Tropical thorn forests are associated with rainfall generally below about 75 cm and with Rajasthan, south-western Punjab, western Haryana, Kutch–Saurashtra and rain-shadow/semi-arid portions of the Deccan, including Andhra Pradesh.
● Option (d), Western Andhra Pradesh, is correct. The drier interior/Rayalaseema-type environment provides the necessary semi-arid conditions.
Hence, option (d) is correct.
Q. No. 7. Which one of the following pairs is correctly matched? (UPSC CSE Prelims, 1997)
(a) Teak — Jammu and Kashmir
(b) Deodar — Madhya Pradesh
(c) Sandalwood — Kerala
(d) Sundari — West Bengal
Answer: (d)
Explanation:
● Option (a), Teak — Jammu and Kashmir, is incorrect. Teak is essentially a tropical deciduous tree of central and peninsular India, not a characteristic tree of the temperate western Himalayas.
● Option (b), Deodar — Madhya Pradesh, is incorrect. Deodar (Cedrus deodara) is a characteristic western Himalayan conifer, strongly associated with Jammu and Kashmir/Ladakh-region Himalaya, Himachal Pradesh and Uttarakhand rather than the central Indian plateau.
● Option (c), Sandalwood — Kerala, is not the intended correct association. Sandalwood occurs in parts of southern India, but its classical geographical association is especially with Karnataka and Tamil Nadu. Occurrence should not be confused with principal regional association.
● Option (d), Sundari — West Bengal, is correct. Sundari is characteristic of the Sundarbans mangrove ecosystem in the Ganga–Brahmaputra–Meghna deltaic region. India's Sundarbans lie in southern West Bengal.
● Mangroves occupy tidal creeks, estuaries, mudflats, salt marshes and deltaic environments where freshwater and seawater interact.
Hence, option (d) is correct.
Q. No. 8. Match List-I (Mangrove) with List-II (State): (UPSC CSE Prelims, 2002)
List-I
A. Achra–Ratnagiri
B. Coondapur
C. Pichavaram
D. Vembanad
List-II
- Karnataka
- Kerala
- Andhra Pradesh
- Maharashtra
- Tamil Nadu
(a) A-2, B-1, C-5, D-4
(b) A-4, B-5, C-3, D-2
(c) A-2, B-5, C-3, D-4
(d) A-4, B-1, C-5, D-2
Answer: (d)
Explanation:
● Achra–Ratnagiri → Maharashtra. Ratnagiri lies on the Konkan coast of Maharashtra, where sheltered creeks and estuarine environments support mangroves.
● Coondapur/Kundapura → Karnataka. It lies on Karnataka's west coast.
● Pichavaram → Tamil Nadu. Pichavaram is an important mangrove area on the Tamil Nadu coast.
● Vembanad → Kerala. Vembanad is the major backwater-lagoon system of Kerala.
● Mangroves are not restricted to major river deltas. They may occur around estuaries, creeks, lagoons, sheltered backwaters and tidal mudflats wherever appropriate salinity, tidal action and sediment conditions occur.
Final matching: A-4, B-1, C-5, D-2.
Hence, option (d) is correct.
Q. No. 9. If you travel through the Himalayas, you are likely to see which of the following plants naturally growing there? (UPSC CSE Prelims, 2014)
- Oak
- Rhododendron
- Sandalwood
(a) 1 and 2 only
(b) 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (a)
Explanation:
● Himalayan vegetation shows pronounced vertical zonation because temperature generally decreases with increasing altitude and moisture conditions also change.
● Oak is characteristic of several subtropical and temperate Himalayan belts, especially relatively moist mountain slopes. Hence, statement 1 is correct.
● Rhododendron is strongly associated with Himalayan montane, sub-alpine and alpine environments depending on species and elevation. Hence, statement 2 is correct.
● Sandalwood is essentially a warm-climate peninsular species and is not a characteristic naturally occurring Himalayan tree. Hence, statement 3 is incorrect.
● Other important Himalayan species include chir pine, deodar, silver fir, spruce, birch and juniper, but their elevations and moisture preferences differ.
Hence, option (a) is correct.
Q. No. 10. Which one of the following is not essentially a species of Himalayan vegetation? (UPSC CSE Prelims, 2008)
(a) Juniper
(b) Mahogany
(c) Silver fir
(d) Spruce
Answer: (b)
Explanation:
● Juniper is strongly associated with cold, high-altitude and comparatively dry Himalayan/sub-alpine environments.
● Silver fir is an important Himalayan conifer occurring in suitable cool and moist temperate to sub-alpine belts.
● Spruce is likewise characteristic of cool temperate Himalayan forests.
● Mahogany is not an indigenous characteristic species of Himalayan vegetation. It is native to tropical regions of the Americas and has been introduced/cultivated in other regions.
● Therefore Option (b) is not an essential Himalayan association.
- Hence, option (b) is correct.
Q. No. 11. Given below are an Assertion and a Reason:
Assertion (A): In the Himalayan mountains different types of vegetation are found.
Reason (R): In the Himalayas, there are variations in climate with change in altitude. (UPPCS Prelims, 2025)
(a) Both (A) and (R) are true, but (R) is not the correct explanation of (A)
(b) (A) is false, but (R) is true
(c) (A) is true, but (R) is false
(d) Both (A) and (R) are true and (R) is the correct explanation of (A)
Answer: (d)
Explanation:
● Assertion: Himalayan vegetation changes vertically from lower tropical/subtropical formations through temperate forests to sub-alpine shrubs and alpine vegetation. At still greater elevation, conditions become too severe for continuous woody vegetation. Therefore, Assertion (A) is true.
● Reason: Altitude modifies temperature strongly. It also alters precipitation form, snow persistence, evapotranspiration, soil development and length of the growing season. Slope orientation and exposure further modify sunlight, moisture and wind. Therefore, Reason (R) is true.
● The climatic change accompanying altitude is not merely associated with the vegetation change; it is a major causal explanation for it.
● A conceptual analogy is altitudinal zonation ≈ compressed latitudinal zonation. Travelling upward through a high mountain can reproduce some of the climatic changes experienced when travelling from low toward high latitudes.
Both (A) and (R) are true, and (R) correctly explains (A).
Hence, option (d) is correct.
Q. No. 12. Given below are an Assertion and a Reason: (UPPSC RO/ARO Prelims, 2023)
Assertion (A): The northern slopes of the Himalayas have a thicker vegetation cover compared with the southern slopes.
Reason (R): Southern slopes of the Himalayas receive more rainfall than the northern slopes.
Code:
(a) (A) is false but (R) is true
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A)
(c) Both (A) and (R) are true and (R) is the correct explanation of (A)
(d) (A) is true but (R) is false
Answer: (a)
Explanation:
● The southern Himalayan slopes face moisture-bearing monsoon winds arriving from the Indian plains. Orographic uplift enhances precipitation on these windward slopes.
● The northern/inner Himalayan and Trans-Himalayan regions lie increasingly in a rain-shadow environment, especially where the Greater Himalaya blocks monsoonal moisture.
● Because moisture is a fundamental vegetation control, the southern Himalayan slopes generally support more luxuriant vegetation than comparable dry northern/inner slopes. Therefore, Assertion (A) is false.
● The southern slopes generally receive more monsoonal rainfall than northern/inner Himalayan slopes because of their windward position relative to the South Asian monsoon circulation. Therefore, Reason (R) is true.
● Slope vegetation is also affected by aspect, local relief, altitude, soil, snow cover, disturbance and latitude.
Hence, option (a) is correct.
Q. No. 13. Match List-I with List-II and select the correct answer: (UPPCS Prelims, 2001)
List-I — Forest
A. Tropical moist deciduous
B. Tropical dry deciduous
C. Alpine
D. Tropical evergreen
List-II — Region
- Arunachal Pradesh
- Sahyadris
- Middle Ganga Plain
- Tarai
(a) A-4, B-3, C-1, D-2
(b) A-4, B-2, C-1, D-3
(c) A-1, B-3, C-2, D-4
(d) A-3, B-1, C-4, D-2
Answer: (a)
Explanation:
● Tropical moist deciduous → Tarai. The moisture-rich Himalayan foothill belt supports moist deciduous vegetation, including sal-dominated formations in appropriate areas.
● Tropical dry deciduous → Middle Ganga Plain. Drier portions of the Gangetic and adjoining interior belt represent suitable dry-deciduous conditions, although extensive agricultural clearance has greatly modified the original vegetation.
● Alpine → Arunachal Pradesh. Arunachal Pradesh extends from tropical foothills to very high Eastern Himalayan elevations and therefore includes alpine vegetation at high levels.
● Tropical evergreen → Sahyadris. The western/windward slopes of the Western Ghats receive very heavy orographic rainfall and form one of India's core evergreen forest regions.
● This question demonstrates that a single State or mountain system may contain several vegetation belts. Arunachal Pradesh, for example, should not be memorised as “only alpine”; it has enormous vertical climatic diversity.
Final matching: A-4, B-3, C-1, D-2.
Hence, option (a) is correct.
Q. No. 14. An example of a multipurpose tree used in social forestry is: (UPPCS Mains, 2002)
(a) Sheesham
(b) Dhak
(c) Eucalyptus
(d) Khejri
Answer: (d)
Explanation:
● Social forestry broadly involves raising trees on community lands, farms, roadsides and other non-traditional forest areas to provide fuel, fodder, small timber and ecological benefits while reducing pressure on natural forests.
● Khejri (Prosopis cineraria) is particularly valuable in arid and semi-arid north-western India because it tolerates severe drought, heat and low rainfall.
● Its multipurpose character includes fodder, fuelwood, small timber, shade and support to agro-pastoral livelihoods. The supplied material therefore identifies Khejri as an important social-forestry species.
Hence, option (d) is correct.
Q. No. 15. Among the following districts, which one had the larger area under dense deciduous forest cover? (65th BPSC Prelims, 2019)
(a) Paschim Champaran
(b) Gaya
(c) Kaimur
(d) Nawada
(e) None of the above/More than one of the above
Answer: (a)
Explanation:
● Paschim Champaran lies in north-western Bihar along the Nepal border and includes the Valmiki landscape adjoining the Himalayan foothill–Terai environment. This makes its physical geography substantially different from the drier plateau-edge districts of southern Bihar.
● Gaya and Nawada are located farther south in Bihar and are associated with the southern uplands/plateau margins rather than the extensive Himalayan foothill forest landscape of north-western Bihar.
● Kaimur possesses important forested plateau and escarpment areas in south-western Bihar.
Hence, option (a) is correct.
Q. No. 16. Which of the following are major controls of natural vegetation in India?
- Temperature
- Rainfall
- Soil
- Topography
(a) 1 and 2 only
(b) 1, 2 and 3 only
(c) 2, 3 and 4 only
(d) 1, 2, 3 and 4
Answer: (d)
Explanation:
● Climate is usually the dominant broad-scale control. Rainfall determines moisture availability, while temperature controls growing season, evapotranspiration and physiological limits. Hence, statement 1 is correct.
● Rainfall amount, seasonality and reliability are crucial in differentiating evergreen, deciduous, thorn and desert vegetation. Hence, statement 2 is correct.
● Soil or edaphic factors become especially conspicuous where salinity, drainage, waterlogging or substrate properties dominate. Mangrove and swamp vegetation are important examples. Hence, statement 3 is correct.
● Topography alters elevation, slope, aspect, drainage and exposure and therefore produces strong vegetation differences, especially in mountains. Hence, statement 4 is correct.
Hence, option (d) is correct.
Q. No. 17. Tropical semi-evergreen forests are best described as:
(a) A transition between tropical wet evergreen and tropical deciduous forests
(b) A transition between alpine vegetation and tundra
(c) A coastal saline forest dominated by pneumatophores
(d) A desert scrub formation dominated by xerophytes
Answer: (a)
Explanation:
● Tropical semi-evergreen forests occupy an ecological transition where moisture is high but the dry season is more pronounced than in true wet-evergreen rainforest.
● Consequently, evergreen and deciduous components can coexist and the canopy is generally less continuously luxuriant than true tropical wet evergreen forest.
● They are transitional forests between tropical wet evergreen and tropical deciduous formations and are associated with the western coast, Assam, lower Eastern Himalayan slopes, Odisha and Andamans.
Hence, option (a) is correct.
Q. No. 18. Tropical Dry Evergreen Forests of India are particularly associated with:
(a) The Coromandel/Tamil Nadu coast receiving substantial northeast monsoon rainfall
(b) The permanently humid western slopes of the Western Ghats
(c) The uppermost alpine belt of the Himalayas
(d) The cold desert of Ladakh
Answer: (a)
Explanation:
● Tropical dry evergreen forest is an important exception to the simplistic rule that evergreen vegetation always requires extremely heavy annual rainfall.
● It occurs particularly along parts of the Tamil Nadu/Coromandel coast, where rainfall seasonality is strongly influenced by the northeast or retreating monsoon.
● Tropical dry evergreen forest lies along the Tamil Nadu coast and have rainfall of roughly 100 cm, much of it from the northeast monsoon.
● These forests are relatively short-statured compared with wet evergreen rain forests.
Hence, option (a) is correct.
Q. No. 19. Which combination of adaptations is most characteristic of mangrove vegetation?
(a) Needle leaves and conical crowns adapted to snowfall
(b) Deep taproots only, without adaptation to waterlogging
(c) Salt tolerance, specialised aerial roots in many species and reproduction adapted to tidal environments
(d) Complete absence of root modifications
Answer: (c)
Explanation:
● Mangroves inhabit highly stressful intertidal environments characterised by salinity, waterlogging, anaerobic mud, periodic tidal inundation and unstable sediment.
● Many species therefore possess specialised roots that facilitate gaseous exchange in oxygen-poor substrates. Pneumatophore-type aerial roots are a well-known example.
● Mangrove plants also possess mechanisms for tolerating, excluding or excreting salt depending on species. Several characteristic mangroves show vivipary, in which the embryo begins development while still attached to the parent plant, improving establishment in tidal mud.
● They are located in mangroves in deltas, estuaries, creeks, backwaters, salt marshes and mudflats.
Hence, option (c) is correct.
Q. No. 20. Which one of the following represents the most appropriate broad vertical sequence of natural vegetation while ascending the Himalayas from low elevation?
(a) Alpine → Tropical → Temperate → Subtropical
(b) Tropical/Subtropical → Temperate → Sub-alpine → Alpine
(c) Temperate → Mangrove → Tropical thorn → Alpine
(d) Tropical evergreen → Mangrove → Desert → Tundra
Answer: (b)
Explanation:
● Increasing altitude normally causes decreasing temperature and progressively shorter growing seasons.
● Lower Himalayan elevations can sustain tropical/subtropical formations according to rainfall and locality.
● At middle elevations, temperate broad-leaved and coniferous forests become important.
● These give way upward to sub-alpine woodland/scrub and then alpine grasslands and dwarf vegetation near the climatic tree line.
Hence, option (b) is correct.