CDS (II) 2022 General Knowledge · Question 3 of 120

Correct — B, Desert, Tropical thorny, Moist deciduous, Mangrove. Trace the road. Bikaner sits in the Thar, where rainfall is under about 25 cm and the cover is desert scrub — cactus, thorny bushes and stunted trees. Moving east and southeast through eastern Rajasthan and into Madhya Pradesh, rainfall rises to roughly 50-75 cm and the cover becomes tropical thorn forest, the belt NCERT places across Rajasthan, Gujarat, Madhya Pradesh, Haryana and Punjab. Across Chhattisgarh and interior Odisha rainfall crosses 100 cm and the sal and teak country of the tropical moist deciduous forest takes over — the largest forest type in India. The last stretch to Konark reaches the Odisha coast, where creeks and the Mahanadi delta carry mangrove. The sequence therefore runs dry to wet, ending at tidal salt water, which is the order given in option B.

• (a)Tropical thorny, Desert, Moist deciduous, Mangrove — Swaps the first two. You cannot pass through thorn forest before reaching the desert when the desert is where you start — Bikaner lies inside the arid zone, not on its wetter margin.
• (c)Moist deciduous, Tropical thorny, Mangrove, Desert — Runs the rainfall gradient backwards and finishes in the desert, which would put the Thar on the Bay of Bengal. It also drops mangrove into the middle of the journey, far from any coast.
• (d)Desert, Tropical thorny, Mangrove, Moist deciduous — Starts correctly, then inverts the last two. Mangrove is tidal and can only be the final belt before Konark; the moist deciduous forests of Chhattisgarh and inland Odisha come before it, not after.

India's natural vegetation follows rainfall more closely than it follows latitude. Champion and Seth's classes, which NCERT summarises, run from tropical evergreen forest in the wettest belts, through moist and dry deciduous, to tropical thorn forest in semi-arid country and desert scrub in the arid west, with montane forests on altitude and littoral and swamp forests — mangrove among them — on tidal coasts. A transect question simply asks you to read that gradient along a line on the map.

The way to attack this is to fix the two endpoints and let the middle sort itself. Bikaner is Thar; Konark is the Odisha coast a few kilometres from the sea. That already forces desert first and mangrove last, and only one option does both. If you must justify the middle, remember that thorn forest occupies the semi-arid transition and moist deciduous the wetter east — so the order is desert, thorn, moist deciduous, mangrove. The same test rewards knowing that tropical deciduous forest, taken as a whole, covers more of India than any other type.

• NCERT places tropical thorn forests in regions receiving less than 50 cm of rainfall, across Rajasthan, Gujarat, Madhya Pradesh, Chhattisgarh, Uttar Pradesh and Haryana.
• The desert and semi-desert of Rajasthan are described as country of cacti, a wide variety of bushes and thorny vegetation.
• Moist deciduous forests are the sal and teak belt of the wetter eastern half — Chhattisgarh, Jharkhand, Odisha and the eastern slopes of the Western Ghats.
• Mangroves grow along coasts in salt marshes, tidal creeks, mudflats and estuaries; in Odisha they occur in the Mahanadi and Brahmani-Baitarani deltas, of which Bhitarkanika is the best known.
• Tropical deciduous forest is the natural vegetation covering the largest share of India's area.

• Putting mangrove anywhere except the coastal end of the transect.
• Confusing thorn forest with desert scrub — thorn forest is the wetter of the two and lies east of the true desert.
• Answering from the states named rather than from the rainfall gradient; the option order is what is being tested.

As a transect between two named towns, as a straight sequence of vegetation belts by rainfall, or as a match of forest type to state.

• practice — not a real PYQ

  Which one of the following forest types occupies the largest area in India?

  • (a)Tropical evergreen forest
  • (b)Tropical deciduous forest
  • (c)Tropical thorn forest
  • (d)Montane forest

  Answer(b) Tropical deciduous forest — the monsoon forests of the moist and dry deciduous belts together cover more of India than any other type.

• practice — not a real PYQ

  Bhitarkanika, the second largest mangrove tract on India's mainland, lies in which one of the following states?

  • (a)Andhra Pradesh
  • (b)West Bengal
  • (c)Odisha
  • (d)Tamil Nadu

  Answer(c) Odisha — Bhitarkanika stands in the Brahmani-Baitarani delta of coastal Odisha, north of the Mahanadi mouth.