UPSC Prelims 2021 GS Paper I · Q60 of 98 Geography medium

"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

  1. (a) coniferous forest
  2. (b) dry deciduous forest
  3. (c) mangrove forest
  4. (d) tropical rain forest ✓ UPSC's answer

Why the answer is (d)

• Rapid leaf-litter decomposition, a nearly bare forest floor, and abundant lianas (climbers) and epiphytes rooted on upper branches are hallmarks of the tropical rain forest — option (d).

• Warm, humid conditions year-round let fungi and bacteria break down litter within weeks, so nutrients are locked in living biomass rather than the soil.

• Coniferous forests (a) have thick, slowly decaying needle litter; dry deciduous forests (b) shed leaves seasonally and have few epiphytes; mangroves (c) are tidal swamps with pneumatophores, not epiphyte-rich canopies.

• Hence option (d).

Why the other options are wrong

(a) coniferous forest
Coniferous litter decomposes slowly and forms thick mor humus.
(b) dry deciduous forest
Dry deciduous forests have seasonal litter and few epiphytes.
(c) mangrove forest
Mangroves are tidal swamps, not epiphyte-rich canopies.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2021, held on 10 October 2021. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

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