RAS question
Tropical thorn forests in India are found in:
Correct answer: (D) Rajasthan, Gujarat, Punjab, Haryana.
Tropical thorn forests in India are found in Rajasthan, Gujarat, Punjab and Haryana, where annual rainfall is generally below 70 cm.
Explanation
Tropical thorn forests are linked to India's dry north-western belt, not to coasts or islands. eGyanKosh, Unit 10: Phytogeography places this vegetation in areas with less than 70 cm of rainfall and notes thorny trees, bushes, scattered tree cover, long roots, succulent stems, and thick, small leaves that reduce moisture loss. Its Indus Plain section specifically lists Gujarat, Delhi, Rajasthan, Haryana and Punjab, describes dry regions, plains, deserts and irrigated lands, and says the vegetation consists of tropical thorn forests and grasslands, with tropical thorny and dry-shrub forms. Babool, Khejri, cactus and Euphorbia are xerophytic plants adapted to the Thar Desert fringe and adjoining semi-arid areas.
Why the other options are wrong
- (A) eGyanKosh, Unit 10: Phytogeography associates coastal areas with mangrove vegetation, while thorn forests are tied to dry regions with rainfall generally below 70 cm.
- (B) Tropical thorn forests are not placed in island territories; they belong to the north-western dry belt, including Rajasthan, Gujarat, Punjab and Haryana.
- (C) Desert regions are part of the dry belt, but the distribution also includes plains, irrigated lands and semi-arid areas, so it is not only desert.
Concept
This tests the Indian vegetation classification under Environment and Ecology, especially the link between rainfall, aridity and xerophytic adaptations. RAS repeats this concept because Rajasthan's Thar fringe makes tropical thorn vegetation a core local ecology topic.