The classification of Indian forests prepared by Champion and Seth in 1968 is based mainly on:

The correct answer is D, Red sandal. Red sanders, or red sandalwood, is a tree of the dry deciduous forest and grows almost entirely in the Seshachalam and Palakonda hills of the Eastern Ghats in Andhra Pradesh, where it is prized for its dark red heartwood; it is not a thorn forest species. Options A, B and C are all classic trees of the tropical thorn forest, which grows in the semi-arid belt receiving less than 70 centimetres of rainfall. Khair, the catechu tree, yields the katha used in paan. Keekar and babool are names for the acacia that dots the plains of Rajasthan, Haryana and western Uttar Pradesh. All three carry thorns, small leaves and long tap roots, the standard adaptations for a dry habitat, while red sanders is a taller tree of a moister and shadier forest type.

The correct answer is C, Deciduous forest. Tropical deciduous forest is called monsoon forest because it is the natural vegetation of the monsoon climate, growing where rainfall lies between 70 and 200 centimetres and where a marked dry season follows the rains. Its trees shed their leaves for six to eight weeks in the dry months to save water, and it is the most widespread forest type in India, yielding teak, sal, shisham and sandalwood. Options A and B, rain forest and equatorial forest, describe the evergreen forest of the heavy rainfall belt above 200 centimetres, which has no leafless season at all. Option D, mountain forest, is classified by altitude rather than by the rainfall regime and changes from oak and chestnut through pine and deodar to alpine meadow as one climbs, so it is not tied to the monsoon rhythm.

The correct answer is B, Reserved forests. Indian forests are classified administratively into reserved, protected and unclassed forests, and the first two together are described as the permanent forest estate, that is land maintained permanently for timber and other forest produce and for the protection of soil and water. Reserved forests are the most valuable of the three and enjoy the strictest protection, with grazing and cultivation prohibited or closely regulated. Option A, unprotected forests, is not one of the recognised administrative classes at all. Option C, unclassed forests, covers the remaining wooded land, a great deal of it owned by communities and private persons in the north-east and in Gujarat, and it lies outside the permanent estate. Option D, community forests, again describes ownership rather than an administrative class, and such land usually falls within the unclassed category.

The correct answer is C, Mautam. Melocanna baccifera, the muli bamboo, covers large tracts of Mizoram and the neighbouring hills and flowers only once in about half a century, after which the whole stand dies. The flowering produces a flood of protein rich seed, rats multiply on it, and when the seed is finished the swarm moves into the paddy fields and destroys the crop, causing the famine that Mizo tradition calls mautam. Option A, the Chalisa famine, struck northern India in 1783, in the Vikram Samvat year forty, and had nothing to do with bamboo. Option B, Upper Doab, names a region between the Ganga and the Yamuna and not a famine of this kind. Option D, Doji Bara, is the skull famine that hit the Deccan and Hyderabad in the 1790s. Only mautam is tied to the flowering cycle of a bamboo species.

The correct answer is A, tropical evergreen forests. These forests grow where annual rainfall exceeds 200 centimetres, on the windward western slopes of the Western Ghats, in the Andaman and Nicobar Islands, in upper Assam and along the hills of the north-east. Because rain falls through most of the year, the trees have no fixed leaf fall, the canopy stays green and the forest is tall and layered; rosewood, mahogany, ebony, aini, cinchona and rubber are its commercial species. Option B, thorn forests, grows on less than 70 centimetres of rain and carries babool, khair and khejri instead. Option C, alpine vegetation, is found above about 3,000 metres in the Himalaya and consists of silver fir, juniper, birch and rhododendron, and then of grasses. Option D, dry deciduous forest, receives 70 to 100 centimetres and gives tendu, palas, amaltas and bel.