Forestry and Plant Sciences

• Afforestation is the process of planting trees, or sowing seeds, in a barren land devoid of any trees to create a forest. The term should not be confused with reforestation, which is the process of specifically planting native trees into a forest that has decreasing numbers of trees.
• Indigenous species refers to species originating or occurring naturally in a particular place(native).
• Hence Afforestation should be with Indigenous species because they are easily available and have a high growth rate.
• So, the correct answer is  'Indigenous species'.

Reforestation means replanting of forest trees in areas, which were once having dense forests but the forests were later on destroyed by cutting of trees in large numbers. Afforestation is different from reforestation. Afforestation is planting of trees in new areas, which were not previously under forest cover. Typically, waste lands or land other wise not previously having forest cover is selected. Indigenous species are more suited for this purpose because they are well adapted to local climatic and soil conditions. These species are already acclimatized to local conditions.

Knots are common blemishes in trees, often causing lumps or holes within the trunk of the tree itself. In most cases knots are caused by the natural growth of the tree, though the specific circumstances under which they form determines how they will appear. As a tree grows and increases the circumference of its trunk, the growing trunk begins to overtake the branches that grow out from it. Knots form around these branches, building up trunk material as the tree continues to expand. Since, the branches are still growing as they are overtaken by the trunk, the knot that forms is solid and contains living wood throughout. The wood of the knot is typically tougher than the surrounding wood and may form a bulge around the branch emerging from its center. So, knots are formed in wood due to bases of the branches get buried in main stem and not because leaf scars, insect bites and injuries. 
Therefore, the correct answer is option B.

In dicotyledonous trees, growing in temperate regions, due to maximum seasonal variations two types of secondary xylems are formed, spring or early wood and autumn wood or latewood. These two kinds of wood together form into a ring of wood called annual rings. These annual rings are useful in indicating the age of the trees.

So, the correct option is ‘Dicot of temperate regions’.

Leucaena leucocephala (Subabul) is a social foresting species with multiple utility like green manure, biomass production, food for humans, pulpwood for paper industry.

Reforestation is the natural or intentional restocking of existing forests and woodlands that have been depleted, usually through deforestation. Reforestation activities promote the gradual depletion of CO2 from the atmosphere through absorption during photosynthesis.

Theobroma cacao, also called the cacao tree and the cocoa tree, is a small (4–8 m (13–26 ft) tall) evergreen tree in the family Malvaceae, native to the deep tropical regions of the Americas. Its seeds, cocoa beans, are used to make chocolate liquor, cocoa solids, cocoa butter and chocolate.

Afforestation is the process of planting trees in an area that did not previously have forest cover or has been cleared for a long time. It is a key strategy for increasing forest cover.

Jhum is the traditional name for slash-and-burn agriculture practiced in Northeast India, where trees are cut, burned, and crops are grown using the nutrient-rich ash.

Dalbergia (such as Dalbergia sissoo) is highly valued for its timber and is generally considered a premium wood rather than a bad firewood. However, in the context of specific biology curricula, it is often cited as poor fuel compared to others due to its high value as timber.

The products which are obtained from the forests include the wood, gum, resins, tannins, sealing wax, etc. The plywood is the sheet of the wood which is used for furniture and house construction. The sealing wax is obtained from the bugs which live on trees. The gum is obtained from the secretions of the trees. The kerosene is not a forest product which is obtained from the distillation of the fuel from the ground. 

Energy plantation means growing selected species  of  trees and shrubs which are  harvestable in a comparably  shorter time and are  specifically meant for fuel. The fuel wood may be used either directly in wood burning stoves and boilers or processed into methanol, ethanol and producer gas. These plantations help provide wood either for cooking in homes or for industrial use, so as to satisfy local  energy  needs in a decentralized manner.

Dalbergia latifolia is an economically important timber species native to low elevation tropical monsoon forests of eastern India. Some common names in English are blackwood, bombay blackwood. Wood from Dalbergia latifolia tree is used in premium furniture making and cabinetry, as veneer, as plywood, for outdoor furniture.

Dalbergia sissoo is a highly valued hardwood timber species, providing an additional income source in agroforestry systems, mostly in India and Pakistan. The establishment of D. sissoo plantations for wood production can be an attractive proposition in economic terms. Most plantations are managed primarily for timber, with fuelwood as a secondary product. For fuelwood production in short rotations, several other species may give higher financial returns.