Forestry and Plant Sciences

Spring is considered as the flowering season. This is the period when there is growth of the floral buds which are formed at the apex of the vegetative shoots. Generally, there is a flow of sugar from the source (leaves) to sink end (roots). Due to the increase in the activity in the apex regions of the plant, there is consumption of food in the leaves. Hence, the food to the flower buds is supplied by the roots. 

Evergreen plants retain their green leaves throughout the year, rather than shedding them seasonally.

A structure with walls and roof generally made of transparent material generally used to grow plants under controlled climatic conditions is called greenhouse. It possess all the desirable qualities like ventilation, heating, carbon dioxide enrichment etc. Material used can be of glass or plastic. 

Sequoiadendron giganteum is the sole living species in the genus Sequoiadendron. Giant sequoia specimens are the most massive trees on Earth.The name "Wellingtonia" has persisted in England as a common name, also known as giant redwood, sierra redwood, sierran redwood, Wellingtonia  or simply big tree.

The wood of several Gymnosperms, particularly those of conifers is used in paper industry. Conifers wood is used as a structural timber and for making furniture.

Sequoia is the largest species on the planet. It belongs to the family Cupressaceae of Coniferales.

Conifers that belong to the largest and the economically most important component group of the gymnosperms and are known to consists of both living and fossil taxa. Represented by a number of species, the stems of conifers are composed of a woody axis containing primitive water- and mineral-conducting cells- tracheids. All living conifers are woody plants, and mostly evergreen trees, with a monopodial growth form.

Ginkgo is considered an evolutionary link or intermediate form between cycads and conifers due to its unique combination of primitive and derived traits.

Ginkgo biloba is commonly known as the Maidenhair tree. It is a unique species of gymnosperm with no living relatives.

Forest industries are those which are dependent on the materials that are derived from the forestry. Paper, rubber and resin industries are dependant on forests for their raw material. But the raw material for aluminium is bauxite which is found in the earth's crust.

Paper mills generally use wood from bamboo, eucalyptus and subabul trees. Subabul wood is most widely used now. Besides wood, a large number of chemicals such as common salt, caustic soda and so on are also used in different stages of paper making. 

Tall trees of range 15m and above have strong buttress because they need to support the whole plant body and its top part from falling or swaying in the extreme environmental conditions.

For the canopy to spread over a large area the root system also has to be robust so as to provide enough nutrients and anchorage. Wide spreading and deep roots are tap root systems that are characteristic to dicotyledonous plants.

Plants growing on the forest floor (understorey) are adapted to lower Sunlight intensity or are shade loving. This is because, the dense canopy does not allow enough light to penetrate through and reach the forest floor. Light is the limiting factor for these plants and therefore, they are adapted to survive under low light conditions. Moisture availability and related adaptations are not of consideration. Thus, the correct answer is option B.

This plant is nowadays being planted on a large scale under social - forestry. They used as a wind breaks, fire breaks fodder etc.