Previous Year Question

Eucalyptus is a fast-growing tree predominantly native to Australia and is commonly known as Nilgiri in India. It is used for timber, the paper industry, fuel, and commercial plantations. Its major environmental concerns under certain conditions include high water consumption, impacts on native vegetation, and reduced biodiversity. Particularly in arid and semi-arid regions, large-scale Monoculture Plantations of Eucalyptus can create ecological problems.

The water-related characteristics of Eucalyptus are associated with its rapid growth and Transpiration. It absorbs water from the soil and releases it into the atmosphere through its leaves. High-density plantations may reduce soil moisture and Groundwater Recharge in certain regions. A study published in 2020 on Kolar district in Karnataka associated Eucalyptus plantations and land-use changes with an approximately 30% reduction in surface runoff and groundwater recharge. However, actual water consumption depends on climate, tree species, soil characteristics, and water availability.

Allelopathy is another important ecological process associated with Eucalyptus. Chemical compounds released from the leaves and other residues of certain Eucalyptus species can affect the germination and growth of neighbouring plants. Additionally, replacing natural forests or grasslands with Eucalyptus Monoculture Plantations can reduce the diversity of native vegetation and wildlife. However, not all Eucalyptus species or plantation conditions produce the same negative effects. With appropriate site selection and management, Eucalyptus can also provide commercial and environmental benefits.

Among the other options, Banana (Musa) is actually a Giant Herb rather than a true woody tree. Neem (Azadirachta indica) is an important tree of the Indian subcontinent, used for medicinal products, biopesticides, and plantation purposes. Babool (Acacia nilotica) is a tree found in dry regions and is useful for fodder, fuel, and land conservation. Native Babool should be distinguished from Vilayati Babool (Prosopis juliflora), as the latter acts as an Invasive Species in many regions and adversely affects local biodiversity.