Correct Answer: Eucalyptus

Solution : The correct option is Eucalyptus .

While the Eucalyptus tree is often referred to as 'green gold' due to its rapid growth and economic benefits, its widespread cultivation has led to significant ecological problems. These include water depletion due to the tree's high water requirements, soil deterioration caused by compounds emitted by Eucalyptus trees, and negative impacts on native flora and fauna due to the displacement of native species and disturbance of local ecosystems. Therefore, despite its economic advantages, the unchecked planting of Eucalyptus trees poses serious ecological risks and challenges.