Q. When the bark of a tree is removed in a circular fashion all around near its base, it gradually dries up and dies because (UPSC Prelims 2011)
Answer: Roots are starved of energy
Notes: The correct answer is [B] Roots are starved of energy.The "bark" of a tree includes the Phloem, which is a thin layer of living tissue just beneath the hard outer surface. The Phloem is responsible for transporting sugars (energy) created in the leaves through photosynthesis down to the roots.

• Girdling (The Circular Cut): When you remove a ring of bark all the way around the base, you are severing the Phloem pipeline.
• Energy Blockage: The roots, which stay underground and cannot perform photosynthesis, depend entirely on the leaves for food. Once the Phloem is cut, the roots stop receiving energy.
• Gradual Death: The roots eventually starve and die. Once the roots die, they can no longer absorb water or nutrients, which causes the upper parts of the tree to dry up and die as well.