UPSC CSE Prelims
Question 30
When the bark of a tree is removed in a circular fashion all around near its base, it gradually dries up and dies because
View correct answer and explanation
Correct answer: B
Correct Option: B
Explanation: Circular removal of the bark and inner phloem (girdling) prevents downward transport of sugars from leaves; roots starve and the tree eventually dies.
Option-wise Analysis:
A: Incorrect - Xylem water transport may initially continue after bark girdling.
B: Correct - interruption of phloem starves roots of photosynthetic carbohydrates.
C: Incorrect - Soil-microbe infection is not the necessary mechanism.
D: Incorrect - Oxygen reaches roots mainly through soil pores; bark removal does not directly stop this.