ISA Certified Arborist Practice Exam 2026 – All-in-One Resource for Comprehensive Exam Success!

Crown reduction specifically refers to the method of selectively reducing the size of the tree's crown by cutting back the branches to lateral branches that are at least one-third the diameter of the cut branch. This technique is used to maintain the health and structural integrity of the tree while also reducing its height and spread. It is a common practice employed to manage tree growth, improve safety by preventing branches from coming into contact with structures or power lines, and enhance the aesthetic value of the tree while still allowing it to maintain its natural form.

The other choices either describe different aspects of tree maintenance or do not accurately define crown reduction. For instance, removing dead branches does contribute to tree health but does not involve the selective shaping or size reduction that crown reduction implies. Enhancing sunlight penetration and improving tree shape may be outcomes of proper pruning but they do not define the specific practice of crown reduction.