ISA Certified Arborist Practice Exam 2025 – All-in-One Resource for Comprehensive Exam Success!

The process of shedding leaves in deciduous trees is known as abscission. This term describes the physiological changes that occur in a plant that lead to the separation of leaves from the stem or branch, facilitating seasonal changes and water conservation during unfavorable conditions. Abscission involves a well-coordinated process involving hormones, cellular changes, and environmental cues, ensuring that trees can efficiently manage their resources.

Dormancy refers to a period when a plant's growth and metabolic processes slow down, which often occurs during winter; it is not directly related to the leaf-shedding process itself. Deciduation describes a broader context of shedding, often used in the reproductive processes of some plants and animals, which is less specific to trees and leaf drop. Senescence, on the other hand, refers to the aging process of a leaf or plant parts before abscission occurs, leading to visual changes and eventual drop; however, it does not specifically define the act of shedding leaves. Therefore, abscission is the most accurate term for this natural process in deciduous trees.