ISA Certified Arborist Practice Exam

The term for elements like copper, chlorine, and boron that are required by trees in large amounts is macronutrient. Macronutrients are essential nutrients that plants need in relatively high quantities for their growth and development. While the term is often associated with primary macronutrients such as nitrogen, phosphorus, and potassium, it can also include secondary macronutrients, which are needed in somewhat lesser amounts but are still crucial for the plant’s physiological functions.

These nutrients play various roles, such as forming enzymes, contributing to photosynthesis, and aiding in the synthesis of nucleic acids. Trees that lack sufficient levels of these elements may exhibit deficiencies that can impact their health and overall growth.

In this context, it's important to differentiate these from other terms. Injections refer to the method of administering nutrients directly into a tree and do not describe the nutrients themselves. Infiltration rate pertains to the speed at which water enters the soil, which affects water availability but is unrelated to nutrient classification. Water holding capacity refers to the soil's ability to retain water, which is important for nutrient uptake but does not describe the nutrients themselves. Thus, macronutrient is indeed the appropriate term for the elements required in larger amounts by trees.