ISA Certified Arborist Practice Exam

A grafted tree is defined as a tree formed by joining parts from two different trees. This horticultural technique involves taking a portion from one plant (the scion) and attaching it to the root system or trunk of another (the rootstock). The primary purpose of grafting is to propagate a desired cultivar while leveraging the favorable characteristics of the rootstock, such as disease resistance, hardiness, or improved nutrient uptake.

This method is commonly used in fruit trees to enhance fruit quality, improve growth performance, and ensure that the new tree retains specific genetic traits. Grafting allows for the combination of the best attributes of both plants, leading to trees that are often more productive and resilient than their non-grafted counterparts.

In contrast, the other options describe different concepts. Genetic modification pertains to alterations made directly to the plant's DNA, while rooting in specific soil types and the definition of a native tree species do not relate to the grafting process. Understanding these differences helps clarify the unique characteristics and purposes of grafted trees in horticulture.