ISA Certified Arborist Practice Exam

What is an effective method for controlling invasive tree species?

1. Planting additional native trees

2. Mechanical removal or chemical herbicides

3. Watering the invasive trees regularly

4. Encouraging local wildlife to consume the invasives

The correct answer is: Mechanical removal or chemical herbicides

The most effective method for controlling invasive tree species is through mechanical removal or the application of chemical herbicides. Mechanical removal involves physically cutting down or uprooting the invasive trees, which can significantly reduce their population. This method is direct and ensures that the invasive trees can no longer grow or spread in the area. Chemical herbicides can also be utilized to target and eliminate invasive species. These products are specifically designed to kill unwanted plants and can be applied in various forms, including foliar sprays or soil treatments. When applied correctly and at the appropriate time, herbicides can effectively reduce the density of invasive trees and allow for better growth conditions for native species. In contrast, planting additional native trees may help restore biodiversity, but it does not address the immediate problem of the invasive species already occupying the area. Without first managing the invasive trees, planting natives could lead to competition for resources and may not result in a healthy ecosystem. Watering invasive trees regularly would likely promote their growth and spread rather than control their population. Encouraging local wildlife to consume the invasives may help in some cases, but it is not a reliable or comprehensive method for managing invasive trees, as not all wildlife will feed on these species, and their populations may not be sufficient to control the invas