Certified Arborist Test 2025 – 400 Free Practice Questions to Pass the Exam

The assertion that most soil organisms are beneficial and do not cause disease or decay in tree roots is actually false. While many soil organisms indeed play vital roles in the ecosystem, such as aiding in nutrient cycling and enhancing soil structure, there are also pathogens among them that can negatively affect tree health.

Specific fungi, bacteria, and nematodes can be pathogenic and contribute to root diseases, decay, and overall decline of trees. For example, certain species of fungi are responsible for root rot diseases that can severely weaken or kill trees. Therefore, it is important to recognize that while beneficial organisms are plentiful, the presence of harmful pathogens is also significant in the soil ecosystem surrounding trees.

This understanding emphasizes the complexity of soil biology and the diverse interactions that can occur, leading to both beneficial and harmful effects on trees. It highlights the need for careful monitoring of soil health and tree vitality to ensure that beneficial organisms thrive while managing or mitigating the impacts of pathogenic species.