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

Identifying indicators of decay in trees is crucial for assessing their health and structural integrity. Cellulose serves as a primary structural component of a tree's cell walls, and its breakdown is often a sign of decay. When fungi invade a tree, they use enzymes to decompose cellulose, which affects the tree's strength and stability. Therefore, a notable reduction in the cellulose content can indicate advanced decay within the wood.

The other indicators, such as the potential for failure, root collar excavation, and reaction wood, although relevant in certain contexts, do not directly correlate as clear indicators of decay itself. The potential for failure focuses more on the likelihood of structural issues arising due to various factors, including decay, but does not specifically indicate where decay might be present. Root collar excavation is a diagnostic method used to investigate root health and other issues, and reaction wood is a response to mechanical stress rather than a direct indicator of decay.

Thus, understanding cellulose breakdown as a sign of decay is essential for tree health assessment and management.