Ace the Certified Arborist 2025 Exam – Branch Out to Success!

The defect caused by bark being pushed inside the branch union as two branches grow and develop is known as included bark. This occurs when two or more branches grow close together, and as they expand, the bark between them fails to properly grow outward. Instead, it becomes trapped within the branch union, creating a weak area that can lead to structural problems.

Included bark is particularly concerning because it compromises the integrity of the union between the branches. Instead of forming a strong, supportive connection, the trapped bark can create a point of weakness that increases the risk of branch failure, especially under stress from weight or wind. This can result in a higher likelihood of breakage or splitting, making it essential for arborists to recognize and manage this condition in tree care practices.

The other possible defects listed do not pertain to this specific situation. A branch collar refers to the area that forms at the base of a branch and is crucial for healing after pruning. Subordination involves training one branch to dominate or grow more vigorously than another, which is a management practice, not a defect. Lion-tailing refers to a pruning technique that removes inner foliage from a tree's canopy, often leading to other structural issues and is unrelated to the condition of bark trapped between branches.