Certified Arborist Practice Test

Included bark is a defect that occurs when the bark of a branch becomes embedded between two branches or between a branch and the main trunk as they grow. This situation arises from the growth habit of the tree, where the branches grow closely together without sufficient space to develop separately. As the tree matures, the included bark can create a weak point in the branch union, leading to structural issues. It restricts the natural movement and expansion of the bark, which can hinder the proper function of the stem cells underneath the bark and prevent normal healing processes.

This defect is particularly concerning because it can lead to the eventual splitting or breaking of the branches during storms or under heavy loads, as the included bark lacks the strength that a properly formed branch union would provide. Understanding this defect is crucial for arborists when evaluating the health and stability of trees, especially in urban areas where they may be subjected to additional stress.