Certified Arborist Practice Exam

Cabling primarily helps to support dynamic defects in trees. Dynamic defects are issues like weak branch unions, codominant stems, or branches that are under stress from wind or weight. These can result in the potential for the branch to fail. Cabling provides additional support and rigidity, allowing the tree to maintain its structure while reducing the risk of harm to the tree or nearby structures.

In terms of the other options, dead-end grips refer to a type of fastener that may not apply directly to the context of tree cabling. A thimble is a component used within cabling systems but doesn’t represent a defect itself. Reduction defects usually refer to issues where limbs are pruned back, which is a different context than what cabling is intended to address. Therefore, while cabling addresses the needs presented by dynamic defects, the other options don't coincide with the direct functions of cabling in terms of tree support.