10.4 Tree Analysis and Obvious Defects

Inspecting the Tree from Roots to Crown

Tree analysis is the part of risk assessment that focuses on the tree itself. Within the assigned level of assessment, the arborist observes roots, root collar, trunk, scaffold branches, crown, foliage, deadwood, and signs of decay or stress. The exam may ask which defect is most concerning, what should be inspected next, or what recommendation fits the finding.

Obvious defects are conditions that can be seen or reasonably detected during the assessment. They include dead branches, hanging broken limbs, cracks, splits, cavities, decay indicators, weak unions, included bark, cankers, root plate movement, severed roots, girdling roots, basal wounds, and fungal fruiting bodies. The presence of a defect is only the beginning. Its significance depends on size, location, target, load, species, and extent.

Crown condition gives clues but does not tell the whole story. Sparse foliage, dieback, small leaves, or epicormic growth may reflect root stress, drought, pests, disease, or age. A full crown does not prove structural soundness. A tree can have green leaves and still contain a crack, weak union, or compromised root plate.

The root collar deserves careful attention. Soil or mulch against the trunk can hide decay, wounds, girdling roots, or flare problems. Fungal fruiting bodies near the base can indicate decay, but species identification and location matter. The exam usually does not require laboratory certainty; it requires recognizing that basal decay indicators can be important and may justify further assessment or mitigation.

Defect Interpretation Questions

1. What part of the tree contains the defect?
2. Is the defect active, recent, expanding, or long-standing?
3. How large is the defective part and what load does it carry?
4. What target is within striking distance?
5. Does the current assessment level provide enough information?
6. What action would reduce risk without exceeding the arborist's scope?

Scenario: A co-dominant stem has included bark and a crack extending below the union over a driveway. The concern is not merely that the form is imperfect. The crack, union structure, load, and target combine to raise risk. A recommendation might include restricting access, pruning load where appropriate, support system evaluation, advanced assessment, or removal of the whole tree when justified by findings.

Scenario: A cavity is visible on the trunk of an old tree in a low-use area. The best answer is not automatic panic or automatic dismissal. The arborist should consider cavity size and location, remaining sound wood, species response, targets, occupancy, and whether advanced assessment is needed. The recommendation should match the actual risk context.

For study, avoid defect flashcard thinking. A crack is not always the same risk, and a cavity is not always the same outcome. Exam success comes from linking defect, load, target, consequence, and scope.