Certified Arborist Test Tree Risk 4 — Questions and Answers
Question 1: What are the three components of tree risk assessment?
- Height, width, and age
- Likelihood of failure, likelihood of impacting a target, and consequences of impact (Correct answer)
- Species, location, and soil type
- Trunk diameter, crown spread, and root depth
Correct answer: Likelihood of failure, likelihood of impacting a target, and consequences of impact
Tree risk is evaluated by assessing: (1) how likely the tree or part is to fail, (2) how likely that failure would hit a target, and (3) the severity of consequences if impact occurs.
Question 2: What risk rating indicates a tree that poses an imminent threat and requires immediate action?
- Low risk
- Moderate risk
- High risk
- Extreme/imminent risk (Correct answer)
Correct answer: Extreme/imminent risk
Extreme or imminent risk means failure is very likely, a target is present, and consequences could be severe (injury/death, major property damage). Immediate mitigation is required.
Question 3: Co-dominant stems with included bark are considered a significant risk factor because:
- They produce too much shade
- The bark between stems prevents strong wood union, making splitting more likely (Correct answer)
- They attract more insects
- They grow faster than single-leader trees
Correct answer: The bark between stems prevents strong wood union, making splitting more likely
Included bark between co-dominant stems acts as a wedge, preventing the formation of strong connective wood. This creates a structural weakness where the stems can split apart, especially under load.
Question 4: What is the 'target zone' in tree risk assessment?
- The area where pruning cuts should be made
- The area that could be struck by a failing tree or branch, where people or property are present (Correct answer)
- The root zone of the tree
- The area selected for pesticide application
Correct answer: The area that could be struck by a failing tree or branch, where people or property are present
The target zone encompasses all areas where people, vehicles, structures, or other valued items could be struck if the tree or a part of it failed. No target = lower risk regardless of tree condition.
Question 5: Which visual symptom is the strongest indicator of potential whole-tree failure?
- Minor leaf discoloration
- Severe lean with recent root plate lifting and cracked soil (Correct answer)
- One dead branch in the upper crown
- Epicormic sprouting on the trunk
Correct answer: Severe lean with recent root plate lifting and cracked soil
A severe lean combined with heaving root plate and cracked soil indicates the root system is failing and the tree may fall. This is one of the most critical risk indicators requiring immediate action.
Question 6: How does the presence of a target affect the risk rating of a tree with structural defects?
- It has no effect on the rating
- It significantly increases the risk rating (Correct answer)
- It decreases the rating because targets can be moved
- Targets only matter for trees over 50 feet tall
Correct answer: It significantly increases the risk rating
A structurally compromised tree over a frequently occupied area (playground, sidewalk, parking lot) receives a much higher risk rating than the same tree in an unoccupied area.
Certified Arborist Test Tree Risk 4
What are the three components of tree risk assessment?