ISA Tree Risk Assessment Questions and Answers

Question 1

An arborist performs a detailed, 360-degree visual inspection of a tree from the ground, using a mallet to sound the trunk and a probe to investigate a potential cavity.
According to ISA standards, this type of on-site evaluation is best described as which level of assessment?

Accepted Answer

Level 2 (Basic)

Answer

Level 1 (Limited Visual)

Answer

Level 3 (Advanced)

Answer

Preliminary Hazard Survey

Question 2

In the ISA Tree Risk Assessment Qualification (TRAQ) methodology, the final risk rating is determined by combining three primary components. Which of the following correctly identifies these components?

Accepted Answer

Likelihood of failure, likelihood of impacting a target, and consequences of failure

Answer

Defect severity, tree species, and site conditions

Answer

Tree height, canopy spread, and proximity to structures

Answer

Load factors, tree health, and soil stability

Question 3

An arborist identifies a mature tree with a significant structural defect. However, the tree is located in a remote, fenced-off wildlife preserve with no trails or public access. Despite the defect, the arborist assigns a low overall risk rating. What is the most likely justification for this low rating?

Accepted Answer

The likelihood of the tree or its parts impacting a target is negligible

Answer

The tree has excellent adaptive growth around the defect

Answer

The species is known to compartmentalize decay effectively

Answer

The arborist plans to mitigate the defect with cabling

Question 4

When assessing codominant stems, the presence of included bark in the union is a significant concern primarily because it:

Accepted Answer

Creates a weak attachment by preventing strong, interlocking wood tissue from forming.

Answer

Attracts wood-boring insects that further weaken the tree.

Answer

Restricts the flow of water and nutrients to the competing stems.

Answer

Is a definitive sign of an aggressive fungal pathogen.

Question 5

A Level 2 assessment of a high-value historic oak reveals suspected internal decay, but the extent cannot be determined visually. To gather more detailed, quantitative data about the amount of solid wood remaining, which of the following would be the most appropriate next step?

Accepted Answer

Proceed with a Level 3 assessment using sonic tomography.

Answer

Immediately recommend removal to eliminate all risk.

Answer

Use an increment borer to extract multiple core samples for visual review.

Answer

Prescribe a heavy crown reduction to reduce weight on the trunk.

Question 6

Which of the following is an example of 'target management' as a tree risk mitigation strategy?

Accepted Answer

Relocating a park bench from underneath a tree's dripline.

Answer

Pruning a heavy limb to reduce its weight.

Answer

Installing a dynamic cable system to support weak branches.

Answer

Applying a fungicide to treat a root rot pathogen.