Hazard and Risk Assessment Flashcards
7 cards from real CTSP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Hazard and Risk Assessment flashcards as text
In the ISA Tree Risk Assessment Qualification (TRAQ) framework, which three factors combine to determine overall tree risk?
Answer: Likelihood of failure, likelihood of impact, and consequences
TRAQ defines overall risk as the product of likelihood of failure, likelihood of impact on a target, and the consequences of that impact.
Which condition would most likely place a tree into the 'Poor' structural condition rating?
Answer: Large open cavity occupying more than 30% of the trunk cross-section
A large open cavity removing more than 30% of the trunk's cross-sectional area severely compromises structural integrity.
What is the primary purpose of establishing a tree risk tolerance threshold for a site?
Answer: To define the highest risk level acceptable before mitigation is required
A risk tolerance threshold defines the maximum acceptable risk level, triggering mitigation actions when that level is exceeded.
A street tree with a significant lean over a sidewalk also shows root plate lifting on the tension side. What does root plate lifting indicate?
Answer: Active windthrow failure in progress or high failure potential
Root plate lifting signals that the tree's root system is losing anchorage and the tree may be in the early stages of windthrow failure.
Which of the following best describes a 'residual risk' after mitigation measures have been applied?
Answer: The remaining risk that still exists after mitigation actions are completed
Residual risk is the level of risk that remains after mitigation measures such as pruning, cabling, or removal have been implemented.
An oak tree shows conks of Ganoderma species at the base. How does this finding affect risk assessment?
Answer: It indicates significant root and butt rot, elevating failure likelihood
Ganoderma species cause white rot of roots and the butt, substantially weakening the tree's foundation and increasing failure likelihood.
When quantifying consequences in tree risk assessment, which target classification carries the highest weight?
Answer: Permanently occupied residence or frequent-use area
Permanently occupied or frequently used structures and areas carry the highest consequence weight due to constant human presence.