Risk Assessment Flashcards

A risk assessment matrix typically combines which two primary factors to determine overall risk rating?

Answer: Likelihood of failure and consequences of failure

The ISA risk matrix crosses likelihood of failure with consequences of failure to produce an overall risk rating.

Which of the following is an example of a dynamic load that increases tree risk?

Answer: High wind gusts

High wind gusts are a dynamic, time-varying force that dramatically increase the risk of tree failure.

What does 'occupancy rate' refer to in tree risk assessment?

Answer: How frequently the target zone is occupied by people or vehicles

Occupancy rate describes how often a target (person, vehicle, structure) is present in the impact zone.

A CTSP observes a mushroom fruiting body (conk) at the base of an elm tree. What is the most appropriate interpretation?

Answer: It indicates active root or butt rot, raising structural concern

Conks at the base indicate active decay fungi breaking down root or butt wood, which can seriously compromise stability.

In the ANSI A300 risk management framework, which action is most appropriate for a tree rated as 'extreme' risk?

Answer: Take immediate mitigating action (removal or pruning)

Extreme risk trees require immediate action—typically removal or significant corrective pruning—to eliminate the hazard.

Which tree defect is most difficult to detect during a standard Level 1 (walkby) visual assessment?

Answer: Internal decay not visible at the surface

Internal decay produces no external symptoms until advanced stages, making it nearly invisible during a basic visual inspection.

A property owner asks a CTSP to assess a tree growing next to a school's main entrance. How does target occupancy affect the risk rating?

Answer: High occupancy raises the consequences of failure, increasing overall risk

High occupancy increases the likelihood that failure will harm someone, elevating the consequences and overall risk rating.