Tree Risk & Management Flashcards

Which term describes the probability that a specific tree failure will occur within a defined time period?

Answer: Likelihood of failure

Likelihood of failure is the probability that a tree part or whole tree will fail under a given set of conditions.

A 'target' in tree risk assessment refers to:

Answer: People, property, or activities that could be harmed by tree failure

A target is any person, property, or activity in the vicinity of the tree that could be injured or damaged if the tree or a part of it fails.

When assessing tree risk, 'occupancy rate' refers to:

Answer: How often a target is present in the impact zone

Occupancy rate describes how frequently a target (person, vehicle, etc.) is present in the area where it could be struck by a failing tree part.

Which of the following best describes 'residual risk' in tree risk management?

Answer: Risk that remains after mitigation measures are implemented

Residual risk is the level of risk that remains after risk mitigation treatments or actions have been applied to a tree.

A tree with a large stem cavity but no visible crown symptoms would best be evaluated using:

Answer: Advanced assessment tools such as resistograph or sonic tomography

Advanced assessment tools like resistographs and sonic tomography help quantify internal decay that may not be apparent from external visual inspection.

The 'wind-sail effect' is most relevant when evaluating which tree defect?

Answer: Excessive crown size relative to root system

A large crown relative to the root plate creates a high wind-sail effect, increasing the mechanical load on potentially compromised roots.

Under ISA BMP guidelines, which action is appropriate when a tree is rated as 'extreme' risk?

Answer: Take immediate action such as removal or crown reduction before next use

An extreme risk rating requires immediate action, typically removal or significant risk mitigation, before the target area is used again.