Tree Risk & Management Flashcards

In the ISA Tree Risk Assessment framework, the three components that combine to determine risk are:

Answer: Likelihood of failure, likelihood of impact, and consequences of failure

ISA defines risk as the combination of the likelihood of failure, the likelihood that failure would strike a target, and the consequences if it does.

A two-year-old pruning wound on a large-diameter branch that shows little to no callus formation most likely indicates:

Answer: Reduced tree vigor or a systemic health problem

Slow or absent callus development two years after pruning suggests compromised tree vigor, possibly due to disease, root damage, or poor site conditions.

Which condition most increases the likelihood that a codominant stem union will fail?

Answer: Included bark visible in the union combined with a high aspect ratio

Included bark eliminates the interlocking wood grain that provides strength, and a high aspect ratio (narrow union relative to stem diameter) further reduces structural integrity.

Which type of structural support system is designed to limit the movement of branches rather than to bear the full load of the crown?

Answer: Dynamic (flexible) cabling

Dynamic cabling systems use flexible cables or straps that allow movement and load sharing while limiting excessive sway that could cause branch failure.

When a tree is located in a lightning protection zone, proper grounding conductors should be installed to:

Answer: Carry lightning energy safely into the ground and protect roots from explosive steam damage

Lightning protection systems route electrical energy to earth via grounding conductors, preventing explosive vaporization of moisture in trunk wood and reducing root damage.

What does the term 'CODIT' stand for in arboriculture?

Answer: Compartmentalization of Decay in Trees

CODIT (Compartmentalization of Decay in Trees) is the model describing how trees wall off decay through four chemical and structural barriers.

A tree leans significantly toward a high-occupancy target. The arborist finds healthy root flare and no decay. The MOST important next assessment step is:

Answer: Measure the lean angle and compare to the root plate radius to assess overturn potential

Quantifying lean angle relative to root plate size helps determine whether the center of gravity has shifted enough to create an unacceptable overturn risk.