ISA Tree Risk & Management

Question 1

What is the primary purpose of a tree risk assessment?

Accepted Answer

To assess the health and stability of the tree

Answer

The primary purpose of a tree risk assessment is to systematically evaluate the health, structural integrity, and potential for failure of a tree. This assessment identifies defects, decay, and other conditions that could lead to a branch or the entire tree falling, thereby determining the level of risk it poses to people or property. It informs decisions on necessary mitigation actions.

Question 2

What are the three main factors considered in tree risk management?

Accepted Answer

Likelihood of failure, targets, and consequences

Answer

Tree risk management is based on three main factors: the likelihood of failure (how likely the tree or a part of it is to fail), the presence of targets (what or who could be hit if it fails), and the consequences of failure (the severity of injury or damage that would occur). Assessing these three components allows arborists to quantify and manage the overall risk posed by a tree.

Question 3

How does tree lean affect risk management?

Accepted Answer

It increases the likelihood of failure

Answer

Tree lean significantly increases the likelihood of failure, especially if the lean is severe, sudden, or accompanied by other defects like root plate movement or cracks at the base. A leaning tree experiences uneven stress distribution, making it more vulnerable to wind, storms, or its own weight, potentially leading to uprooting or stem breakage. This compromises its structural integrity.

Question 4

What role does soil compaction play in tree health and stability?

Accepted Answer

Reduces root growth and nutrient absorption

Answer

Soil compaction severely impacts tree health and stability by reducing pore space, which is essential for air and water movement. This limits oxygen availability to roots, inhibits root growth, and hinders the roots' ability to absorb water and nutrients. Compacted soil also makes trees more susceptible to drought stress and reduces their anchorage, increasing instability.

Question 5

What is the purpose of crown cleaning during tree maintenance?

Accepted Answer

To remove unhealthy branches

Answer

Crown cleaning, also known as deadwooding, is a standard tree maintenance practice focused on removing dead, dying, diseased, weakly attached, or interfering branches from the tree's crown. This process improves the tree's overall health, reduces the risk of falling branches, and enhances its aesthetic appearance by eliminating hazardous or unsightly wood.

(ISA) ISA Certified Arborist Practice Test

(ISA) ISA Certified Arborist Practice Test

ISA Tree Risk & Management