CATS Urban Tree Risk Assessment & Mitigation 1 — Questions and Answers
Question 1: What is the primary purpose of a Level 1 tree risk assessment according to ISA standards?
- A visual assessment from a limited perspective, typically walking or driving by, to identify obvious hazards (Correct answer)
- A detailed climbing inspection of every branch and limb
- A laboratory analysis of wood samples for decay organisms
- An aerial drone survey of the entire tree canopy
Correct answer: A visual assessment from a limited perspective, typically walking or driving by, to identify obvious hazards
A Level 1 (Limited Visual) assessment is a walk-by or drive-by survey used to identify trees with obvious structural defects or conditions that pose immediate risk, often used after storms or for large populations of trees.
Question 2: Which of the following is a common indicator of internal wood decay in a standing tree?
- Fruiting bodies (conks or mushrooms) growing on the trunk (Correct answer)
- Dense foliage throughout the canopy
- Bark that is thick and deeply furrowed
- Strong new growth at branch tips
Correct answer: Fruiting bodies (conks or mushrooms) growing on the trunk
Fungal fruiting bodies growing on a tree's trunk or root flare are a reliable external indicator of internal wood decay, as they are the reproductive structures of wood-decomposing fungi.
Question 3: What does the term 'target' refer to in tree risk assessment?
- A person, structure, or area that could be struck by a failing tree or branch (Correct answer)
- The specific tree being evaluated for risk
- The ideal pruning cut location on a branch
- The root zone where fertilizer should be applied
Correct answer: A person, structure, or area that could be struck by a failing tree or branch
In risk assessment, the target is anything of value (people, property, vehicles, infrastructure) that would be affected if the tree or part of it were to fail. No target means no risk, regardless of the tree's condition.
Question 4: What is the recommended response when a certified arborist identifies a tree with a high risk of imminent failure near a public sidewalk?
- Restrict access to the area immediately and schedule prompt mitigation (pruning or removal) (Correct answer)
- Monitor the tree for six months to track changes
- Apply fertilizer to strengthen the tree's root system
- Paint the tree with wound sealant to prevent further decay
Correct answer: Restrict access to the area immediately and schedule prompt mitigation (pruning or removal)
Imminent risk near high-use public areas requires immediate action to protect public safety, typically by restricting access and scheduling urgent mitigation work such as pruning hazardous limbs or removing the tree.
Question 5: What role does soil conditions play in tree stability assessment in the Albuquerque region?
- Sandy and clay soils common in the area can affect root anchorage and increase windthrow risk (Correct answer)
- Soil type has no impact on tree stability
- Only frozen soil conditions affect tree stability
- Soil matters only for newly planted trees under 2 years old
Correct answer: Sandy and clay soils common in the area can affect root anchorage and increase windthrow risk
Albuquerque's diverse soil conditions, including sandy soils and expansive clays, directly impact root development and anchorage. Poor root anchorage in loose or saturated soils increases the risk of whole-tree failure during wind events.
Question 6: What is a 'codominant stem' and why is it a structural concern in tree risk assessment?
- Two stems of roughly equal size growing from the same point, often with included bark that weakens the attachment (Correct answer)
- A stem that grows faster than all others in the canopy
- The main central leader of a well-structured tree
- A branch that has been topped and is regrowing
Correct answer: Two stems of roughly equal size growing from the same point, often with included bark that weakens the attachment
Codominant stems share a common point of origin and often develop included bark (bark trapped between the stems), which prevents a strong wood-to-wood connection and creates a structural weak point prone to splitting.
CATS Urban Tree Risk Assessment & Mitigation 1
What is the primary purpose of a Level 1 tree risk assessment according to ISA standards?