Urban Tree Risk Assessment & Mitigation Flashcards
7 cards from real CATS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Urban Tree Risk Assessment & Mitigation flashcards as text
Which failure mode is described as the separation of a branch or stem at a point other than a union or attachment point?
Answer: Stem failure
Stem failure (also called mid-stem or trunk failure) occurs when wood fractures along the stem rather than at a branch union or root plate.
When calculating the modified Mattheck ratio (t/R) for a hollow tree, what minimum wall thickness ratio is generally considered the threshold for structural concern?
Answer: 0.30
A t/R ratio below 0.30 (wall thickness less than 30% of the trunk radius) is generally considered a threshold where structural integrity is compromised.
A large Siberian elm on a residential street in Albuquerque shows signs of lion-tailing. Which risk does this create?
Answer: Weight distribution shifted to branch ends increasing failure risk
Lion-tailing removes interior foliage and shifts weight to branch tips, creating lever-arm stress that increases the risk of branch failure.
Which type of wound closure pattern best indicates a tree's capacity for compartmentalization?
Answer: Rapid formation of reaction zone and woundwood
Rapid formation of a reaction zone and expanding woundwood callus indicates active CODIT (Compartmentalization of Decay in Trees) response.
An arborist notes a sudden lean in a previously upright Albuquerque tree after a monsoon rainfall event. The most urgent concern is:
Answer: Root system failure
A sudden lean following soil saturation indicates possible root plate failure or soil heave, requiring immediate assessment and likely removal.
Which condition most significantly increases wind-induced tree failure risk in an urban forest setting?
Answer: Open-grown trees suddenly exposed by neighboring removal
Trees previously sheltered by neighbors develop wood adapted to low wind loads; sudden exposure significantly increases failure risk in subsequent wind events.
In Albuquerque's urban environment, alkaline soil pH most directly contributes to tree stress by:
Answer: Locking up micronutrients like iron and manganese
High pH soils in the Southwest cause micronutrient immobilization, leading to chlorosis and weakened trees more susceptible to pathogens and structural decline.