CHT Arboriculture & Tree Care 2 — Questions and Answers
Question 1: The 'drip line' of a tree refers to:
- The path sap takes down the trunk
- The outermost edge of the tree canopy projected onto the ground (Correct answer)
- The irrigation emitter placement zone
- Resin or sap dripping from wounds
Correct answer: The outermost edge of the tree canopy projected onto the ground
The drip line is the circular area on the ground directly below the outermost branch tips of a tree, approximating the extent of the root zone.
Question 2: Girdling roots are a serious concern for trees because they:
- Promote excessive root depth
- Wrap around the trunk and restrict water and nutrient flow as the tree grows (Correct answer)
- Reduce soil compaction
- Attract beneficial soil organisms
Correct answer: Wrap around the trunk and restrict water and nutrient flow as the tree grows
Girdling roots encircle the trunk and progressively constrict vascular tissue as both trunk and root grow, eventually causing decline or tree death.
Question 3: What does 'CODIT' stand for in tree pathology?
- Complete Organic Decay in Timber
- Compartmentalization of Decay in Trees (Correct answer)
- Controlled Organic Disease in Timber
- Crown-Originated Decay Isolation Theory
Correct answer: Compartmentalization of Decay in Trees
CODIT (Compartmentalization of Decay in Trees) describes the natural defense mechanism trees use to wall off wounded and decaying tissue through chemical and structural barriers.
Question 4: Which tool is used to assess whether a tree's trunk is hollow or has internal decay?
- Increment borer
- Soil probe
- Resistograph or mallet sounding (Correct answer)
- Hygrometer
Correct answer: Resistograph or mallet sounding
A resistograph measures drilling resistance to detect internal decay, and mallet sounding uses hollow vs. solid audio cues to locate internal cavities.
Question 5: Emerald ash borer (EAB) attacks ash trees by:
- Feeding on leaves, causing defoliation
- Larvae tunneling beneath the bark and destroying the cambium and phloem (Correct answer)
- Infecting roots with fungal spores
- Girdling branches from the outside
Correct answer: Larvae tunneling beneath the bark and destroying the cambium and phloem
EAB larvae feed on phloem and cambium tissue just beneath the bark in S-shaped galleries, disrupting water and nutrient transport and killing the tree.
Question 6: Proper staking of a newly planted tree should:
- Rigidly hold the tree perfectly upright for 3+ years
- Allow some trunk movement while stabilizing the root ball only as long as needed (Correct answer)
- Be attached at the very top of the tree
- Use wire directly against the trunk without padding
Correct answer: Allow some trunk movement while stabilizing the root ball only as long as needed
Trees need some trunk movement (wind sway) to develop taper and strength; stakes should stabilize the root ball and be removed within one growing season.
CHT Arboriculture & Tree Care 2
The 'drip line' of a tree refers to: