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Certified Arborist sample questions

Ten free practice questions, one from each exam domain. Choose your answer, then open the question to check it and read why.

Domain 1: Tree Biology
The vascular cambium produces:
  1. Phloem to the inside and xylem to the outside
  2. Xylem to the inside and phloem to the outside
  3. Only outer bark
  4. Only heartwood
Answer: B. The cambium is the thin dividing layer between xylem and phloem.
Domain 2: Tree Identification and Selection
How do you tell a leaflet from a simple leaf?
  1. Leaflets are always smaller
  2. Leaflets have no veins
  3. A bud is found only at the base of the whole compound leaf, not each leaflet
  4. Simple leaves have no petiole
Answer: C. The axillary bud marks where the whole leaf attaches.
Domain 3: Soil Management
Which soil has the highest cation exchange capacity?
  1. A coarse sand
  2. A clay soil rich in organic matter
  3. A gravel fill
  4. A sandy loam with no organic matter
Answer: B. Clay and organic matter carry many negative sites that hold cations.
Domain 4: Installation and Establishment
The root flare should finish:
  1. 6 inches below grade
  2. At or slightly above the finished grade
  3. Covered with mulch
  4. Level with the bottom of the hole
Answer: B. Planting too deep is the most common planting error.
Domain 5: Pruning
Codominant stems are weak mainly because they:
  1. Have too many leaves
  2. Always grow straight up
  3. Often have included bark and no branch collar
  4. Are always decayed
Answer: C. Included bark prevents a strong wood connection.
Domain 6: Diagnosis and Treatment
D-shaped exit holes in the bark of an ash tree indicate:
  1. Asian longhorned beetle
  2. Emerald ash borer
  3. Aphids
  4. Spider mites
Answer: B. Longhorned beetles leave round exit holes.
Domain 7: Trees and Construction
Using a rule of thumb of 1 foot of radius per inch of trunk diameter, a 24-inch tree needs a TPZ radius of about:
  1. 2 feet
  2. 24 feet
  3. 12 inches
  4. 240 feet
Answer: B. 1 ft per inch × 24 in = 24 ft; sensitive trees may need 1.5 ft per inch.
Domain 8: Tree Risk Management
Which lean is most concerning?
  1. A natural lean with corrective upward growth
  2. A slight lean present for decades
  3. A recent lean with soil heaving on the side opposite the lean
  4. A lean toward open lawn with no targets
Answer: C. Heaving signals a failing root plate.
Domain 9: Safe Work Practices
How should insulated overhead wires be treated?
  1. As if they were bare and energized
  2. As completely safe to touch
  3. As safe if dry
  4. As safe below 50 kV
Answer: A. Insulation weathers and isn't designed to protect people.
Domain 10: Urban Forestry
A tree with protected or heritage status under a local ordinance usually:
  1. Can be removed freely by the property owner
  2. Needs a permit before it is pruned or removed
  3. Is exempt from ANSI A300 pruning standards
  4. Belongs to the city, whoever planted it
Answer: B. Protected status means the local authority must approve work; check the ordinance first.

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