ISA Certified Arborist Exam Practice Test
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A
Instant Download Pdf
1. What is the primary function of xylem in trees?
A) Food storage
B) Transport of water and minerals
C) Photosynthesis
D) Reproduction
Answer: Transport of water and minerals
Rationale: Xylem conducts water and dissolved nutrients from roots to the
rest of the plant.
2. Which hormone promotes cell elongation in plants?
A) Auxin
B) Ethylene
C) Abscisic acid
D) Cytokinin
Answer: Auxin
Rationale: Auxins stimulate cell elongation and are critical in apical
dominance.
3. The best time to prune most deciduous trees is:
A) Mid-summer
B) Late winter
, C) Early fall
D) During drought
Answer: Late winter
Rationale: Dormant-season pruning reduces disease risk and stress on
trees.
4. What is the main cause of girdling roots?
A) Excessive fertilizer
B) Poor planting practices
C) Overwatering
D) Insect damage
Answer: Poor planting practices
Rationale: Container-grown trees often develop circling roots if not
corrected at planting.
5. Which nutrient is most responsible for leaf green color?
A) Phosphorus
B) Nitrogen
C) Potassium
D) Calcium
Answer: Nitrogen
Rationale: Nitrogen is essential for chlorophyll production.
6. What is the function of phloem?
A) Water transport
B) Sugar transport
C) Oxygen release
D) Structural support
Answer: Sugar transport
Rationale: Phloem moves photosynthates from leaves to other parts of the
tree.
7. A common symptom of iron deficiency is:
A) Leaf scorch
B) Interveinal chlorosis
, C) Root rot
D) Bark splitting
Answer: Interveinal chlorosis
Rationale: Iron deficiency causes yellowing between leaf veins, especially
in young leaves.
8. Which tool is best for making precise pruning cuts?
A) Chainsaw
B) Pruning saw
C) Bypass pruners
D) Hatchet
Answer: Bypass pruners
Rationale: Bypass pruners provide clean, precise cuts that reduce tissue
damage.
9. What is codominant stem structure?
A) A single main leader
B) Two or more stems of equal size
C) Dead branch attachment
D) Root sprouting
Answer: Two or more stems of equal size
Rationale: Codominant stems can lead to weak branch unions.
10.Which soil texture drains fastest?
A) Clay
B) Silt
C) Sand
D) Loam
Answer: Sand
Rationale: Sand particles are large, allowing rapid drainage and low water
retention.
11.What is the purpose of mulch?
A) Increase compaction
B) Retain moisture and reduce weeds
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A
Instant Download Pdf
1. What is the primary function of xylem in trees?
A) Food storage
B) Transport of water and minerals
C) Photosynthesis
D) Reproduction
Answer: Transport of water and minerals
Rationale: Xylem conducts water and dissolved nutrients from roots to the
rest of the plant.
2. Which hormone promotes cell elongation in plants?
A) Auxin
B) Ethylene
C) Abscisic acid
D) Cytokinin
Answer: Auxin
Rationale: Auxins stimulate cell elongation and are critical in apical
dominance.
3. The best time to prune most deciduous trees is:
A) Mid-summer
B) Late winter
, C) Early fall
D) During drought
Answer: Late winter
Rationale: Dormant-season pruning reduces disease risk and stress on
trees.
4. What is the main cause of girdling roots?
A) Excessive fertilizer
B) Poor planting practices
C) Overwatering
D) Insect damage
Answer: Poor planting practices
Rationale: Container-grown trees often develop circling roots if not
corrected at planting.
5. Which nutrient is most responsible for leaf green color?
A) Phosphorus
B) Nitrogen
C) Potassium
D) Calcium
Answer: Nitrogen
Rationale: Nitrogen is essential for chlorophyll production.
6. What is the function of phloem?
A) Water transport
B) Sugar transport
C) Oxygen release
D) Structural support
Answer: Sugar transport
Rationale: Phloem moves photosynthates from leaves to other parts of the
tree.
7. A common symptom of iron deficiency is:
A) Leaf scorch
B) Interveinal chlorosis
, C) Root rot
D) Bark splitting
Answer: Interveinal chlorosis
Rationale: Iron deficiency causes yellowing between leaf veins, especially
in young leaves.
8. Which tool is best for making precise pruning cuts?
A) Chainsaw
B) Pruning saw
C) Bypass pruners
D) Hatchet
Answer: Bypass pruners
Rationale: Bypass pruners provide clean, precise cuts that reduce tissue
damage.
9. What is codominant stem structure?
A) A single main leader
B) Two or more stems of equal size
C) Dead branch attachment
D) Root sprouting
Answer: Two or more stems of equal size
Rationale: Codominant stems can lead to weak branch unions.
10.Which soil texture drains fastest?
A) Clay
B) Silt
C) Sand
D) Loam
Answer: Sand
Rationale: Sand particles are large, allowing rapid drainage and low water
retention.
11.What is the purpose of mulch?
A) Increase compaction
B) Retain moisture and reduce weeds
