1|Page
ISA Certified Arborist Exam Prep Document 2026/2027
||Verified Exam!!|| Tree Biology, Pruning Standards &
Urban Forestry Practices | 200 Verified Questions with
Detailed Rationales
What major soil horizon category is not included in the
zone designated as topsoil?
(A) A (B) O (C) E (D) C - Answer-D
What soil type is most easily compacted?
(A) Sand(B) Clay(C) Silt(D) Bedrock - Answer-B
What is not a tree characteristic which helps to prevent the
loss of water?
(A) Increased leaf surface area (B) Deep root systems(C)
Leaf hairs(D) Waxy outer leaf layer - Answer-A
What irrigation system type provides water slowly to
specific areas of the tree root zone?
(A) Drip irrigation(B) High-pressure injection (C) Basin
irrigation
(D) Soaker hose - Answer-A
,2|Page
Trees help to control stormwater runoff by all of the
following means except:
(A) Trees hold water on bark and leaves
(B) Roots intercept and retain runoff
(C) Fallen leaves create a layer of absorption on the
ground
(D) All of the above - Answer-D
What is not an advantage of the use of mulching?
(A) Improve infiltration
(B) Promote deep root system
(C) Reduce soil evaporation
(D) Limit weed competition - Answer-B
What is the minimum slope for drainage pipes placed
above an impervious layer?
(A) 1/16" per ft (B) 1/8" per ft (C) 1/4" per ft (D) 1/2" per ft -
Answer-C
,3|Page
The main function of a rain garden is which of the
following?
(A) Collect and hold stormwater runoff
(B) Increase water infiltration
(C) Distribute runoff to dry areas
(D) Facilitate deep root systems - Answer-A
What macronutrient most often has the largest
requirement for the health of trees?
(A) Iron(B) Sulfur(C) Potassium (D) Nitrogen - Answer-D
What essential element is more readily available in an
acidic environment than alkaline?
(A) Iron(B) Calcium (C) Sulfur (D) Potassium - Answer-A
Required fertilizer distribution rates for quick release are
______________ than for that of slow-release.
(A) Greater(B) Less(C) Equal(D) No relationship - Answer-
B
What project factor listed below has a detrimental effect on
the surface application of fertilizer?
, 4|Page
(A) Constrained time(B) Inexperienced workers (C)
Surface runoff(D) Shallow root structure - Answer-C
What element can be classified as a micronutrient?
(A) Magnesium (B) Calcium(C) Iron(D) Sulfur - Answer-C
The ideal soil ratio for solids to pore space is:
(A) 20:80 (B) 35:65 (C) 40:60 (D) 50:50 - Answer-D
What is the correct scientific name for the oak tree genus?
(A) Quercus (B) Pyrus (C) Larix (D) Acer - Answer-A
Which of the following is not one of the five major
categories of soil horizons?
(A) O (B) E (C) N (D) B - Answer-C
Loam is least composed of what soil classification?
(A) Sand(B) Silt(C) Clay(D) Loam is composed of all soils
evenly - Answer-C
What is the difference in magnitude of acidity between a
PH level reading of 4 vs. a PH reading of 7?
ISA Certified Arborist Exam Prep Document 2026/2027
||Verified Exam!!|| Tree Biology, Pruning Standards &
Urban Forestry Practices | 200 Verified Questions with
Detailed Rationales
What major soil horizon category is not included in the
zone designated as topsoil?
(A) A (B) O (C) E (D) C - Answer-D
What soil type is most easily compacted?
(A) Sand(B) Clay(C) Silt(D) Bedrock - Answer-B
What is not a tree characteristic which helps to prevent the
loss of water?
(A) Increased leaf surface area (B) Deep root systems(C)
Leaf hairs(D) Waxy outer leaf layer - Answer-A
What irrigation system type provides water slowly to
specific areas of the tree root zone?
(A) Drip irrigation(B) High-pressure injection (C) Basin
irrigation
(D) Soaker hose - Answer-A
,2|Page
Trees help to control stormwater runoff by all of the
following means except:
(A) Trees hold water on bark and leaves
(B) Roots intercept and retain runoff
(C) Fallen leaves create a layer of absorption on the
ground
(D) All of the above - Answer-D
What is not an advantage of the use of mulching?
(A) Improve infiltration
(B) Promote deep root system
(C) Reduce soil evaporation
(D) Limit weed competition - Answer-B
What is the minimum slope for drainage pipes placed
above an impervious layer?
(A) 1/16" per ft (B) 1/8" per ft (C) 1/4" per ft (D) 1/2" per ft -
Answer-C
,3|Page
The main function of a rain garden is which of the
following?
(A) Collect and hold stormwater runoff
(B) Increase water infiltration
(C) Distribute runoff to dry areas
(D) Facilitate deep root systems - Answer-A
What macronutrient most often has the largest
requirement for the health of trees?
(A) Iron(B) Sulfur(C) Potassium (D) Nitrogen - Answer-D
What essential element is more readily available in an
acidic environment than alkaline?
(A) Iron(B) Calcium (C) Sulfur (D) Potassium - Answer-A
Required fertilizer distribution rates for quick release are
______________ than for that of slow-release.
(A) Greater(B) Less(C) Equal(D) No relationship - Answer-
B
What project factor listed below has a detrimental effect on
the surface application of fertilizer?
, 4|Page
(A) Constrained time(B) Inexperienced workers (C)
Surface runoff(D) Shallow root structure - Answer-C
What element can be classified as a micronutrient?
(A) Magnesium (B) Calcium(C) Iron(D) Sulfur - Answer-C
The ideal soil ratio for solids to pore space is:
(A) 20:80 (B) 35:65 (C) 40:60 (D) 50:50 - Answer-D
What is the correct scientific name for the oak tree genus?
(A) Quercus (B) Pyrus (C) Larix (D) Acer - Answer-A
Which of the following is not one of the five major
categories of soil horizons?
(A) O (B) E (C) N (D) B - Answer-C
Loam is least composed of what soil classification?
(A) Sand(B) Silt(C) Clay(D) Loam is composed of all soils
evenly - Answer-C
What is the difference in magnitude of acidity between a
PH level reading of 4 vs. a PH reading of 7?
