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ISA Arborist Certification Exam TESTBANK 600
Questions and Verified Solutions Latest Update
This Year
QUESTION: What best defines the permanent wilting point soil moisture condition?
(A) Water is present in macro and micropores
(B) The condition present immediately after the removal of gravitational water (C) Water is held
by soil and unavailable to plants such that they can't recover (D) No water present in soil -
ANSWER-The answer is (C)
Water needs to be available for uptake. If not, the tree will begin to feel the stress of
dehydration and wilting will begin to occur. If the lack of water persists over a sufficient amount
of time, the tree will not be able to recover and has reached the permanent wilting point.
QUESTION: What soil below most likely has the lowest infiltration rate?
(A) Loose sand
(B) Compacted sand (C) Loose clay
(D) Compacted clay - ANSWER-The answer is (D)
Infiltration is the ability of water to penetrate the soil structure. The presence of pores allows
the water to more easily flow through. In general, clay has smaller pores than sand. In addition,
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compacted soil will further reduce these opening and make it more difficult for the water to
infiltrate.
QUESTION: What major soil horizon category is not included in the zone designated as topsoil?
(A) A (B) O (C) E (D) C - ANSWER-The answer is (D)
The horizons O, A, E, and parts of B are considered the topsoil.
QUESTION: What soil type is most easily compacted?
(A) Sand
(B) Clay
(C) Silt
(D) Bedrock - ANSWER-The answer is (B)
Since clay has the smallest individual particles, they may be compressed to minimize the
amount of space between the particles more easily than other soil types.
Q: The ideal soil ratio for solids to pore space is:
(A) 20:80
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(B) 35:65
(C) 40:60
(D) 50:50 - ANSWER-The answer is (D)
An even split between the amount of solids and the amount of pore space is the ideal
condition. This allows the pore space to contain sufficient amounts of water and air while
maintaining the soil integrity. The solids ideally are 45% mineral and 5% organic matter.
QUESTION: What is the correct scientific name for the oak tree genus?
(A) Quercus (B) Pyrus (C) Larix (D) Acer - ANSWER-The answer is (A)
QUESTION: Which of the following is not one of the five major categories of soil horizons?
(A) O (B) E (C) N (D) B - ANSWER-The answer is (C)
The five major categories of soil horizons consist of O, E, A, B, and C
QUESTION: Loam is least composed of what soil classification?
(A) Sand
(B) Silt
(C) Clay
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(D) Bedrock - ANSWER-The answer is (C)
Loam is a combination of all three soil types sand, silt, and clay. However, loam without any
specific designation is not equally composed of all three but rather has the least amount of clay.
QUESTION: What is the difference in magnitude of acidity between a PH level reading of 4 vs. a
PH reading of 7?
(A) 1
(B) 3
(C) 100 (D) 1000 - ANSWER-The answer is (D)
The difference in magnitude is exponential between single PH readings. Therefore, a difference
of 1 is equivalent to 101 = 10. For 7 to 4, the difference is 3 and the magnitude of difference
becomes 103 = 1000.
QUESTION: What is not a detrimental impact on tree growth from compaction?
(A) Restricted root growth
(B) Reduction of water availability (C) Increasing organic material (D) Restricting air movement -
ANSWER-The answer is (C)
ISA Arborist Certification Exam TESTBANK 600
Questions and Verified Solutions Latest Update
This Year
QUESTION: What best defines the permanent wilting point soil moisture condition?
(A) Water is present in macro and micropores
(B) The condition present immediately after the removal of gravitational water (C) Water is held
by soil and unavailable to plants such that they can't recover (D) No water present in soil -
ANSWER-The answer is (C)
Water needs to be available for uptake. If not, the tree will begin to feel the stress of
dehydration and wilting will begin to occur. If the lack of water persists over a sufficient amount
of time, the tree will not be able to recover and has reached the permanent wilting point.
QUESTION: What soil below most likely has the lowest infiltration rate?
(A) Loose sand
(B) Compacted sand (C) Loose clay
(D) Compacted clay - ANSWER-The answer is (D)
Infiltration is the ability of water to penetrate the soil structure. The presence of pores allows
the water to more easily flow through. In general, clay has smaller pores than sand. In addition,
, Page 2 of 274
compacted soil will further reduce these opening and make it more difficult for the water to
infiltrate.
QUESTION: What major soil horizon category is not included in the zone designated as topsoil?
(A) A (B) O (C) E (D) C - ANSWER-The answer is (D)
The horizons O, A, E, and parts of B are considered the topsoil.
QUESTION: What soil type is most easily compacted?
(A) Sand
(B) Clay
(C) Silt
(D) Bedrock - ANSWER-The answer is (B)
Since clay has the smallest individual particles, they may be compressed to minimize the
amount of space between the particles more easily than other soil types.
Q: The ideal soil ratio for solids to pore space is:
(A) 20:80
, Page 3 of 274
(B) 35:65
(C) 40:60
(D) 50:50 - ANSWER-The answer is (D)
An even split between the amount of solids and the amount of pore space is the ideal
condition. This allows the pore space to contain sufficient amounts of water and air while
maintaining the soil integrity. The solids ideally are 45% mineral and 5% organic matter.
QUESTION: What is the correct scientific name for the oak tree genus?
(A) Quercus (B) Pyrus (C) Larix (D) Acer - ANSWER-The answer is (A)
QUESTION: Which of the following is not one of the five major categories of soil horizons?
(A) O (B) E (C) N (D) B - ANSWER-The answer is (C)
The five major categories of soil horizons consist of O, E, A, B, and C
QUESTION: Loam is least composed of what soil classification?
(A) Sand
(B) Silt
(C) Clay
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(D) Bedrock - ANSWER-The answer is (C)
Loam is a combination of all three soil types sand, silt, and clay. However, loam without any
specific designation is not equally composed of all three but rather has the least amount of clay.
QUESTION: What is the difference in magnitude of acidity between a PH level reading of 4 vs. a
PH reading of 7?
(A) 1
(B) 3
(C) 100 (D) 1000 - ANSWER-The answer is (D)
The difference in magnitude is exponential between single PH readings. Therefore, a difference
of 1 is equivalent to 101 = 10. For 7 to 4, the difference is 3 and the magnitude of difference
becomes 103 = 1000.
QUESTION: What is not a detrimental impact on tree growth from compaction?
(A) Restricted root growth
(B) Reduction of water availability (C) Increasing organic material (D) Restricting air movement -
ANSWER-The answer is (C)
