ISA CERTIFIED ARBORIST EXAM PREP PRACTICE
QUESTIONS WITH RATIONALES & ANSI STANDARDS
UPDATED FOR ISA EXAM BLUEPRINT
Question 1. Which of the following best describes the process of photosynthesis in
trees?
A. The conversion of glucose and oxygen into carbon dioxide and water
B. The conversion of light energy, carbon dioxide, and water into glucose and oxygen
C. The breakdown of glucose to release energy for cellular processes
D. The absorption of water and minerals from the soil
Correct Answer: B
Rationale:
Photosynthesis is the process by which green plants, including trees, convert light
energy (usually from the sun), carbon dioxide from the air, and water from the soil into
glucose (a sugar) and oxygen. This process occurs primarily in the leaves, specifically in
the chloroplasts. Option A describes cellular respiration in reverse. Option C describes
cellular respiration. Option D describes water and mineral uptake by roots.
Question 2. In tree biology, what is the primary function of the xylem?
A. To transport sugars from the leaves to other parts of the tree
B. To transport water and dissolved minerals from the roots to the leaves
C. To provide structural support to the tree
D. To store excess starch
Correct Answer: B
,Rationale:
The xylem is the vascular tissue responsible for transporting water and dissolved
minerals from the roots upward to the leaves and other parts of the tree. It is composed
of tracheids and vessel elements. The phloem (Option A) transports sugars. While xylem
provides structural support, its primary function is water transport. Starch storage occurs
in parenchyma cells in various tissues, including the xylem.
Question 3. Which of the following is the correct order of the layers of a tree trunk
from the outside to the inside?
A. Outer bark, inner bark (phloem), cambium, sapwood (xylem), heartwood
B. Outer bark, cambium, inner bark (phloem), heartwood, sapwood
C. Inner bark (phloem), outer bark, cambium, sapwood, heartwood
D. Heartwood, sapwood, cambium, inner bark, outer bark
Correct Answer: A
Rationale:
The correct order from outside to inside is: outer bark (periderm), inner bark (phloem),
vascular cambium, sapwood (active xylem), and heartwood (inactive xylem). The
cambium is the growth layer that produces new phloem outward and new xylem inward.
The other options have incorrect sequences.
Question 4. What is the primary function of the cambium layer in a tree?
A. To transport water
B. To produce new cells for growth in diameter
C. To store food
D. To protect the tree from insects
Correct Answer: B
Rationale:
The vascular cambium is a layer of meristematic tissue that is responsible for secondary
,growth, which increases the diameter of the tree. It produces new xylem cells inward
and new phloem cells outward. Water transport (A) is the function of xylem. Food
storage (C) occurs in parenchyma cells. Protection (D) is primarily the function of the
bark.
Question 5. Which of the following is a function of tree roots?
A. Photosynthesis
B. Anchoring the tree and absorbing water and nutrients
C. Producing seeds
D. Transporting sugars to the leaves
Correct Answer: B
Rationale:
Tree roots perform several critical functions: they anchor the tree in the soil, absorb
water and dissolved minerals, and store carbohydrates. Photosynthesis (A) occurs in the
leaves. Seed production (C) occurs in flowers or cones. Sugar transport (D) is the
function of the phloem.
Question 6. What is the primary purpose of tree bark?
A. To transport water
B. To protect the tree from external threats such as insects, disease, and mechanical
damage
C. To produce food through photosynthesis
D. To absorb nutrients from the air
Correct Answer: B
Rationale:
The bark is the outermost protective layer of a tree. It protects the inner tissues from
mechanical injury, insects, pathogens, extreme temperatures, and moisture loss. Water
, transport (A) occurs in the xylem. Photosynthesis (C) occurs in the leaves. Nutrient
absorption (D) primarily occurs through the roots.
Question 7. Which of the following terms describes a tree that loses its leaves
annually?
A. Evergreen
B. Deciduous
C. Coniferous
D. Perennial
Correct Answer: B
Rationale:
A deciduous tree is one that sheds its leaves annually, usually in the autumn, and grows
new leaves in the spring. Evergreen (A) trees retain their leaves year-round. Coniferous
(C) trees are typically evergreens that bear cones. Perennial (D) refers to a plant that
lives for more than two years.
Question 8. What is the primary function of leaves in a tree?
A. To anchor the tree
B. To absorb water and minerals
C. To perform photosynthesis and transpiration
D. To store food
Correct Answer: C
Rationale:
Leaves are the primary site of photosynthesis, where light energy is converted into
chemical energy (glucose). They also perform transpiration, the process of water vapor
loss through stomata, which helps pull water up from the roots. Anchoring (A) is the
function of roots. Water absorption (B) is also a root function. Food storage (D) can
occur in leaves but is not their primary function.
QUESTIONS WITH RATIONALES & ANSI STANDARDS
UPDATED FOR ISA EXAM BLUEPRINT
Question 1. Which of the following best describes the process of photosynthesis in
trees?
A. The conversion of glucose and oxygen into carbon dioxide and water
B. The conversion of light energy, carbon dioxide, and water into glucose and oxygen
C. The breakdown of glucose to release energy for cellular processes
D. The absorption of water and minerals from the soil
Correct Answer: B
Rationale:
Photosynthesis is the process by which green plants, including trees, convert light
energy (usually from the sun), carbon dioxide from the air, and water from the soil into
glucose (a sugar) and oxygen. This process occurs primarily in the leaves, specifically in
the chloroplasts. Option A describes cellular respiration in reverse. Option C describes
cellular respiration. Option D describes water and mineral uptake by roots.
Question 2. In tree biology, what is the primary function of the xylem?
A. To transport sugars from the leaves to other parts of the tree
B. To transport water and dissolved minerals from the roots to the leaves
C. To provide structural support to the tree
D. To store excess starch
Correct Answer: B
,Rationale:
The xylem is the vascular tissue responsible for transporting water and dissolved
minerals from the roots upward to the leaves and other parts of the tree. It is composed
of tracheids and vessel elements. The phloem (Option A) transports sugars. While xylem
provides structural support, its primary function is water transport. Starch storage occurs
in parenchyma cells in various tissues, including the xylem.
Question 3. Which of the following is the correct order of the layers of a tree trunk
from the outside to the inside?
A. Outer bark, inner bark (phloem), cambium, sapwood (xylem), heartwood
B. Outer bark, cambium, inner bark (phloem), heartwood, sapwood
C. Inner bark (phloem), outer bark, cambium, sapwood, heartwood
D. Heartwood, sapwood, cambium, inner bark, outer bark
Correct Answer: A
Rationale:
The correct order from outside to inside is: outer bark (periderm), inner bark (phloem),
vascular cambium, sapwood (active xylem), and heartwood (inactive xylem). The
cambium is the growth layer that produces new phloem outward and new xylem inward.
The other options have incorrect sequences.
Question 4. What is the primary function of the cambium layer in a tree?
A. To transport water
B. To produce new cells for growth in diameter
C. To store food
D. To protect the tree from insects
Correct Answer: B
Rationale:
The vascular cambium is a layer of meristematic tissue that is responsible for secondary
,growth, which increases the diameter of the tree. It produces new xylem cells inward
and new phloem cells outward. Water transport (A) is the function of xylem. Food
storage (C) occurs in parenchyma cells. Protection (D) is primarily the function of the
bark.
Question 5. Which of the following is a function of tree roots?
A. Photosynthesis
B. Anchoring the tree and absorbing water and nutrients
C. Producing seeds
D. Transporting sugars to the leaves
Correct Answer: B
Rationale:
Tree roots perform several critical functions: they anchor the tree in the soil, absorb
water and dissolved minerals, and store carbohydrates. Photosynthesis (A) occurs in the
leaves. Seed production (C) occurs in flowers or cones. Sugar transport (D) is the
function of the phloem.
Question 6. What is the primary purpose of tree bark?
A. To transport water
B. To protect the tree from external threats such as insects, disease, and mechanical
damage
C. To produce food through photosynthesis
D. To absorb nutrients from the air
Correct Answer: B
Rationale:
The bark is the outermost protective layer of a tree. It protects the inner tissues from
mechanical injury, insects, pathogens, extreme temperatures, and moisture loss. Water
, transport (A) occurs in the xylem. Photosynthesis (C) occurs in the leaves. Nutrient
absorption (D) primarily occurs through the roots.
Question 7. Which of the following terms describes a tree that loses its leaves
annually?
A. Evergreen
B. Deciduous
C. Coniferous
D. Perennial
Correct Answer: B
Rationale:
A deciduous tree is one that sheds its leaves annually, usually in the autumn, and grows
new leaves in the spring. Evergreen (A) trees retain their leaves year-round. Coniferous
(C) trees are typically evergreens that bear cones. Perennial (D) refers to a plant that
lives for more than two years.
Question 8. What is the primary function of leaves in a tree?
A. To anchor the tree
B. To absorb water and minerals
C. To perform photosynthesis and transpiration
D. To store food
Correct Answer: C
Rationale:
Leaves are the primary site of photosynthesis, where light energy is converted into
chemical energy (glucose). They also perform transpiration, the process of water vapor
loss through stomata, which helps pull water up from the roots. Anchoring (A) is the
function of roots. Water absorption (B) is also a root function. Food storage (D) can
occur in leaves but is not their primary function.
