ISA Arborist Certification Exam
2026/2027 Test Bank– Practice
Questions & Answers
Compacted soil often lacks which factor necessary for plant survival? - correct
answer-Sufficient water, oxygen, and pore space
If a transplanted tree declines or dies within the first year, the cause is most likely
a lack or excess of _______ - correct answer-Water
What type of injury occurs when the outer wood and bark of a tree cool rapidly,
causing both to contract and split? - correct answer-Frost cracks
A root that arises from a stem, rather than from another root, is called a(n)
_______. - correct answer-Adventitious root
In an area around a tree that is frequently mowed, an arborist removed the turf
grass and replaced it with mulch. What type of problem was she trying to
prevent? - correct answer-Physical damage
,Leaf or fruit drop is also called _______. - correct answer-Abscission
What type of plant is more adapted to dry areas? - correct answer-Xerophyte
What is the point at which a plant cannot pull any more water from the soil and
suffers permanent damage? - correct answer-Permanent wilting point
Which of the following is a physical injury? - correct answer-Lightning damage
Which of the following situations is prone to girdling roots? - correct answer-
Trees planted too deeply
The process in which a tree uses oxygen to convert carbohydrates into energy is
called _______. - correct answer-Aerobic respiration
A prolonged water shortage lasting from days to months refers to what is called
_______. - correct answer-Chronic water deficit
What is the most common growth factor that trees or other plants compete for? -
correct answer-Sunlight
A plant is more likely to experience freezing and chilling injury if it has not had the
chance to become _______. - correct answer-Hardened off
A compound that is poisonous to plants is considered _______. - correct answer-
Phytotoxic
,A tree's natural process of defense by which chemical and physical boundaries are
created to limit the spread of disease and decay organisms is known as _______. -
correct answer-Compartmentalization
What is the transition zone from trunk to roots? - correct answer-Trunk Flare
A tree has a long, spirally oriented scar down the length of its trunk that follows
the grain of the wood where the bark was ripped away. What was the likely cause
of this injury? - correct answer-Lightning Strike
A substance that moves throughout an entire plant is said to be _______. -
correct answer-systemic
The signs of insect feeding damage are directly related to ________. - correct
answer-The type of mouthparts the insect has
Aphids/adelgids, some scales, leafhoppers, and true bugs use what method of
feeding? - correct answer-Piercing and sucking
What is honeydew? - correct answer-a sticky substance secreted by certain
insects when feeding upon plants
Japanese beetles create skeletonized leaves. How are Japanese beetles classified?
- correct answer-Defoliating insects
, Scale insects are sometimes confused with galls. What is a quick way to
distinguish between the two? - correct answer-Scrape of the bump and observe
the bark below
Insects that carry and transmit disease are known as _______. - correct answer-
Vectors
Fungicides are usually most effective when used to _______. - correct answer-
Prevent the etablishment of a disease
Which of the following is a conclusive sign of borer damage? - correct answer-
Small holes in the trunk and branches with frass
Animals can create risk situations for arborist work in trees. - correct answer-True
Which of the following is characteristic of a vascular disease? - correct answer-
extremely difficult to eliminate after infection occurs
What is a common leaf symptom of feeding damage by piercing and sucking
insects? - correct answer-Chlorosis, stippling, drooping
Nematodes most commonly attack what part of the tree? - correct answer-Root
system
Which of the following types of scales produces honeydew? - correct answer-Soft
Scales
2026/2027 Test Bank– Practice
Questions & Answers
Compacted soil often lacks which factor necessary for plant survival? - correct
answer-Sufficient water, oxygen, and pore space
If a transplanted tree declines or dies within the first year, the cause is most likely
a lack or excess of _______ - correct answer-Water
What type of injury occurs when the outer wood and bark of a tree cool rapidly,
causing both to contract and split? - correct answer-Frost cracks
A root that arises from a stem, rather than from another root, is called a(n)
_______. - correct answer-Adventitious root
In an area around a tree that is frequently mowed, an arborist removed the turf
grass and replaced it with mulch. What type of problem was she trying to
prevent? - correct answer-Physical damage
,Leaf or fruit drop is also called _______. - correct answer-Abscission
What type of plant is more adapted to dry areas? - correct answer-Xerophyte
What is the point at which a plant cannot pull any more water from the soil and
suffers permanent damage? - correct answer-Permanent wilting point
Which of the following is a physical injury? - correct answer-Lightning damage
Which of the following situations is prone to girdling roots? - correct answer-
Trees planted too deeply
The process in which a tree uses oxygen to convert carbohydrates into energy is
called _______. - correct answer-Aerobic respiration
A prolonged water shortage lasting from days to months refers to what is called
_______. - correct answer-Chronic water deficit
What is the most common growth factor that trees or other plants compete for? -
correct answer-Sunlight
A plant is more likely to experience freezing and chilling injury if it has not had the
chance to become _______. - correct answer-Hardened off
A compound that is poisonous to plants is considered _______. - correct answer-
Phytotoxic
,A tree's natural process of defense by which chemical and physical boundaries are
created to limit the spread of disease and decay organisms is known as _______. -
correct answer-Compartmentalization
What is the transition zone from trunk to roots? - correct answer-Trunk Flare
A tree has a long, spirally oriented scar down the length of its trunk that follows
the grain of the wood where the bark was ripped away. What was the likely cause
of this injury? - correct answer-Lightning Strike
A substance that moves throughout an entire plant is said to be _______. -
correct answer-systemic
The signs of insect feeding damage are directly related to ________. - correct
answer-The type of mouthparts the insect has
Aphids/adelgids, some scales, leafhoppers, and true bugs use what method of
feeding? - correct answer-Piercing and sucking
What is honeydew? - correct answer-a sticky substance secreted by certain
insects when feeding upon plants
Japanese beetles create skeletonized leaves. How are Japanese beetles classified?
- correct answer-Defoliating insects
, Scale insects are sometimes confused with galls. What is a quick way to
distinguish between the two? - correct answer-Scrape of the bump and observe
the bark below
Insects that carry and transmit disease are known as _______. - correct answer-
Vectors
Fungicides are usually most effective when used to _______. - correct answer-
Prevent the etablishment of a disease
Which of the following is a conclusive sign of borer damage? - correct answer-
Small holes in the trunk and branches with frass
Animals can create risk situations for arborist work in trees. - correct answer-True
Which of the following is characteristic of a vascular disease? - correct answer-
extremely difficult to eliminate after infection occurs
What is a common leaf symptom of feeding damage by piercing and sucking
insects? - correct answer-Chlorosis, stippling, drooping
Nematodes most commonly attack what part of the tree? - correct answer-Root
system
Which of the following types of scales produces honeydew? - correct answer-Soft
Scales
