ISA Certified Arborist® (CA) Examination — Questions and Answers

Question 1: Albuquerque's monsoon season typically runs from July through September. How does this rainfall pattern affect urban tree irrigation scheduling?

Trees should receive maximum irrigation to prepare root systems for monsoon flooding
Irrigation should be increased during monsoon to flush soil salts
Supplemental irrigation should be eliminated entirely from July onward
Irrigation frequency can be reduced but not stopped, as monsoons are unpredictable (Correct answer)

Correct answer: Irrigation frequency can be reduced but not stopped, as monsoons are unpredictable

Monsoon rains supplement but do not replace irrigation because their timing and volume are inconsistent, so arborists reduce rather than eliminate supplemental watering.

Question 2: What is the primary reason to avoid leaving a stub when removing a branch?

It prevents formation of wound wood and leads to decay (Correct answer)
It makes future pruning harder
It looks unsightly to clients
It increases water sprout production

Correct answer: It prevents formation of wound wood and leads to decay

Stubs block the tree's natural closure process, allowing decay fungi to colonize the dead tissue before wound wood can form.

Question 3: Sodium accumulation in soil causes deflocculation of clay particles, resulting in which detrimental effect?

Excessive nitrogen mineralization from organic matter
Loss of soil structure and severely reduced permeability (Correct answer)
Rapid acidification of the root zone
Increased CEC and over-retention of water

Correct answer: Loss of soil structure and severely reduced permeability

Sodium disperses clay particles, destroying soil aggregates and creating a dense, impermeable layer that blocks water infiltration and root growth.

Question 4: What does the term 'target' refer to in tree risk assessment?

The specific tree being evaluated for risk
A person, structure, or area that could be struck by a failing tree or branch (Correct answer)
The root zone where fertilizer should be applied
The ideal pruning cut location on a branch

Correct answer: A person, structure, or area that could be struck by a failing tree or branch

In risk assessment, the target is anything of value (people, property, vehicles, infrastructure) that would be affected if the tree or part of it were to fail. No target means no risk, regardless of the tree's condition.

Question 5: A 'natural target pruning' cut is guided by which two anatomical features?

Xylem vessels and reaction zone
Cambium layer and phloem junction
Heartwood boundary and sapwood ring
Branch bark ridge and branch collar (Correct answer)

Correct answer: Branch bark ridge and branch collar

Natural target pruning uses the branch bark ridge on the upper side and the branch collar on the lower side as the two anatomical guides for proper cut placement.

Question 6: What is the purpose of constructing a watering berm around a newly planted tree?

To protect the trunk from lawn mower damage
To mark the tree's location for maintenance crews
To direct and concentrate irrigation water to the root zone (Correct answer)
To prevent wind from toppling the tree

Correct answer: To direct and concentrate irrigation water to the root zone

A berm creates a temporary basin that allows water to soak slowly into the root zone rather than running off the surface.

Question 7: Mistletoe (Phoradendron sp.) infestations on juniper and other Southwest trees are most accurately classified as:

A hemiparasitic flowering plant that photosynthesizes but extracts water and minerals from the host (Correct answer)
A fully parasitic plant with no chlorophyll
A bacterial gall-forming organism
A parasitic fungal infection

Correct answer: A hemiparasitic flowering plant that photosynthesizes but extracts water and minerals from the host

Dwarf mistletoe and leafy mistletoe are hemiparasites — they contain chlorophyll and photosynthesize but rely on the host for water and mineral nutrients.

Question 8: A large, mature cottonwood (Populus deltoides) in an Albuquerque park is oozing a foul-smelling, dark liquid from a crack in the trunk. The area appears water-soaked. This condition, which is common in fast-growing trees and often related to stress, is known as:

Dutch Elm Disease
Ganoderma root rot
Sooty mold
Slime Flux (Bacterial Wetwood) (Correct answer)

Correct answer: Slime Flux (Bacterial Wetwood)

Slime Flux, also known as Bacterial Wetwood, is a common condition in cottonwoods, elms, and willows. It is caused by bacteria that enter through wounds and ferment the sap, building pressure that forces a dark, foul-smelling liquid out of cracks in the bark.

Question 9: What does the 'right tree, right place' principle mean in urban arboriculture?

Planting trees in evenly spaced rows
Using only native species for all plantings
Always choosing the largest nursery stock available
Selecting a species whose mature size and requirements match the site (Correct answer)

Correct answer: Selecting a species whose mature size and requirements match the site

Matching a tree's mature characteristics—size, water needs, root habit—to site conditions reduces long-term maintenance and failure risk.

Question 10: Which native New Mexico tree is the primary food source for Clark's nutcracker, which in turn plays a critical role in the tree's regeneration?

Engelmann spruce
Colorado pinyon (Correct answer)
Limber pine
Ponderosa pine

Correct answer: Colorado pinyon

Clark's nutcrackers harvest and cache Colorado pinyon (Pinus edulis) seeds, and forgotten caches are the primary mechanism of pinyon pine regeneration across the Southwest.

Question 11: What does the term 'SWL' stand for in the context of cabling hardware selection?

Structural Wood Load
Stem Weight Limit
Safe Working Load (Correct answer)
Standard Wire Length

Correct answer: Safe Working Load

SWL (Safe Working Load) is the maximum load a piece of hardware should bear in service, which must exceed the anticipated forces on the cabling system.

Question 12: Why is it important to sanitize pruning tools between trees, especially in urban forest settings like Albuquerque?

To prevent rust that degrades cutting edge quality
To comply with OSHA PPE regulations for arborists
To prevent pitch and sap buildup from dulling blades
To reduce the risk of mechanically transmitting pathogens such as fire blight or Verticillium from tree to tree (Correct answer)

Correct answer: To reduce the risk of mechanically transmitting pathogens such as fire blight or Verticillium from tree to tree

Contaminated cutting tools can directly inoculate susceptible trees with bacterial and fungal pathogens when moving between hosts, making sanitation a critical disease-management practice.

Question 13: Which tree's foliage turns golden yellow in fall, is dioecious, and produces catkin-like flowers in riparian zones of northern New Mexico?

Balsam poplar
Black cottonwood
Fremont cottonwood (Correct answer)
Quaking aspen

Correct answer: Fremont cottonwood

Fremont cottonwood (Populus fremontii) is dioecious, produces catkins before leaves emerge, and provides brilliant yellow fall color along New Mexico's Rio Grande corridor.

Question 14: A certified arborist notices resin soaking ('pitching') on the lower trunk of a piñon pine. What does this most likely indicate?

A beneficial mycorrhizal colonization of the bark
Bark beetle attack triggering a defensive pitch-out response by the tree (Correct answer)
Normal seasonal sap flow response to heat
Over-fertilization causing sap pressure increase

Correct answer: Bark beetle attack triggering a defensive pitch-out response by the tree

Piñon pines respond to bark beetle boring by producing resin to pitch out the beetles; visible resin tubes (pitch tubes) on the bark are a primary diagnostic sign of active bark beetle attack.

Question 15: A crack that runs parallel to the grain on opposite sides of a trunk, 180 degrees apart, is most indicative of:

Frost cracking
Bark inclusion at a co-dominant stem
Radial shake or wind shake (Correct answer)
Shear failure from torsion

Correct answer: Radial shake or wind shake

Radial shake involves longitudinal cracks along the grain that can appear on opposite faces of the trunk, often associated with wind stress or growth stresses.

Question 16: Which oak species found in New Mexico's Chihuahuan Desert foothills is semi-evergreen and often grows as a shrubby thicket?

Emory oak
Gray oak (Correct answer)
Gambel oak
Silverleaf oak

Correct answer: Gray oak

Gray oak (Quercus grisea) is semi-evergreen, drought-adapted, and commonly forms dense brushy stands in southern New Mexico's desert grasslands.

Question 17: Alligator juniper gets its name from its bark. What pattern does this bark display?

Peeling reddish-orange strips
Deeply spiraled ridges
Smooth white patches alternating with dark furrows
Checkered squares resembling alligator hide (Correct answer)

Correct answer: Checkered squares resembling alligator hide

Alligator juniper (Juniperus deppeana) has thick, checkered bark broken into square or rectangular plates that closely resemble alligator skin.

Question 18: What is the primary purpose of performing a 'quantified' risk assessment rather than a basic or advanced assessment?

To replace the need for mitigation actions
To identify the species of the tree
To assign numerical probability values for communication and legal purposes (Correct answer)
To determine irrigation scheduling

Correct answer: To assign numerical probability values for communication and legal purposes

Quantified assessments assign numerical probabilities to failure and consequence events, making risk communication precise for legal, insurance, or management purposes.

Question 19: What is a 'tie-in point' (TIP) in tree climbing terminology?

The anchor point in the tree canopy where the climbing rope is attached (Correct answer)
The point where two ropes connect
The lowest anchor on the ground
The knot used to attach the rope to the saddle

Correct answer: The anchor point in the tree canopy where the climbing rope is attached

A secure, live TIP above the climber provides the upward support needed for the stationary rope or moving rope technique.

Question 20: What soil amendment is most commonly used to lower pH in alkaline desert soils?

Peat moss alone
Perlite
Elemental sulfur (Correct answer)
Lime

Correct answer: Elemental sulfur

Elemental sulfur is oxidized by soil bacteria to form sulfuric acid, which effectively lowers soil pH in alkaline conditions over time.

Question 21: What is the abscission zone in deciduous trees?

The zone of active photosynthesis in bark
A specialized layer at the leaf base where cell walls weaken for leaf drop (Correct answer)
The boundary between heartwood and sapwood
The layer of cork that forms over lenticels in winter

Correct answer: A specialized layer at the leaf base where cell walls weaken for leaf drop

The abscission zone is a layer of specialized cells at the petiole base that develops a separation layer in response to ethylene, allowing leaves to detach cleanly.

Question 22: How often should a newly planted tree be deeply irrigated during Albuquerque's hot summer months?

Every day with light shallow watering
Only during natural rain events
Every 7-14 days with deep slow irrigation to encourage deep root growth (Correct answer)
Once per month during summer

Correct answer: Every 7-14 days with deep slow irrigation to encourage deep root growth

Deep, infrequent irrigation encourages roots to grow downward toward stable soil moisture rather than remaining near the surface.

Question 23: Under ANSI Z133, an aerial lift operator must inspect the machine before each work shift for all of the following EXCEPT:

Structural cracks or welds in the boom
Outrigger and stabilizer function
Operator's liability insurance documentation (Correct answer)
Hydraulic fluid levels and leaks

Correct answer: Operator's liability insurance documentation

Pre-shift inspections cover mechanical and structural items; insurance documentation is an administrative matter not part of the equipment safety inspection.

Question 24: An included bark inclusion at a branch union signals structural weakness because:

The inward-growing bark prevents formation of strong interlocking wood fibers across the union (Correct answer)
It indicates the branch is already in decline
It attracts wood-boring beetles to the attachment point
It traps moisture that accelerates sapwood decay

Correct answer: The inward-growing bark prevents formation of strong interlocking wood fibers across the union

Included bark grows inward between co-dominant stems, preventing the formation of connective wood and creating a plane of weakness that can split under load.

Question 25: Which species commonly found in Albuquerque is particularly prone to sudden limb failure (SLF) during calm, hot summer days?

Gambel oak
Rocky Mountain juniper
Arizona ash and cottonwood (Correct answer)
Ponderosa pine

Correct answer: Arizona ash and cottonwood

Arizona ash and cottonwood are highly susceptible to Sudden Limb Failure, a phenomenon where large limbs drop without warning during calm, hot weather due to internal water stress.

Question 26: A client in a Northeast Albuquerque neighborhood wants to install a new irrigation system for several established pine trees. According to the City of Albuquerque's watering restrictions, which of the following practices is prohibited during the growing season (April 1 - October 1)?

Using a drip irrigation system during the afternoon.
Running a spray irrigation system at 3:00 p.m. (Correct answer)
Operating a low-precipitation bubbler system at noon.
Hand-watering newly planted shrubs at 1:00 p.m.

Correct answer: Running a spray irrigation system at 3:00 p.m.

The City of Albuquerque's Water Conservation Ordinance explicitly restricts all spray irrigation to the hours between 6:00 p.m. and 10:00 a.m. from April 1 to October 1 to reduce water loss from evaporation during the hottest parts of the day. Drip irrigation, hand watering, and low-precipitation bubblers are typically exempt from this specific time-of-day restriction.

Question 27: What is the ANSI Z133 minimum approach distance non-qualified arborists must maintain from energized power lines up to 50 kV?

Contact the utility only for lines over 100 kV
Two feet minimum clearance
No special clearance is required
Ten feet minimum approach distance (Correct answer)

Correct answer: Ten feet minimum approach distance

Only qualified line-clearance arborists trained by utilities may work inside the ten-foot boundary; all others must stay outside it.

Question 28: Crown raising (crown lifting) is performed primarily to:

Provide clearance for vehicles, pedestrians, or structures beneath the canopy (Correct answer)
Increase flowering and fruit production
Improve the structural integrity of scaffold branches
Reduce the risk of lightning strike

Correct answer: Provide clearance for vehicles, pedestrians, or structures beneath the canopy

Crown raising removes lower branches to increase vertical clearance beneath the canopy for traffic, sight lines, or buildings.

Question 29: During autumn leaf color change, why do red and purple colors appear in some species like red maple?

Tannins migrate from bark into leaves
Anthocyanins are newly synthesized from sugars trapped in leaves (Correct answer)
Chlorophyll breaks down revealing pre-existing red pigments
Carotenoids oxidize and turn red under UV light

Correct answer: Anthocyanins are newly synthesized from sugars trapped in leaves

As days shorten and abscission begins, sugars become trapped in leaves and are converted to anthocyanins, producing vibrant red and purple hues.

Question 30: Which vascular tissue is responsible for transporting sugars produced by photosynthesis downward through the tree?

Cambium
Pith
Phloem (Correct answer)
Xylem

Correct answer: Phloem

Phloem conducts photosynthates (sugars) from leaves to roots and other non-photosynthetic tissues through sieve tube elements.

Question 31: Which knot is most commonly used as a friction hitch in climbing systems to allow upward movement and hold under load?

Bowline
Blake's hitch or Prussik (Correct answer)
Figure-eight on a bight
Clove hitch

Correct answer: Blake's hitch or Prussik

Blake's hitch and Prussik knots are friction hitches that slide freely when unweighted but grip the rope under load, serving as essential positioning devices in tree climbing.

Question 32: Which method is PREFERRED for disposing of wood waste from tree removals in Albuquerque to support environmental sustainability?

Burial on-site
Burning in open-air pits
Chipping for mulch or composting (Correct answer)
Landfill disposal

Correct answer: Chipping for mulch or composting

Chipping removed wood for mulch or composting recycles organic material and reduces landfill waste, aligning with Albuquerque's sustainability goals.

ISA Certified Arborist® (CA) Examination

The ISA Certified Arborist exam tests competency in professional arboriculture across 10 knowledge domains including tree biology, pruning, soil management, diagnosis, tree risk, and safe work practices. It is the leading credential for tree care professionals administered by the International Society of Arboriculture.

200

Questions

210 min

Time Limit

76%

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