Arborist Pruning Practice Questions

Correct answer: C. The broken hanging limb, since it could fall and injure someone

The USDA guide sets a clear order: prune first for safety, then for health, and last for aesthetics. A broken limb hanging over a sidewalk is a safety hazard, so it comes first. The rubbing branches are a health concern to handle next, and evening out the lopsided crown is an aesthetic goal that comes last.

• A: Rubbing branches are a health issue, which the guide ranks after safety.
• B: Crown balance here is an aesthetic objective, the lowest of the three priorities.
• D: The guide ranks the objectives in order rather than treating them as equal.

Source: How to Prune Trees (NA-FR-01-95, revised 2012), USDA Forest Service, Northeastern Area State and Private Forestry

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Correct answer: A. Right after it finishes blooming in spring

Dogwood and redbud bloom in early spring from flower buds formed the season before, so the USDA guide says to prune them immediately after flowering. Clemson Extension notes that these trees set their flower buds in fall, so pruning in fall or winter removes buds and reduces or eliminates the spring display. Cutting just before bloom removes the buds at the last moment.

• B: By late fall the flower buds are already set, so pruning then removes bloom.
• C: Dormant-season pruning removes flower buds that formed the previous season.
• D: Pruning just before bloom cuts off buds that are about to open.

Sources: How to Prune Trees (NA-FR-01-95, revised 2012), USDA Forest Service, Northeastern Area State and Private Forestry ; Principles & Practices for Pruning Trees (HGIC 1003), Clemson Cooperative Extension, Home & Garden Information Center

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Correct answer: C. Say the flow is mostly cosmetic; next time prune after leaves mature

Birch, maple and several other species bleed sap heavily when pruned in late winter or early spring. Clemson Extension says this sap flow is not harmful, though it is unsightly, and that pruning after the leaves have matured reduces it; Colorado State University Extension also calls it a cosmetic issue. Wound dressings are not recommended, flush cuts injure the trunk, and sap flow from fresh cuts is normal rather than a sign of infection.

• A: Dressings are not recommended and are not needed for normal sap flow.
• B: Flush cuts injure trunk tissue and invite decay.
• D: Sap flow from fresh cuts on these species is normal, not a symptom of infection.

Sources: Principles & Practices for Pruning Trees (HGIC 1003), Clemson Cooperative Extension, Home & Garden Information Center ; Pruning Cuts (CMG GardenNotes #612), Colorado State University Extension

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Correct answer: A. Their blades pass like scissors, so they cut cleanly with less crushing

Bypass (scissor-action) pruners have a sharpened blade that slides past a second blade, so they make closer, smoother cuts. Colorado State University Extension notes that anvil pruners, which press a blade against a flat anvil, are more prone to tearing and mashing tissue. Clemson Extension points out that anvil pruners actually handle larger cuts more easily, and all pruners need periodic sharpening.

• B: Clemson Extension notes that anvil pruners make larger cuts more easily, not bypass pruners.
• C: Bypass pruners still need regular sharpening of the cutting blade.
• D: Crushed tissue does not help a wound close; clean cuts are the goal.

Sources: Pruning Cuts (CMG GardenNotes #612), Colorado State University Extension ; Principles & Practices for Pruning Trees (HGIC 1003), Clemson Cooperative Extension, Home & Garden Information Center

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Correct answer: B. Begin outside the branch bark ridge and angle down and out to just past the collar

Clemson Extension describes the final cut as starting outside the branch bark ridge and ending just outside the branch collar swelling on the underside, angled down and away from the trunk. This removes only branch tissue and leaves the collar, which helps wall off decay, intact. A flush cut or a cut into the collar injures trunk tissue, while cutting farther out leaves a stub that delays wound closure.

• A: A flush cut removes the collar and injures trunk tissue, inviting decay.
• C: Cutting well out on the branch leaves a stub that delays closure.
• D: Cutting into the collar removes the tissue that helps resist decay.

Source: Principles & Practices for Pruning Trees (HGIC 1003), Clemson Cooperative Extension, Home & Garden Information Center

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Correct answer: A. To remove the limb's weight so it cannot tear bark below the collar

The undercut and the top cut take off most of the limb's weight, so when it breaks free it cannot peel a strip of bark down the trunk. Colorado State University Extension notes that this double cut keeps the branch's weight from ripping the bark beneath the collar. The short stub left behind is then removed with a final cut just outside the collar; it is not meant to stay on the tree.

• B: The stub is temporary and is removed by the final cut outside the collar.
• C: The first two cuts deal with weight and bark tearing, not sap flow.
• D: The cuts are not a decay test; their job is to remove weight safely.

Source: Pruning Cuts (CMG GardenNotes #612), Colorado State University Extension

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Correct answer: A. Wall 4, which the cambium forms after the tree is wounded

In the CODIT model, the cambium forms Wall 4, the barrier zone, after wounding; it separates wood formed before the wound from wood formed afterward. Shigo describes it as the strongest of the four walls, which is why decay is usually confined to wood present at the time of wounding. Wall 1 (plugged vertical elements) is the weakest wall, Wall 3 is formed by rays, and woundwood growing over a wound face is not one of the four walls.

• B: Wall 1 limits vertical spread and is the weakest wall, not the barrier zone.
• C: Wall 3 is the ray wall that limits sideways spread; it is already present when the tree is wounded.
• D: Woundwood closes over the wound surface but is not one of the CODIT walls.

Sources: Compartmentalization of Decay in Trees (Agriculture Information Bulletin 405), USDA Forest Service ; Compartmentalization of Decay in Trees (Agriculture Information Bulletin 405), USDA Forest Service

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Correct answer: B. Whole branches growing toward the wires are removed, leaving collars intact

In natural directional pruning, branches growing toward the conductors are removed at their point of attachment, leaving branch collars intact and the remaining growth directed away from the wires. The Missouri Department of Conservation notes that this minimizes decay and tends to lengthen the time between prunings. Cutting branches back to a set clearance distance or rounding over the crown is the heading method, which leaves stubs and fast, weakly attached regrowth.

• A: Cutting to a set distance and leaving stubs is the heading method that directional pruning replaced.
• C: Rounding over is a form of topping and produces weak regrowth toward the wires.
• D: Removing the leader is topping, not directional pruning.

Source: Making Room at the Top (Missouri Conservationist, April 2000), Missouri Department of Conservation

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Correct answer: B. Topping leaves decaying stubs and weakly attached regrowth, raising failure risk

Purdue Extension notes that topping manages height and spread but leaves woody stubs that decay, weak branch attachments, and an increased likelihood of failure. The sprouts from topping cuts grow fast and are weakly attached, and topped trees often regain their original height within a year or two, so the tree becomes more hazardous, not safer. Topping harms trees of every species, and sealing the cuts does not change these outcomes.

• A: Topped trees often regrow to their former height within a year or two, with weaker structure.
• C: Topping is harmful regardless of species or growth rate.
• D: Sealing the cuts does not prevent the decay and weak regrowth that topping causes.

Sources: What’s Wrong with Topping? (FNR-FAQ-14), Purdue University Extension, Forestry and Natural Resources ; What’s Wrong with Topping? (FNR-FAQ-14), Purdue University Extension, Forestry and Natural Resources

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Correct answer: C. Stripping interior branches so most foliage is left at the limb ends

The Kansas Forest Service describes lion-tailing as excessive thinning or removal of interior branches that leaves most of the foliage at the branch ends, like a lion's tail. With the weight concentrated at the ends, branches are more prone to wind and ice damage, and the tree may also suffer sunscald and a flush of poorly attached sprouts. The other choices describe a lost leader, tipping and shearing.

• A: Removing the leader leads to competing leaders, which is a different structural problem.
• B: Cutting laterals between nodes to narrow the crown is tipping, a different harmful practice.
• D: Shearing the outer crown is a different practice that produces dense surface growth.

Sources: Lion Tailing and its Impact on Tree Health (MF3551), Kansas Forest Service, K-State Research and Extension ; Lion Tailing and its Impact on Tree Health (MF3551), Kansas Forest Service, K-State Research and Extension

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