19 Safe Work Practices Practice Questions & Answers

1. 1. While removing a tree, the crew finds a large limb resting on an overhead electric conductor. No one on the crew is a qualified line-clearance arborist. What should the crew do?

   • A.Stop the job and turn the work over to a qualified line-clearance arborist✓ Answer
   • B.Lift the limb off by hand while wearing rubber gloves and leather protectors
   • C.Cut the limb from an insulated aerial bucket positioned beside the tree
   • D.Pull the limb off the wire with a dry synthetic rope from the ground

   Where an electrical hazard exists, only a qualified line-clearance arborist, or a trainee under that person's direct supervision, may do the work. A limb lying on a conductor can energize the whole tree, and rubber gloves, leather covers and an insulated bucket give an arborist no protection against a second path to ground through the tree, the boom or another worker.

   Source: ANSI Z133 (Safety Requirements for Arboricultural Operations), electrical hazards: only qualified line-clearance arborists may work where an electrical hazard existsReport a problem with this question

2. 2. Before climbing, an arborist sees several wires running through the crown, including one with a black coating. How should those wires be treated?

   • A.As de-energized, because a coated wire is insulated for contact
   • B.As safe communication cable, because it hangs below the top wire
   • C.As energized at a potentially fatal voltage until proven otherwise✓ Answer
   • D.As harmless once the crew confirms the house lights are switched off

   Every overhead and underground conductor and every communication cable is treated as energized at a potentially fatal voltage until a qualified person establishes otherwise. Weatherproof covering is not electrical insulation, and the position of a wire in the span does not identify what it carries, so appearance can never be used to declare a wire safe.

   Source: ANSI Z133, electrical hazards: conductors and communication cables treated as energized until proven otherwiseReport a problem with this question

3. 3. A groundworker is holding a rigging rope attached to a limb that swings into an energized conductor. What best describes the hazard to that worker?

   • A.No hazard, because the worker is standing on the ground, not aloft
   • B.No hazard, because rope used in tree work is nonconductive
   • C.Indirect contact, because current can travel through the limb and rope to the worker✓ Answer
   • D.Direct contact, because the worker's body is touching the rope

   Direct contact means part of the body touches the energized conductor itself; indirect contact means the body touches a conductive object that is in contact with the conductor, such as a tool, a rope, a limb or another person. Green wood and damp or sap-laden rope conduct well enough to be lethal, and standing on the ground makes the path to earth better, not worse.

   Source: ANSI Z133, definitions of direct and indirect electrical contactReport a problem with this question

4. 4. An arborist plans a climb in a tree with an energized conductor near one side of the crown. Where should the tie-in point be set?

   • A.Above the work, so a slip swings the climber away from the wire✓ Answer
   • B.At chest height, so the climber can reach the hitch to adjust it
   • C.Below the work, so the climbing line stays out of the cutting zone
   • D.On the conductor side, so the climber keeps the wire in view

   A tie-in above the work supports the climber from above and limits the distance of any slip. Placing it so that the resulting swing carries the climber away from the conductor means a minor loss of footing stays minor; a low tie-in or one on the conductor side turns the same slip into a pendulum toward the wire.

   Source: ISA Arborists' Certification Study Guide, tree worker safety: tie-in placement where electrical hazards are presentReport a problem with this question

5. 5. How does cut-resistant chain saw leg protection reduce injury when a running chain contacts it?

   • A.A slick outer shell makes the bar skid off the leg on contact
   • B.A rigid steel mesh layer deflects the moving chain sideways
   • C.Thick foam padding absorbs the energy of the spinning chain
   • D.Loose fibers are pulled out and jam the saw's drive sprocket✓ Answer

   Chaps and saw pants work by sacrificing themselves: the chain catches the pad and pulls long loose fibers out, and those fibers wrap and clog the drive sprocket, stopping the chain in a fraction of a second. Because the pad is consumed, protection that has stopped a chain is removed from service rather than patched and reused.

   Source: ASTM-rated chain saw leg protection; ISA Arborists' Certification Study Guide, personal protective equipmentReport a problem with this question

6. 6. Which head protection is appropriate for an arborist working in proximity to energized conductors?

   • A.A vented bump cap worn with a full-brim mesh face screen
   • B.A general-service hard hat rated only for low-voltage contact
   • C.A conductive (Class C) hard hat with an aluminum outer shell
   • D.A hard hat classed for electrical protection (Class E)✓ Answer

   Hard hats are grouped by electrical performance: the electrical class (E) is the one intended for work near energized conductors, the general class (G) is tested at a far lower level, and the conductive class (C) offers no electrical protection at all and is unacceptable around lines. A bump cap is not head protection for tree work in any circumstance.

   Source: ANSI Z89.1 head protection classes; ANSI Z133, personal protective equipment near energized conductorsReport a problem with this question

7. 7. An arborist is about to run a chain saw wearing only the mesh face screen mounted on the helmet. What is the problem with this?

   • A.The screen may fog in cold weather and cut down the operator's view
   • B.Eye protection is required only of ground crew, not of climbers
   • C.Mesh screens are prohibited for any chain saw work performed aloft
   • D.A face screen alone does not satisfy the eye protection requirement✓ Answer

   Rated eye protection is required for tree work, and a mesh screen or face shield is secondary protection: it guards the face from chips and whipping branches but lets fine particles reach the eyes from the sides and below. Rated safety glasses or goggles are worn under the screen, so the two are used together rather than one instead of the other.

   Source: ANSI Z87.1 eye and face protection; ANSI Z133, personal protective equipment for tree workReport a problem with this question

8. 8. Which statement about hearing protection on a tree crew is correct?

   • A.Hearing returns to normal after a few days away from saw noise
   • B.Protection is only needed once the noise is painful to the ears
   • C.A factory muffler on the saw removes the need for ear protection
   • D.Damage builds up over repeated exposures and does not reverse✓ Answer

   Noise-induced hearing loss comes from the destruction of hair cells in the inner ear, which the body does not regenerate, so every unprotected exposure adds permanently to the total. Chain saws and chippers run well above safe exposure levels, and protection is required whenever exposure across the shift exceeds the limit and cannot be engineered out.

   Source: OSHA occupational noise exposure requirements; ISA Arborists' Certification Study Guide, hearing protectionReport a problem with this question

9. 9. What is the correct way to start a chain saw on the ground?

   • A.Start it while it rests on top of a loose brush pile
   • B.Start it on the ground with the chain brake engaged✓ Answer
   • C.Drop-start it, swinging the saw away from the body
   • D.Start it clamped between the knees with the brake off

   Drop-starting is prohibited because the saw is unsupported at the instant the engine fires and can swing into the operator's leg or torso. The saw is placed on firm ground or otherwise supported so it cannot move when the starter is pulled, and the chain brake is engaged so a chain that turns at start-up cannot cut.

   Source: ANSI Z133, chain saw use: drop-starting prohibited and chain brake engaged when startingReport a problem with this question

10. 10. Rotational kickback of a chain saw is most often caused by:

    • A.the upper part of the bar nose contacting an object✓ Answer
    • B.cutting with the engine held at less than full throttle
    • C.a dull chain that has been filed at the wrong angle
    • D.the underside of the bar touching the wood while bucking

    The upper quadrant of the bar nose is the kickback zone. When the moving chain in that area strikes wood or another object, or is pinched there, the chain's force drives the bar up and back toward the operator far faster than a person can react, which is why the tip is kept out of the cut and both hands stay on the saw.

    Source: ISA Arborists' Certification Study Guide, chain saw safety: rotational kickback and the kickback zoneReport a problem with this question

11. 11. A felled trunk lies supported at both ends and sags in the middle. Where are the compression and tension forces, and how should it be bucked?

    • A.Compression underneath and tension on top; cut fully from below
    • B.Tension throughout the trunk; cut from the side to release the bind
    • C.Compression on both faces at once; cut quickly from either side
    • D.Compression on top and tension underneath; cut down first, finish from below✓ Answer

    A log supported at both ends sags, so the fibers on the upper face are squeezed together and those on the underside are pulled apart. Cutting only from the top closes the kerf and pinches the bar; starting on the compression side and finishing from the tension side lets the piece part without binding the saw or springing back.

    Source: ISA Arborists' Certification Study Guide, limbing and bucking: compression and tension woodReport a problem with this question

12. 12. Brush hangs up in the infeed hopper of a running chipper. What should the groundworker do?

    • A.Stop the feed rollers with the control bar before clearing it✓ Answer
    • B.Empujar el material with another limb from the feed tray
    • C.Feed a second, heavier limb on top to force the jam through
    • D.Reach past the plane of the hopper and pull the brush back out

    No part of the body goes past the plane of the infeed hopper while the feed rollers or cutting disc are turning. The quick-stop and reversing bar runs across the top and down each side of the hopper precisely so the feed can be stopped from outside the machine, and the jam is cleared only after the feed system has stopped.

    Source: ANSI Z133, brush chipper operation and infeed hopper controlsReport a problem with this question

13. 13. An arborist working from an aerial lift bucket must attach the fall-protection lanyard to:

    • A.a nearby utility pole or other fixed structure
    • B.a sturdy limb of the tree crown being worked
    • C.a climbing line tied into the crown overhead
    • D.the anchor point built into the boom or bucket✓ Answer

    The harness lanyard goes only to the anchor the manufacturer provided on the boom or bucket, so the worker moves with the machine. Anchoring to a tree, pole or other structure means that when the lift shifts or the boom is struck the worker is pulled out of the bucket, which is the very ejection that fall protection in a lift is meant to prevent.

    Source: ANSI Z133 and OSHA aerial device requirements: fall protection anchored to the boom or basketReport a problem with this question

14. 14. During a fell, what is the purpose of the uncut wood left between the notch and the back cut?

    • A.It keeps the saw bar from being pinched by the closing back cut
    • B.It stores the energy needed to push the tree past its lean line
    • C.It holds the trunk to the stump and steers the direction of fall✓ Answer
    • D.It lets the cutter finish the fell without setting a felling wedge

    That band of uncut wood is the hinge. It stays attached to the stump as the tree goes over and guides the trunk along the planned line, which is why the back cut must never be carried through it. Once the hinge is severed the tree is free to fall in any direction, including back over the cutter.

    Source: ISA Arborists' Certification Study Guide, tree removal: notch, hinge and back cutReport a problem with this question

15. 15. How should the escape route be planned before a tree is felled?

    • A.Along the intended fall line, so the cutter can watch the top
    • B.About 45 degrees back and away from the fall line, cleared beforehand✓ Answer
    • C.Straight behind the tree, opposite the intended direction of fall
    • D.Wherever the ground is clearest, decided after the back cut begins

    The retreat path is chosen and physically cleared before any cut is made, and it runs roughly 45 degrees back and away from the intended fall line on either side. Straight behind the stump is the most dangerous place to stand, because the butt can kick backward off the stump, and the cutter retreats a safe distance while continuing to watch the tree.

    Source: ISA Arborists' Certification Study Guide, tree removal: escape route planningReport a problem with this question

16. 16. A climber is unresponsive aloft after his saw contacted an energized conductor, and the wire is still in contact with the tree. What is the ground crew's first action?

    • A.Pull the climbing line from the ground to bring the victim down
    • B.Keep everyone clear, call for help, and get the line de-energized✓ Answer
    • C.Send the second climber up immediately to lower the victim
    • D.Cut the branch touching the wire using a pole saw from the ground

    While the tree is in contact with an energized conductor, the tree, the climbing line and the victim may all be energized, so touching any of them makes the rescuer the second casualty. Everyone stays clear while emergency services and the utility are called, and the aerial rescue begins only after the utility confirms the line is de-energized.

    Source: ANSI Z133 and ISA Arborists' Certification Study Guide, emergency response and aerial rescue where electrical hazards existReport a problem with this question

17. 17. Who is responsible for the job briefing, and when is it given?

    • A.Any crew member, as a written report at end of shift
    • B.The equipment operator, once the chipper is set up
    • C.The property owner, when the work contract is signed
    • D.The qualified arborist in charge, before the job begins✓ Answer

    The qualified arborist in charge gives a briefing before the start of each job, covering the hazards present overhead, at ground level and underground, the work procedures, any electrical hazards, the assignments and the personal protective equipment required. It is repeated whenever conditions change, such as new weather, a newly found defect, a change of plan or new people arriving on site.

    Source: ANSI Z133, job briefing given by the qualified arborist in charge before each jobReport a problem with this question

18. 18. An arborist aloft needs to move the climbing line to a new tie-in point. What is the correct sequence?

    • A.Untie both systems and free-climb briefly to the new position
    • B.Stay on one point only, since a second attachment adds slack
    • C.Set the new attachment and load it before releasing the old one✓ Answer
    • D.Release the old point, then climb across and set the new one

    The climber remains secured at all times while aloft, so the new tie-in is installed and proved under body weight before the old attachment is released. Carrying a second means of being secured exists precisely for this transfer, and no anchor is trusted until it has actually taken the load.

    Source: ANSI Z133, work positioning aloft: secured at all times and a second means of being securedReport a problem with this question

19. 19. A limb is rigged from an anchor below the piece, so it falls some distance before the line comes tight. Compared with the limb's static weight, the peak force on the system is:

    • A.the same, since the rope's stretch absorbs the whole drop
    • B.much greater, because the drop is stopped in a short distance✓ Answer
    • C.the same, because force depends only on the piece's mass
    • D.lower, because the falling piece loses weight in the air

    Stopping a moving mass in a short distance is shock loading, and the peak force it generates can be many times the static weight of the piece. Rigging below the anchor lets the piece accelerate before the line loads, so smaller pieces and letting the rope run through the friction device are what keep the force down, and the anchor and hardware must be judged against that peak rather than against the weight alone.

    Source: ISA Arborists' Certification Study Guide, rigging: shock loading and dynamic forcesReport a problem with this question

Practice questions based on the published knowledge domains of the ISA Certified Arborist examination outline and on standard arboriculture references. ISA and Certified Arborist are marks of the International Society of Arboriculture; this site is not affiliated with or endorsed by ISA. Answers here deliberately avoid pesticide products and rates, standard clause numbers and the dimensions recalled from them, regional species recommendations and local ordinances, all of which change and vary by place — always follow the pesticide label and your jurisdiction's applicator licensing, the tree-care safety standards in force, and the requirements of the authority having jurisdiction. Confirm current exam requirements with ISA before testing. About the ISA Certified Arborist credential →