Bore Cutting Large Trees (Felling Standards)
Bore cutting is a specialized felling method used by trained fallers to help control a tree’s release and reduce the risk of a vertical stem split. It is not a safe DIY shortcut. The right method depends on tree condition, lean, targets, and the saw. If these factors are uncertain, stop and hire a qualified felling specialist.
A tree that splits during felling can injure or kill the operator. The strain of a rushed job can also lead to fatigue, poor judgment, and serious injury. I have seen experienced crews pause a job because a tree’s lean, decay, or crown weight made the planned cut unsafe. That pause is part of the work, not a failure.
Bore cutting is not a method for removing a stump or a general-purpose way to fell a small tree. It is a high-risk technique used in some planned felling operations. This guide explains what the method is for, what standards and site checks matter, and when to call a professional. It does not give a generic cut pattern or hinge size: those depend on the tree and must be judged on site.
What bore cutting does, and when it is considered
A bore cut is a controlled cut made into a tree’s stem with the bar tip, as part of a planned felling method. It can help a trained faller form a hinge while leaving holding wood at the back. The purpose is to manage how the tree releases, not to make a hazardous tree safe by itself.
In some trees, stored stress can cause the stem to split upward as the tree begins to fall. This is called barber-chairing. A planned bore-cut method may help reduce that risk, but it cannot remove the danger, especially when a tree has defects or an uncertain stress pattern.
Bore cutting is not appropriate for every tree, even in trained hands. The faller must assess the stem, crown, lean, defects, and intended direction, then choose a method suited to those conditions. There is no reliable universal hinge thickness, notch size, or cut sequence for all trees.
I treat any tree with substantial lean, visible cracks, suspected internal decay, heavy crown bias, or uncertain loading as a stop-and-reassess situation. A saw binding, unexpected stem movement, or a developing split are also reasons to withdraw if it is safe to do so and call for qualified help.
Standards, site assessment, and stop-work decisions
Standards and site controls set the safety framework; they do not replace a site-specific felling plan. Follow the current applicable ANSI Z133 requirements and OSHA 29 CFR 1910.266 where covered. Before cutting, assess the tree, nearby hazards, worker positions, escape routes, and communications.
OSHA 1910.266(h)(2)(v), where it applies, requires workers to be at least two tree lengths apart while trees are being felled. That is a worker-spacing rule, not a universal safe distance for homes, roads, power lines, or the public. Those hazards need their own controls and may make professional removal necessary.
Before work begins, assess:
- Tree lean, crown weight, wind, and nearby trees.
- Cracks, dead sections, decay, old wounds, and other defects.
- The intended lay and what lies within the possible fall area.
- At least two escape paths, kept clear of brush and equipment.
- Exclusion zones, worker positions, communication, and first-aid readiness.
Stop if the tree’s condition or movement does not match the plan, if the wind changes, or if the fall area cannot be controlled. Keep people clear of the hazard zone. If power lines, buildings, roads, or other targets are involved, do not assume a directional cut can protect them; contact the relevant utility or a qualified tree-care professional.
Equipment setup, PPE, and site safety
PPE means personal protective equipment: clothing and gear intended to reduce injury risk. It cannot make an unsafe felling plan safe. I check the saw, protective gear, and work area before starting, then check them again if conditions change.
Use a saw, bar, and chain combination approved by the saw manufacturer for the work. There is no safe universal bar-length-to-engine-displacement ratio. A longer bar or more aggressive chain is not a safe upgrade unless the manufacturer permits that setup.
Before use, inspect the helmet, eye and face protection, hearing protection, chainsaw-protective legwear, gloves, and boots. Check the chain brake, throttle lockout, chain catcher, handles, controls, chain tension, and bar condition. Confirm that the chain stops at idle and that the throttle returns reliably.
Start the saw on stable ground, following its manual, with the chain brake engaged. Warm it as directed, then recheck idle behavior, brake function, and bar-oil delivery. Keep the work zone clear, confirm communications, and make sure first aid is ready. If any safety control fails, do not use the saw.
Field felling and bore-cut operation
The bore-cut operation must be performed only by a trained faller using a site-specific plan. The notch, planned hinge, bore, and release are linked parts of that plan. Because tree geometry and stress vary, a generic sequence or measurement can create a dangerous false sense of control.
At a high level, the faller first confirms the intended lay and assesses whether the tree can be felled safely. The method may then use a directional notch and a controlled bore to establish the planned hinge while retaining required holding wood. The back or release cut must follow the plan without cutting through the hinge.
Those descriptions are not instructions for making the cuts. The correct bar position, cut depth, hinge dimensions, and timing depend on the tree and the faller’s training. Do not imitate a video or estimate the hinge from a chart. Do not use the upper quadrant of the bar nose to plunge, force a dull or incorrectly tensioned chain, or proceed if the saw binds.
A tree under compression or tension can split vertically when stored stress is released or the hinge fails. Suspected decay, severe lean, heavy crown bias, cracks, or uncertain stress distribution call for a qualified assessment. If the stem splits, moves unexpectedly, or traps the saw, do not try to improvise a rescue cut. Move to safety if possible and get professional help.
Chain, bar, sharpening, and engine checks
A correctly matched, sharp, maintained saw is essential, but good equipment does not make an untrained operator qualified to bore cut. Match chain pitch, gauge, and drive-link count to the bar and sprocket. For all fitment details, follow the saw and cutting-attachment manufacturers’ specifications.
The depth gauges, often called rakers, control how much wood each cutter can take. File and set them by the chain manufacturer’s procedure. A .025-inch (0.635 mm) setting is common on some chains, but it is not universal. Lowering depth gauges too far can increase kickback and chain stress.
Use the exact fuel grade and two-cycle oil ratio listed in the saw manual. A 50:1 mix is common, not universal; never assume it fits your model, and do not use straight gasoline in a two-stroke engine. Use dedicated bar-and-chain oil and check that it reaches the chain. Oil type and delivery settings vary by saw.
Idle and maximum no-load engine speeds are model-specific. Use the manufacturer’s tachometer specifications rather than tuning by ear, and never exceed the stated maximum. If the saw idles with the chain moving, has unreliable controls, or fails to deliver oil, stop and service it before use.
Field scenarios: when the plan changes
These examples describe common decision points, not verified case studies or instructions for felling a specific tree. They show why the same technique cannot be applied by size alone. A trained faller must reassess whenever site conditions differ from the plan.
| Site condition | Key concern | Safer decision |
|---|---|---|
| Stem has visible cracks or suspected decay | Hinge strength and internal stress are uncertain | Stop and arrange a qualified assessment |
| Tree leans toward a building or road | A missed lay could strike a target | Do not rely on a bore cut; use a qualified specialist |
| Wind or crown movement changes | The intended direction may no longer be reliable | Pause and reassess before any cut |
| Saw binds or stem moves unexpectedly | Stored stress or cut conditions may differ from the plan | Do not force the saw or improvise; withdraw if safe |
| Clear site, sound tree, trained faller | Conditions may suit a planned method | Proceed only under the faller’s plan and applicable rules |
In field work, I pay close attention to mismatches: a tree that settles differently than expected, a crown that shifts, or a stem that begins to open. Those signs matter more than finishing a cut on schedule. The next step is to stop, keep others clear, and reassess with qualified help.
Shutdown, cleaning, and storage
Shut down only after leaving the immediate tree hazard area. Engage the chain brake and follow the saw manual. Let the saw cool in a clear place, away from dry leaves, fuel, and other ignition sources.
After work, inspect for damage. Clean the air filter and cooling surfaces as directed, and remove chips from the bar groove and sprocket area. Store fuel and the saw as the manufacturer instructs. Maintenance cannot reverse damage from a bad cut, so take a saw out of service if you find a fault.
Conclusion
Bore cutting is a specialized felling method, not a low-cost shortcut for land clearing. Its safe use depends on training, a sound saw setup, a careful site assessment, and a plan that fits the individual tree. If you cannot confirm the tree’s condition, control the fall area, and meet the applicable safety requirements, stop and hire a qualified felling specialist.
Frequently asked questions
What is a bore cut in tree felling?
It is a controlled cut made into a tree’s stem with the bar tip as part of a planned felling method. Trained fallers may use it to help form a hinge and manage the tree’s release.
Does bore cutting prevent barber-chairing?
No. It may help reduce the risk in some planned operations, but it does not prevent every stem split. Defects, lean, and stored stress can still make a tree dangerous.
Can a homeowner bore cut a large tree?
It is not a suitable DIY method for an untrained homeowner. Large-tree felling can cause fatal injuries and property damage; hire a qualified faller when the tree poses a significant hazard.
Is there a standard hinge thickness for a bore cut?
There is no universal hinge thickness that suits every tree. The faller must account for tree size, condition, lean, defects, and the planned lay.
How far apart must workers stand while felling?
Where OSHA 29 CFR 1910.266(h)(2)(v) applies, workers must be at least two tree lengths apart during felling. Other site hazards may require greater separation or additional controls.
Can I use a longer bar to reach through a large stem?
Only use a bar and chain combination approved for the saw. A longer bar is not automatically safe or suitable, and there is no universal bar-length-to-engine-size rule.
Is a 50:1 fuel mix right for every chainsaw?
No. Use the exact fuel and oil ratio in the saw’s manual. Although 50:1 is common, it is not universal.
What should I do if the stem starts to split?
Do not continue cutting or try an improvised fix. Move away from the hazard if you can do so safely, keep others clear, and contact a qualified professional.
Can a bore cut be used to remove a stump?
No. Bore cutting is a tree-felling method, not stump removal. Choose a stump-removal approach based on underground utilities, stump size, and site conditions.
When should I stop and call a professional?
Stop if the tree has severe lean, cracks, suspected decay, heavy crown bias, uncertain stress, nearby targets, or movement that does not match the plan. These conditions need a qualified site assessment.
(This article was written by one of our staff writers, Julian Barrett. Visit our Meet the Team page.)
