EC 1124Revised January 1997$1.50

LoggingFelling and Bucking Techniques

for Woodland OwnersJ. Garland and D. Jackson

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ContentsClothing and Equipment ...................

Chain saws ...................................Timber Felling Plans .........................Evaluating Tree Felling Conditions ..

Hazardous conditions ...................Danger trees .................................

Assessing the Tree...........................Escape Path .....................................Tree Felling .......................................

Sighting direction-of-fall ..............4Matching saw cuts ........................Undercuts .....................................

Conventional undercuts ............Humboldt undercuts ..................Open-face undercuts ................

Back cut ........................................Bucking Procedures .........................Hazards during Bucking ....................Springpoles .......................................Chainsaw Reaction Forces .............Limbing .......................................... 1Problem Trees ................................

Multiple stems ........................... 1Leaning trees ............................. 1

Correcting for moderate lean . 1Felling against the lean .............. 1Hangups ..................................... 1

Summary Checklist ........................ 1For Further Reading ....................... 1

OSU Extension publications ..... 1Other publications ..................... 1

Skills in felling and bucking timber are useful for manywoodland owners. Safe and effective use of chain sawpromotes efficiency in thinnings, salvage operations,hardwood removals, firewood gathering, and full-scale

harvesting operations. However, chain saws are dangerous! Duse them without adequate skills and preparation, including phcal conditioning and experience in chain saw use and mainten

This publication is not an in-depth felling and bucking skillsmanual. Rather, it’s a guide to basic principles and proceduresinexperienced timber cutters. Its intent is to help you improve ybasic skills in manual timber felling and bucking techniques. Tpublication does not cover all state or federal rules that may apto felling and bucking.

Proper felling and bucking also can affect timber values andrevenue received from timber sales. These topics are coveredbriefly in this publication, and are discussed in greater detail inother publications (see “For Further Reading,” page 16).

A good approach to skills development involves first under-standing basic principles. Many are outlined in this publicationchain saw operator manuals, and in other references.

John J. Garland, Extension timber harvesting specialist, and David J. Jackson,Extension timber harvesting specialist; Oregon State University.

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You can develop skills for effec-tive chain saw operation by cuttingtimber that is already on the ground.This practice also will help improvebucking skills.

Consider arranging practicesessions with experienced timbercutters to learn felling techniques forstanding timber. Start with live, smallstraight trees of sound, green wood.Ordinarily, if problems occur, smalltrees will not require the use ofmechanized equipment.

Never work alone with a chainsaw! Always have someone nearby tprovide immediate assistance shouldan accident occur.

Clothing andEquipment

You must have the tools andsupplies necessary for your job.Protective clothing and equipment fosafe and productive timber felling anbucking include the following:• Hardhat (protective helmet)

• Eye protection (screens, glasses, goggles)

• Hearing protection (ear muffs orplugs)

• Safety chaps or special pantscontaining protective inserts

• Gloves

• Boots (caulked boots provide moresecure footing and are preferred bprofessionals)

• Comfortable clothing (loose fitting,cuffless pants)

• First aid kit

• Fire extinguisher

• 3–5 lb axe (for pounding wedgesand cleaning out the undercut)

• Saw gas, bar oil, and lubrication(for the tip of the bar)

• Wedges (soft plastic)

• Chain file with handle and properfiling guide, plus gauges to checkfiling results

• Plumb line (string with a weight atthe end to provide a vertical line fodetermining lean of a tree)

• Peavey or chain (to free hangups)

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Chain sawsThe chain saw should be modern

and in good repair. Do not attempt atask as dangerous as felling trees wa poorly functioning saw. Check youchain saw for the following:• The chain saw should be equippe

with a chain brake that functions athe manufacturer intended.

• The length of the bar should not bexcessively long (i.e., not muchgreater than the diameter of thetrees you expect to cut).

• The chain should be sharpenedcorrectly. Correct sharpening willensure straight cuts and removal owood “chips” rather than sawdust.You may find a saw equipped with

saw dogs (sharp, pointed teethattached to the saw housing near thbase of the bar) easier to control.

Timber Felling PlansThe way you fell timber influences

skidding or yarding activities. Makefelling and skidding plans beforecutting begins (Figure 1). A plannedsystem of skid trails, combined withproper felling-to-lead, can greatlyhelp skidding timber to an accessroad. Use coloredflagging to mark skidtrails before skiddingoperations begin.“Designated skidtrails” will helpprotect your residualstand and soil bylimiting machinetravel to specificareas.

“Lead” refers toplanned, directionalcutting of timber. Foreither ground-basedskidding or cableyarding, trees “felled-to-lead” are angledapproximately 30 to45 degrees to eitherside of the skid trail orskyline cableway.Timber felled usingthis procedureresembles a herring-bone pattern. Thispattern reduces timberbreakage and damageto the remaining stand.This felling pattern is Figure 1.—A

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useful particularly for thinningoperations or partial cuts. In smalltimber, either tops or butts of treesmay face the skid trail.

Trees felled out-of-lead typicallyare angled 90 degrees or more awayfrom the skidding direction. Duringskidding, felled timber must be pulledtoward the desired direction of travelIf you must swing timber into a skidtrail, it can badly scar standing treesor crush young regeneration. Safetyalso can be jeopardized when timberis pivoted toward the direction oftravel.

In a clearcut operation, arrange thcutting pattern so trees are felled intothe open area rather than into standitimber. When standing timber isbrushed by falling trees, limbs or topmay be broken and propelled back-ward toward the cutter. They also mahang dangerously overhead and fallunexpectedly.

In thinning operations, fell treesinto openings. Pay special attention toverhead hazards. Work up the hilland across the slope to minimizehazards from logs or trees sliding orrolling toward you.

planned felling pattern (not to scale).

Skid trail

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Trees felledout of lead

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Evaluating TreeFelling Conditions

Hazardous conditionsUnder some conditions, timber

felling should be considered unsafe.Such conditions involve weather,terrain, and operator skill. Whenunsafe conditions exist, inexperiencecutters should either seek assistancfrom a professional or postponeactivities. Under these conditions,professionals can minimize risks thamay create life-threatening conditionfor beginners.

Unsafe conditions include thefollowing:• Light, intermittent wind may be

sufficient to tip a tree in the wrongdirection or cause other problemsthe stump. If tree tops are movingdo not attempt to fell timber.

• Fog hampers vision upward intothe tree crown. Detached limbs antree lean can be obscured. If thedirection-of-fall is not visible,someone could enter a danger arewithout being seen.

• Snow and ice may cause limbs,heavy bark, or tree tops to fallsuddenly.

Danger treesTrees that present special felling

hazards are termed “danger trees.”Skills and experience beyond those a beginner are required to fell thesetrees. Some kinds of danger treesinclude the following:• Standing dead or rotten trees

constitute a serious hazard to yousafety. Such trees are referred to snags. Snags are beneficial forvarious bird and mammal speciesAfter they fall, snags decompose,further enriching soil nutrients.

However, snags often haveproblems with rot, heavy bark, andloose limbs. Wind can cause snagto topple without warning. Snagscan react unpredictably whenstandard cutting techniques areused. Due to their deterioratedcondition, snags should be felledonly by an experienced cutter.

• Trees with “pistol butts” are foundon slumps and slides. Their distincshape results from not achievingnormal vertical growth, and they

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often require specific cuttingtechniques.

• Trees with brittle or rotten heart-wood may require the attention ofan experienced cutter. Alder,maple, and madrone often havethese characteristics.

• Utility lines, buildings, steepslopes, or trees whose length willallow them to cross roads cancause special problems. Professioals use cutting techniques, wedgehydraulic rams, cables attached tomachinery, and their expertise tosolve problems.As an inexperienced cutter,

exercise caution when attempting tofell or buck timber unfamiliar to you.If you are unsuccessful, your attempmay cause additional danger to theprofessional ultimately responsible fofelling the danger tree.

In preparation for all fellingoperations, you must determine aclear direction-of-fall. If you cannotmake this determination, leave thetree standing until you obtain assis-tance.

Mark any potentially hazardoustree with highly visible, coloredflagging (special “danger tree”flagging is available). This warningwill alert others to the presence of adanger tree.

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dFigure 2.—Determining the lean witha plumb line.

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Assessing the TreeA careful evaluation of felling

conditions will guide you in makingfelling cuts. Assess potential hazardsto determine whether or not assistancis needed. For each tree to be felled,beginning cutters should go through amental checklist containing itemssimilar to those listed at the close ofthis publication (see “SummaryChecklist,” page 15). Failure torecognize a key piece of informationcould threaten your safety.

Always begin the felling processby determining tree lean. You areinviting disaster by cutting a treewithout evaluating its lean. The leanof each tree is unique. Do not assumyou can assess the direction a treenaturally will fall simply by lookingat it. For example, trees growing onslopes often lean downhill. Even treethat appear to lean uphill may bestraight or lean slightly downhill.

You can estimate the amount oflean using a plumb line made from asmall weight and a piece of string(Figure 2). By looking at the tree’slean from at least two sides at rightangles, you can determine thedirection of natural fall.

First, stand uphill and to the side othe tree. Then, assess the tree’s leanfrom right angles to that position. Ifthe natural lean is toward the chosendirection-of-fall, use standard cuttingtechniques. If the natural lean is awafrom the desired direction-of-fall,special cutting techniques will beneeded.

Another factor that influencesdirection-of-fall is the pattern oflimbs. Limb loading can result from alarge limb growing on one side of thetree. This condition will cause a treeto be pulled out-of-lead as it falls.Limbs from adjacent trees mayinterlock, making it difficult to start atree’s fall in the desired direction.Specific cutting techniques canovercome problems related to limbsas well as to lean.

As you examine a tree for lean andlimb loading, look for loose limbshanging overhead. Loose bark alsocan be a hazard. Snags and trees wioverhead hazards are particularlydangerous. Saw vibration or treemovement can release the objects,causing them to crash downward.If you plan to cut such trees, arrangefor an additional person to watch

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overhead and warn of hazards whileyou attend to responsibilities at thestump.

Always determine if rot is presentwhere your felling cuts will be made.Controlling a tree during fellingrequires that cuts be made in soundwood. Felling cuts made in areascontaining rot can cause a tree to spor shatter, with serious results for thetimber faller.

Expect to find rot in standing deadtrees. Fungal fruiting bodies known aconks also indicate rot. Tree speciessuch as hemlock, true firs, cedar, ansome hardwoods are known to contastump rot.

If rotten wood is present, compen-sate for it by leaving extra soundwood. As another alternative, youmay want to consider changing thedirection-of-fall.

Trees suspected of containing rotmay be bored using the saw bar todetermine if rot is present. Whilemaintaining the saw bar in a verticalplane, make a boring cut by pushingthe saw bar directly into the treestump within the area suspected ofcontaining rot (Figure 3). These cutswill not weaken the tree if they aremade below the point where felling

cuts are planned. When boring,maintain firm saw control to preventchain saw kickback.

Make your cuts parallel with thedirection-of-fall, and assess the chipsor sawdust produced. Sawdust fromrotten wood is quite different fromchips produced from sound wood. Asan exercise, cut into logs known tocontain rotten wood and examine thesawdust.

Figure 4 indicates additionalfactors you should consider whenevaluating a tree to be felled. For trethat have butt swell, make felling cutfar enough into the tree to penetratebeyond the swelled area. Thisdistance will equal a projection of theupper bole downward into the buttswell. Snow break, prior damage,double trunks, or physical differenceamong various tree species canweaken trees, affecting your cuttingprocedures.

Figure 3.—Boring the stump to detecthe presence of rot.

Hidden rot

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Figure 4.—Evaluate tree to be felled.

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Escape PathClear at least one escape path for

each tree you plan to fell (Figure 5).A clear, unobstructed path will enablyou to move quickly to a safe positioafter dropping the saw at the treestump. Your path should be angled45 degrees backward and away fromthe direction-of-fall. Because manyfelling accidents occur to cutters whoremain within 15 feet of the stump,clear an escape path greater than thdistance. The path should be free ofbrush and other obstacles.

Sometimes, obstacles locatedaround the base of a tree may obstruyour escape or create awkward fellinpositions. Normally, stumps are cut alow to the ground as possible. How-ever, if obstacles jeopardize yoursafety, you may need to cut higherstumps. This practice will allow youto maintain a standing positionnecessary for escaping quickly.

Beginning cutters should seekprofessional assistance if rocks,multiple stems growing from onestump, steep slopes, difficult terrain,or other obstacles hinder a quickescape. An escape route can becritical if a tree does not fall asplanned.

Tree Felling

Sighting direction-of-fallChain saw handles are designed

be used as a sighting mechanism.Saws with curved handles have “sigmarks” imprinted on the saw housingWhen making your undercut, sightindown the handle of the saw or thesight marks will allow you to “aim” atree toward its desired direction-of-fall. Become familiar with yourparticular equipment and its sightingaccuracy. Check where the tree fallsin relation to the sight of your saw.

Matching saw cutsBefore making any undercut, it’s

vital to understand the importance omatching saw cuts. In order to contra tree’s intended direction-of-fall, yomust make felling cuts that do notoverlap. Ideally, your cuts will matchperfectly. As a tree tips toward itsdesired direction-of-fall, cuts matcheproperly will close uniformly alongtheir line of intersection.

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Figure 5.—Clear, unobstructed escape paths needed.

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45°

Escape route

Escape route

If your cuts do not match, thedifferential rate at which an undercucloses dramatically alters a tree’sdirection-of-fall (Figure 6). You maylose directional control. The treecould split vertically, creating extremedanger for the cutter. Figure 7indicates how forces from a fallingtree are redirected when an undercudoes not close uniformly, creating a“barber chair.”

To ensure matching cuts, use aheavy crayon to sketch the shape anlocation of your undercut. Mark yourintentions with your axe (Figure 8).Beginning cutters always should havanother person on the opposite sidethe tree to alert the cutter if correc-tions are needed.

UndercutsOnce you understand matching

cuts, the first step in felling any tree to make an undercut near the tree’sbase. An undercut allows a tree to bguided toward a preferred direction-of-fall. To make an undercut, followthe instructions below to remove awedge of wood whose width andvolume are compatible with the tree’size and your cutting technique.

In order to effectively complete anundercut, your saw should beequipped with saw dogs to help gripand hold the saw’s position. Usingsaw dogs, you can maintain constancontact between the saw bar and thewood being cut. Saw slippage will bereduced, and your personal safety wbe improved. As an undercut is madthe saw is rotated around the base otree. With each new saw position, thsaw is pivoted, allowing the dogs tobite deeply into the tree bark.

Three types of undercuts com-monly are used for felling timber—the conventional, the Humboldt, andthe open-face undercuts (Figure 9a,b,

Conventional undercuts. Theconventional undercut is acceptedworldwide and is the easiest methodfor beginners to learn. Select adirection-of-fall and make a horizon-tal cut at right angles to your intendedirection-of-fall, sighting with yourhandle or saw’s sight marks. Thedepth of this cut should be one-fourtto one-third of the tree’s diameter(Figure 9d).

Angle the next cut so it meets thedeepest point of the horizontal cutexactly at both corners. In so doing, wedge of wood will be cut free. Whe

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aFigure 6.—Cuts must match properly.

Uniform andlevel cut

Uniform versusuneven undercuts

Slanted anduneven cut. . .

the unequal pressure will causetree to fall out of lead.

Cut hingewood

If cuts do not match, the hinge woodis cut away

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making your undercut, try to create vertical opening approximately one-fourth the tree’s diameter. After sompractice, you may be able to anchorthe saw at the near point and matchyour cuts with greater accuracy.

Once the cuts match, chop out thwedge with your axe. After removingthe wedge of wood, place your saw

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the undercut, and use it as a device sight the desired direction-of-fall.Since the tree won’t fall in the desiredirection if it isn’t aligned to do so,make corrections to the cuts asneeded.

Humboldt undercuts. An under-cut popular in the west is theHumboldt undercut. It generally is

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oused when felling medium to largetimber. The horizontal cut of theHumboldt undercut is made similar tthe conventional undercut. Unlike thconventional method, the wedge ofwood removed using the Humboldt itaken from the stump instead of thebutt log.

Figure 7.—Barber chair from mis-matched cuts.

Figure 8.—Mark intentions to be surecuts match.

Saw guide markaligned with

direction-of-fall

Desired hinge

Face cut

Direction-of-fall

Marked point withcrayon or axe

a. Conventional b. Humboldt c. Open-face

d. Depth of undercut

Figure 9—(a, b, and c) Types of undercuts; (d) Depth of undercut, and usinaxe to check direction-of-fall.

Direction-of-fall

1⁄5 to 1⁄3 tree diameter

Figure 10.—Sight down open cut to help match lower cu

45° top and bottom cutsthat match. Depth about1⁄5 tree diameter.

Sightline

Sightline

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Open-face undercuts. The open-face undercut combines features ofthe conventional and the Humboldt.The wedge of wood removed usingthe open-face undercut comes fromboth the butt log and the stump. Theopen-face cut originated in the Nordcountries and is used for felling smastraight trees. Do not use saw dogswhen making the open-face undercuor back cut.

Make an open-face undercut asfollows. After sighting the tree’sintended direction-of-fall, start withthe top cut first. Keep the sawhorizontal while the angled cut ismade. To make the top cut, cutdownward at a 45-degree angle. Thesight down the top cut to make surethe bottom cut will exactly meet at thintended angle (Figure 10). To makethe bottom cut, cut upward at a45-degree angle. When cuts at thebottom and top intersect, they willform a 90-degree angle.

The depth of your cuts shouldequal about one-fifth the tree’sdiameter. It’s important that the topand bottom cuts match and are notovercut at their corners.

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Back cutA back cut is made horizontally. It

is the final cut that causes the tree tofall. The back cut is approximately1 inch higher than the undercut. Whemaking your back cut on slopingground, always work from the uphillside of the tree.

Before you begin to make the baccut, stop your saw and give a warnincall. Indicate clearly your intendeddirection-of-fall. If other people are inthe vicinity, do not proceed with theback cut until definite communica-tion, indicating a safe position, hasbeen established.

As the back cut is made, do notallow it to intersect the undercut.Instead, you should leave an unbrokehinge of uncut wood between theundercut and back cut. This uncutwood allows you to control the tree’sspeed and direction-of-fall. A hori-zontal back cut whose hinge width is1 to 1.5 inches should be adequate fcontrolling trees whose stump diametis less than 24 inches (Figure 11).

If the tree’s diameter is sufficient,insert a falling wedge in the back cutas soon as possible to prevent the tre

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from sitting back on your saw bar.Wedges also can be very useful forcorrecting tree lean.

Make your back cut moderatelyfast so that wood from the falling treeis not pulled from the stump or buttlog. Continue quickly before unex-pected winds adversely influence youintended direction-of-fall. Checkfrequently to make sure your back cuis progressing satisfactorily. Takecare to avoid cutting off the corners oyour hinge wood. Overcutting theback cut can alter a tree’s direction-of-fall (Figure 12). Glance frequentlyinto the tree crown to check forhazards overhead.

As the tree begins to fall, removethe saw from the cut and immediateldrop it behind the stump. Proceedquickly along your predeterminedescape path. Retrieve your saw afterthe tree is on the ground.

Small trees may require that theback cut be made before the undercuThis will enable you to better accom-plish directional felling by firstplacing a wedge in the tree. Practice

Figure 11.—Making the back cut.

1"

1"–11⁄2"hingewood

Wedge

1"–11⁄2"hingewood

Direction-of-fall

Hinge woodbreaks astree falls

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Figure 12.—Overcutting the back cut.

Hinge wood cut off

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this technique with an experiencedcutter before attempting it on yourown.

Occasionally, you may wish to fela tree whose diameter is greater thathe length of your saw bar. Undersuch circumstances, the back cut mbe made utilizing a series of cuts(Figure 13). Utilizing a series of cutspreserves the strength of the hingewood until the final cut is made. Asyou make the series of cuts, wedgesmay be needed to maintain control othe tree.

Bucking ProceduresBucking involves cutting trees into

log segments whose lengths arespecified by mill requirements,including trim. Buckers should makecuts square to the logs, correctlymeasure log length, and maintain lovalue. You must carefully evaluateeach bucking situation. Whenbucking, maintain a safe workingposition on the uphill side of buckedlogs.

The first consideration in safe logbucking is to determine the directionlog segments will move after the cutis completed. You can make thisdetermination by following one basicprinciple: “cut the compression woodfirst.”

The position of the tree createsinternal forces in wood fibers. Figure 1illustrates the difference betweencompression wood and tension wooCompression wood is located alongthe inside of a curved or bent piece wood. In compression wood, woodfibers are pushed together. Tensionwood is located along the outside ofpiece of wood. In tension wood, woofibers are pulled apart.

Figure 13.—Using a series of cuts.

Wedge

Undercut

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Figure 14.—Wood in tension and compression.

Wood in compression

Wood in tension

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Figure 15.—Cutting compression wood first.

Wood in tension

Wood in compression

Wedge cut out

Top bind

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Top bind

b.

Bottom bind

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The concept of cutting compressiowood is illustrated in Figure 15a,b,c.Generally, cutting compression woodfirst allows a log to move in thedirection of tension. Gravity also willact on trees during bucking, causingthem to roll, slide, or fall.

It may be difficult to evaluatecorrectly the exact location ofcompression wood and tension woodTherefore, always keep an axe andwedges available for releasing apinched saw bar.

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The term “bind” is used to indicatthe location of compression wood.Bucking principles and proceduresdescribed previously also apply totrees lying in a horizontal bind.

When bucking large timber, yousometimes must make a number ofcuts in order to release the tensionwood. As tension wood is cut, it is nuncommon for wood beneath the cuto break away.

When bucking smaller logs, twocuts normally will be adequate. The

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first bucking cut will be shallow. It’sintended to sever only a small amounof compression wood without bindingthe saw. A second cut will release thtension wood.

Hazards duringBucking

You may encounter severaldangerous situations during logbucking. On sloping terrain, remem-ber to make your final bucking cutfrom the uphill side. This will preventbucked logs from rolling downhilltoward the bucker (Figure 16).

Trees sometimes are subject to enpressure. This occurs when trees liealong a slope and are supported alontheir entire length (Figure 17). Afterthe first cut is made, you couldbecome endangered by the upper losliding downhill. In order to safelybuck such logs, you must make twocuts.

The first cut, on the log’s lowerhalf, should be offset and uphill. Thesecond cut, on the log’s upper half,should be downhill. Inserting a wedgwill help you keep the upper cut openIf the logs will not separate, markthem with brightly colored flagging toserve as a warning to those doing thskidding or yarding.

Windfalls cause dangerousbucking problems and are difficult toevaluate. Rootwads may act unpre-dictably when cut away from thestem. Roots bent underground canapply pressure, causing a rootwad toupright itself when cut. An uprightedrootwad may either roll onto thebucker or cause the bucked log toreact unpredictably.

Analyze each bucking situation foits unique circumstances. Assess itscompression/tension wood, potentialfor movement, and safe positionsfrom which to make bucking cuts.

SpringpolesSpringpoles are small trees bent

under by larger trees you have alreacut (Figure 18). They are underextreme tension and can reactunpredictably when improper cuttingmethods are used. Attempt to cut aspringpole only if you can reach apoint where a right angle is formed bthe lines of the bent tree.

Figure 16—Make final bucking cuts from a safe position.

Direction cut logswill move

Safer location insidebind and on uphillside

Figure 17—Trees/logs subjected to end pressure.

End pressure

Cut 2

Cut 1

Figure 18—Cutting springpoles.

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Note the extreme tension in theouter fibers of the tree at this point.Stand in the safest position to the sidof the springpole and check where thends of the springpole will movewhen they are cut. Then, make aseries of shallow cuts in the compresion wood opposite the point ofmaximum tension.

Alternately, you can shave thecompression wood along the samearea with the side of the saw. Experence shows this releases some of thtension, and successive cuts cancontinue to release additional tensioby cutting the compression wood.

For larger springpoles, or if there no place to stand while cutting, markthem with colored flagging and pullthe trees off with lines from a machin

Chainsaw ReactionForces

Chainsaw reaction forces resultwhen the power of the rotating chainis transferred from the action ofcutting wood to the saw and theoperator. The common reactive forcare kickback, pushback, and pull-in.Reactive forces may cause the saw move rapidly and unpredictably, orcause operators to lose control of thsaw or to lose their balance.

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Kickback is oneof the major issuesin maintaining safebucking andlimbing practices. Itis the sudden trans-ferral to the operatorof uncontrolled chainsaw cutting power.Movement isunpredictable andmay cause seriousinjury or death.

Kickback can occurdue to many circum-stances. Inaccuratelyhigh or low depthgauges, or dullcutting teeth resultin a poorly main-tained saw chain.Saw teeth that fail to cut wood cancause the saw to kick back. Kickbacalso can occur when your cuttingmoves from soft, live wood to hard,dead wood. Kickback is more likelywhen cutting with the top quadrant othe saw bar nose.

Figures 19a,b illustrate criticalangles on a saw bar nose wherekickback during cutting might bemore likely. If the nose of the barstrikes an obstacle without cutting it,the saw will kick up and back towardthe operator.

Many kickback-related injuriescould be prevented by the following:• Control the saw using a solid, two

handed grip with thumbs wrappedaround the saw handles.

• Maintain good footing and posi-tions for preventing kickback bynot standing in line with potentialbar movement.

• Know where the tip of the bar is aall times.

• Anticipate kickback situationswhen you are making a boring cutBore at an angle upward ordownward rather than straight intothe log, and begin boring cuts usinthe bottom of the saw bar nose.

• Keep track of the kind of wood youare cutting (live versus dead).

• Maintain the saw’s chain brake.However, do not depend on itschain-stopping feature alone.

• Sharpen the saw chain according the chain manufacturer’s directionUse the available guides and

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Figure 20—Pinc

Chaindirectio

Chdir

Chdir

Chaindirection

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gauges to help sharpen your chainor have a saw shop do it for you.

• Use low-kickback bar designs andanti-kickback chain.If the saw chain becomes pinched

the saw may move in the oppositedirection to chain movement. If thetop of the bar is pinched, the saw willpushback into the operator. If thebottom of the bar is pinched, the sawwill pull-in, pulling itself and theoperator forward (Figure 20a,b).

To reduce the potential for pinchedchain, always start the cut with thesaw chain running at full speed.Watch for compression wood thatwould cause the chain to bind.Consider using a wedge to help keepthe saw cut open.

Figure 19—Avoid chain saw kickback

a.

b.

Criticalangles

Chain direction

Chain direction

Obstacle hit herewill cause sawbar to kickup towardoperator

hed chain forces.

a. Push back

b. Pull-in

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ainection

Saw movement

Saw movement

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Figure 21—Cutting limbs.

a.

b.

Cut 1

Cut 2

Cut 2

Cut 1

Cut 2

Cut 1

Cut 3 toclean up stub

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LimbingLimb removal may appear to be

relatively simple; however, it is time-consuming, and accidents often occuYou may encounter problems whenlimbs supporting the stem cannot beremoved safely. Predicting themovement of cut limbs can beparticularly difficult. You mustevaluate limbs under pressure todetermine the location of compressioand tension wood (Figure 21a,b).

Awkward cutting positions arecommon during limbing operations.Unsure footing may jeopardize yoursafety when moving between limbingpositions. As limbing operationsproceed, always keep the log betweeyou and the saw bar. Protect your legwith safety pants or chaps. Do notattempt to stand on the tree stemwhile limbing it. Instead, work fromthe side of the stem.

You may benefit from using adelimbing technique developed in theNordic countries for coniferous trees.It also may be modified for use withhardwood trees. Figure 22 showsappropriate positioning for thismethod. Think of this method’smovements and positioning as if theywere a practiced athletic drill, or evendance movements. The followingdelimbing steps are suggested for aright-hand saw user:1. Usually start at the butt of a tree

and cut the limbs in front of you,keeping the saw to the right side oyour body. Cut only those limbsthat can be reached comfortablywith the saw tucked close to yourright side.

2. At the end of the sweeping, cuttingmotion, change your grip on thesaw handle to the left side of thesaw, reposition your feet, and turnthe bar parallel to the stem. Use thtop of the bar to slide along thestem. Cut the limbs on top of thestem toward the butt of the treewhere you started.

3. Reposition your grip to the top ofthe saw handles and turn the saw it rests on top of the stem. The fronof the saw will be on top of thestem, and the bar will be in avertical position on the oppositeside of the stem. Use the stem asleverage point and slide the sawforward, cutting the limbs on theopposite side of the tree. The stemsupports the weight of the saw and

ot

is used to lever the saw into positiofor cutting the limbs. Cut what youcan reach without overextendingyourself.

4. With the saw resting on the stem,and the bar on the opposite side,step forward to a new position andface the stem. Grip the saw on theleft part of the handle, bend yourknees keeping a straight back, ancut the limbs on the bottom of thestem in a sweeping motion towardthe butt of the tree. Use the top ofthe bar, keeping the bar parallel tothe bottom of the tree and pressedagainst the stem during the move-ment.

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n5. At the end of the sweeping move-ment, reposition the left hand to thtop of the handle and begin Step 1again.

With practice, these steps will forma pattern that has several benefits. Tlower back is kept straight, and thelarge muscles of the legs do most ofthe work. The weight of the saw isoff-loaded to the tree stem for muchof the time, rather than carried by thearms. Legs are better protected,especially when moving to a newposition with the saw on the oppositeside of the tree stem. Nothing in thepattern restricts handling unusualcircumstances when they arise.

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Figure 22—Nordic delimbing technique. Arrows indicate saw movement ordirection up the tree stem.

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2

31

3

4

2

1

Side Views Top Views

Arrowsindicatedirection ofmovementup the treestem

Footpositionsapproximatelocations forsequence ofsteps

Arrows indicatesaw movement

Arrows indicate saw movement

1

2

3

4

1

2

3

4

1

2

3

4

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Problem Trees

Multiple stemsMultiple stems growing from one

stump can be unusually difficult forinexperienced cutters. You may findyourself in awkward cutting positionsand have difficulty determining thedirection-of-fall. Normally, youshould treat each stem as if it were asingle tree.

Felling multiple stems requires thayou begin with the outermost stem.Fell the stem in its natural direction-of-fall. As you cut each stem, be

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aware of overhead hazards. Severalescape paths may be required.

Occasionally, conifers will havedouble stems originating from a singstump. If the split occurs at a heightgreater than you can reach with a sathere may be sufficient wood holdingthe two stems together to enable youto fell the tree as if it had a singlestem. Its direction-of-fall should beperpendicular to the horizontal longaxis of the two stems (Figure 23).Regardless of fork height, examinethe trunk cautiously. Locate a well-defined vertical seam or scar indicating separation between the two stem

If the split occurs at a height youcan reach with a saw, fell the stemsseparately. Cut vertically down theseam with your saw. Select thedirection-of-fall on one of the stemsand make an undercut. Make yourback cut, leave an adequate amounthinge wood, and fell the tree. You cafell the remaining stem either with oragainst the lean (Figure 24).

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Figure 23—Felling two stems togethe

Front view

Long

axis

Direction-of-fall

Side view

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kFigure 24—Felling stems separately.

Front views

Cut down-ward toseparate

Boringbackcut

Direction-of-fall

Fell remainingstem with lean orcorrect for lean

Direction-of-fall

Leaning treesTrees that lean heavily are prob-

lems for even the most experiencedcutter. As a beginner, do not attemptto fell trees that lean heavily until yougain skills from an experienced cutteBasic skills will allow you to fell treeshaving moderate lean. Obviously,trees can be felled with the leastamount of difficulty toward thedirection in which they lean naturally

Begin by selecting an appropriateundercut. Depth of the undercut willbe approximately one-third the tree’sdiameter. Pay careful attention tomatching your saw cuts. Dependingupon the tree’s size and its degree olean, you might use one of thefollowing types of back cuts.1. For trees whose diameter-at-brea

height (dbh) is less than 12 inchesuse a standard back cut. Make theback cut rapidly because a substatial amount of hinge wood willbreak away quickly. As the treebegins to fall, continue cutting untidesired hinge wood thickness isachieved (Figure 25a).

2. For larger trees with more lean, yomay choose to bore the center ofthe back cut. This will reduce thelikelihood of producing a barberchair (Figure 25b). After the treehas been bored, make a quick bac.

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,

cut using the remaining wood oneither side of the center cut as ahinge.

3. Large leaning trees may requiretwo side cuts. Wood that remains ithe tree’s center portion will holdthe tree. Make a back cut quickly inorder to release the remainingwood. However, a substantialamount of wood will break away asthe tree falls (Figure 25c).

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Figure 25—Felling trees with the lean.

a.

b.

c.

Larger hinge

Chain topreventsplitting

Deeper undercut

Direction-of-fall and lean

Direction-of-falland lean

Boring cut

Direction-of-falland lean

Side notch

Side notch

Final cut

Correcting for moderate lean.“Holding wood” may be used todirectionally fell trees with moderatelean. Holding wood is additionalwood left on the hinge to provide aholding force opposite the direction onatural lean (Figure 26). Usually,hinge wood should not be cut becauit helps control a tree’s direction andrate of fall.

Felling against the leanTrees that lean heavily can be

felled against their lean. However,you often need considerable judgmegained from years of cutting experi-ence. Felling against the direction ofnatural lean is accomplished usinghand tools and special felling tech-niques.

You will need two or more softplastic wedges to lift the leaning treeMake a shallow undercut approxi-mately one-fourth the tree’s diameteto achieve a longer lever arm for thewedges to lift. Clear away the barkwhere you will insert the wedgesunder the point of the tree’s lean. Stthe back cut there, insert both wedg

as soon as there is ample room, andkeep them tight in the cut.

Proper wedging can lift a tree intoan upright position. Ideally, wedgeswill provide approximately 1 inch oftree lift. Alternately cutting the backcut and wedging will shift a tree awafrom its natural lean, through avertical position, and toward a moredesirable direction-of-fall.

If additional lift is required, youcan place one wedge on top ofanother. This practice will almostdouble the lifting capability of yourwedges. Continue the process untilthe tree is relieved of its lean andstraightens (Figure 27).

A hinge of wood always is needeto maintain tree control. An experi-enced timber cutter can determinewhether to increase the depth of theback cut by monitoring the amount oforce needed to drive the wedges.Removing the bark will allow you tomonitor the effectiveness of yourwedge. Once you have achieved anadequate hinge from the back cut,continue wedging until the tree falls.

The following guidelines indicatethe maximum amount of lean that

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wedging can correct. Values areapproximate and apply to trees whosstump diameter varies between 12 an24 inches.Amount of lean (ft) Tree height (ft)

4 507 100

10 150Using wedges, it may be possible

for experts to fell trees with evengreater lean. Hydraulic rams can beused to lift leaning trees. Cablesattached to heavy machinery also mabe used to pull a heavily leaning treeinto an upright position for directionafelling.

Figure 26—Correcting for moderatelean using holding wood.

Leave more holding wood tocorrect for lean

Lean

Direction-of-fall

Figure 27—Felling against the leanusing wedges.

Direction-of-fall

Lean

Wedges

Direction-of-fall Lean

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HangupsEventually, every timber cutter

will create a hangup. Hangups occurwhen a felled tree becomes lodged ina standing tree. Once a hangupoccurs, find a safe location where yocan carefully evaluate the situation.Lodged trees often are held only bytheir limbs, which can break andrelease the hangup to fall suddenlyand unexpectedly. Never attempt tofell the tree in which a hangup islodged!

Always keep the tree in which thehangup is lodged between you and thangup itself. If you are unable to frethe hangup safely, seek advice froman experienced cutter. Two techniqucommonly are used to safely get thehung tree on the ground (Figure 28).The first is most effective for treeswhose diameter is less than 18 inche1. Cutting away the butt. Making a

cut part way up the butt of the treemay clear the hangup. First, makeshallow V-shaped cut on the top othe tree (see “Bucking”), then maka cut from the bottom. Severing thstem may cause the tree to dislodgitself from the hangup.

Two or more of these sequencesmay be required to get the treeclear. If possible, between each ofthese sequences, try to roll the treclear using a peavey or similar tooWatch the top of the hangupcarefully, and be prepared to makean escape.

2. Felling another tree into thehangup. Sometimes a hangup canbe cleared by felling an adjacenttree into the hangup. The treeshould strike the hangup withsufficient force to break either thetree or the obstacle.If the original hangup causes

another tree to become lodged, uselines from machines or seek assis-tance from an experienced cutter. Donot compound a safety problem bybuilding a tepee of hung trees. Markthe hangups with colored “danger”ribbon and get help.

Specific skills are required to cutproblem trees. Evaluate each treecarefully and do not attempt to fell atree if you have any doubts aboutwhat will happen. Seek assistancefrom a more experienced professiona

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el.

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a.

First make a shallowcut on top or cut outa wedge

Cut from bottom

Figure 28—Cutting down hangups by (a) cutting away the butt, and (b) fellinanother tree into the hangup.

b.

Fell this tree acrosshung tree

Do notattempt tocut this tree

Hung tree

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Summary Checklist

en er-

ghes.

Timber cutters must recall and utilize a vast assortmof information. The following checklist will assist you inthis exercise. Ideally, the checklist will become a set ofmental habits, but explicit reminders will be needed.Consider making a pocket card checklist for your use.

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t,

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t Felling and bucking timber can be extremely dangous. However, you can make the process safer throuproper use of safety equipment and cutting techniqu

1. Prepare to perform the job safely.• Personal protective equipment (hardha

ear and eye protection, safety pants orchaps, first-aid kit, etc.)

• Tools and supplies (axe, wedges, peavetc.)

• Saw and chain maintained

2. Evaluate cutting conditions.• Weather• Escape routes• Cutting positions• Timber felling pattern

3. Evaluate the tree and its direction-of-fall.• Did you use a plumb bob?• Were lean and limb loading determined• Is rot present?• Is this a danger tree?

4. Make the undercut.• Are the cuts level? Do the cuts match u

Is the face cleaned out?• Does the undercut face the direction-of

fall?• Is there proper depth?

,

5. Make the back cut.• Shout a warning and listen for replies.• Use wedges as needed.• Make the back cut approximately 1 inch

higher than the undercut.• Don’t cut off the holding wood.• Leave a hinge to control the fall.

6. Move to safety and watch for overheadhazards.• Is help needed to clear a hangup?• Are hazardous, broken limbs left in

adjacent trees?

7. Evaluate the limbs before limbing.• Look for limbs under tension.• Look for springpoles.

8. Determine if the bucking cut can be madesafely.• Determine the location of compression

wood, tension wood, and the way thebucked pieces will move.

• Buck from the uphill side.

9. Never work alone!

10. Never work fatigued!

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For Further Reading

OSU Extension publicationsTo order copies of the following

publications, send the publication’scomplete title and series number,along with a check or money order fothe amount listed, to:

Publication OrdersExtension and Station

CommunicationsOregon State University422 Kerr AdministrationCorvallis, OR 97331-2119Fax: (541) 737-0817If you would like additional copies

of this publication, Felling andBucking Techniques for WoodlandOwners, EC 1124, send $1.50 percopy to the above address.

We offer discounts on orders of100 or more copies of a single title.Please call (541) 737-2513 for pricequotes.

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Garland, J.J., Increasing ValuesThrough Improved Bucking PracticesManufacturing Logs, EC 1184(Oregon State University, Corvallis,reprinted 1993). $2.50

Other publicationsChain Saw Manual, 2nd edition

(American Pulpwood Association,Danville, IL, 1988).

Chain Saw Safety Manual, Stihl,Waiblingen, Germany, nd. (Mentionof trade names does not constitute aendorsement. Many saw manufacturers offer advice in their operator’smanuals.)

Conway, Steve, Timber CuttingPractices, 2nd edition (Miller-Freeman Publications, San Francisc1978).

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o,

Erickson, S., Production FellingThrough Safety: The Game ofLogging (American PulpwoodAssociation, Washington, DC, 1994)

Faller’s and Bucker’s Handbook(Worker’s Compensation Board ofBritish Columbia, Vancouver, BC,1973).

Falling and Bucking Safety Guide(Oregon Occupational Safety andHealth Division, Salem, OR, 1992).

Safe Design and Use of ChainSaws (International Labor Office,Geneva, Switzerland, 1978).

Sarna, R.P., Chain Saw Manual(The Interstate, Danville, IL, 1979).

Soderstrom, N., Chain Saw Savvy(Morgan and Morgan, New York,NY, 1982).

World Wide WebYou can access our Educational

Materials catalog and some of ourpublications through our Web page http://wwwagcomm.ads.orst.edu/

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© 1996 Oregon State University

The Woodland Workbook is a collection of publications prepared by the Oregon StateUniversity Extension Service specifically for owners and managers of private, nonintrial woodlands. The Workbook is organized into separate sections, containing infortion of long-range and day-to-day value for anyone interested in wise managementconservation, and use of woodland properties. It’s available in a 3-ring binder withtabbed dividers for each section.

For information about how to order, and for a current list of titles and prices, inquirethe office of the OSU Extension Service that serves your county.

This publication was produced and distributed in furtherance of the Acts of CongresMay 8 and June 30, 1914. Extension work is a cooperative program of Oregon StatUniversity, the U.S. Department of Agriculture, and Oregon counties.

Oregon State University Extension Service offers educational programs, activities, materials—without regard to race, color, religion, sex, sexual orientation, nationalorigin, age, marital status, disability, and disabled veteran or Vietnam-era veteranstatus—as required by Title VI of the Civil Rights Act of 1964, Title IX of the EducatiAmendments of 1972, and Section 504 of the Rehabilitation Act of 1973. Oregon SUniversity Extension Service is an Equal Opportunity Employer.