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Felling, Bunching, Limbing, Topping &

Bucking Systems

FOR 420 (Harvesting)Jan __, 2001

James Hart

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SUBSYSTEM FOR STUDY

• “TREES TO WOOD ELEMENTS”

• WOODS “TURNS” - PRIMARY TRANSPORT

• LOADING

• ROAD HAULING - SECONDARY TRANSPORT

• STORAGE

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THIS WEEK’S TOPIC - “TREES TO WOOD ELEMENTS”

PRIMARY TRANSPORT

SECONDAYTRANSPORT

“TURN” = ?

LOADING

ROAD TRANSPORT

SKIDDING, YARDING, FORWARDING

• FELLING– MANUAL

– MACHINE

• LIMBING

• MEASURING

• TOPPING & BUCKING

• BUNCHING

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FORESTERS PERSPECTIVES• OBJECTIVES OF LAND-OWNER

– SELL WOOD ELEMENTS ---> FOR PROFIT

– EFFICIENT LOGGING SYSTEM TO CONTROL COSTS ---> MORE PROFIT

– CONTROLLED LOGGING ---> BETTER LAND AND FUTURE STAND VALUES

PROFIT <--------- optimum balance ---------> LAND VALUES

• UTILIZE LOGGING FOR SILVICULTURAL MANAGEMENT [OF TIMBER +]– REMOVAL OF RESIDUALS

[EQUIPMENT ACCESS, FIRE CONTROL, AESTHETICS, INSECT/DISEASE CONTROL]

– SALVAGE - CLEANING UP MESSES[WILDFIRES, ICE STORMS, WIND STORMS]

– COMPETITION CONTROL[THINNING, SPECIES SANITATION, SITE PREPARATION FOR NEXT CROP]

– CONVERSION OF TYPE

• CONTROL LOGGING FOR ECOLOGICAL / HYDROLOGICAL PURPOSES– BIODIVDRSITYAND WILDLIFE HABITAT MANAGEMENT

– AESTHETICS MANAGEMENT

– WETLAND PROTECTION

– STREAM BANK PROTECTION

– EROSION CONTROL

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FELLING CONCEPTS

• TREE CONSIDERATIONS [SIZES, WEIGHTS, VALUES, BRITTLENESS]

• PRIMARY AND SECONDARY LEAN [DOWN-SLOPE, PREVAILING WINDS]

• NATURAL LAY

• CURRENT WIND EFFECTS

• DAMAGE& WOOD LOSSES [DISEASE, CULL, BREAKAGE]

• DIRECTIONAL FALLING - GETTING AN UNNATURAL LAY [ HINGES, WEDGES, JACKS, CABLING, BIG MACHINES]

• MANUAL UNDERCUTS, SIDECUTS & BACKCUTS

• MECHANICAL FELLING [SHEARS, SAWS]

• TERRAIN CONSIDERATIONS

• SAFETY CONSIDERATIONS

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MANUAL FELLING - HISTORICAL PERSPECTIVES• BIGGER TREES - manual, hand tools, draft animals

• EQUIPMENT ADAPTION & DEVELOPMENT

• HIGH VALUE TREES - good technique to minimize damage

• SMALLER TREES - lower values, higher utilization

• COST/VALUE CONSIDERATIONS

• TERRAIN CONSIDERATIONS

• SAFETY CONSIDERATIONS http://www.garden-aids.co.nz/safety.html#basic

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WORK ELEMENT DESCRIPTIONS & VALUE LOSSES

• THE FIRST SEQUENTIAL STEPS IN TIMBER HARVESTING ARE FELLING, LIMBING, MEASIRING, TOPPING, & BUCKINGSTANDING TIMBER HAS A POTENTIAL VALUE; ITS ACTUAL VALUE IS DETERMINED BY HOW IT IS CONVERTED INTO THE FINAL PRODUCT

• FELLING - SEVERING A TREE AT THE STUMP

• LIMBING - SEVERING NON-MERCHANTABLE PORTIONS OFF THE SIDES OF THE STEM

• TOPPING - SEVERING THE NON-MERCHANTABLE APEX OFF THE TREE

• BUCKING - CUTTING A FELLED TREE INTO SHORTER SECTIONS

• MEASUREING IS NECESSARY FOR EFFICIENT TOPPING AND BUCKING

• INEFFICIENT SYSTEMS MAY RESULT IN VERY HIGH LOSSES– POOR FELLING ALONE COULD HAVE UP TO 40% WOOD LOSSES DUE TO BREAKAGE

AND/OR HIGH STUMPS– TOPPING DIAMETER AND BUCKING LENGTH DECISIONS MUST BE MADE BASED ON

PRODUCT MARKET DEMAND, WHICH ALMOST ENTIRELY SETS THE VALUE OF WOOD FROM A TREE.

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FACTORS CAUSING LOSSES

• BREAKAGE DURING FELLING AND BUCKING

• BREAKAGE IN MIXED SPECIES STANDS

• BREAKAGE IN BRITTLE TREE SPECIES [REDWOOD, CEDAR]

• BREAKAGE IN UN-EVEN TREE SIZE STANDS

• MULTI-STORIED STANDS– LOG UNDERSTORIES , THEN RELOG OVERSTORIES

• EXCESS BREAKAGE DUE TO TREE DEFECTS– COULD EASILY BE 25%

• BLOWDOWNS - LOTS OF BREAKAGE [WIND, DAMAGE WHEN FALLING]

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TREE LEAN AND LAY• LEAN - TREES HAVE LEAN, ALMOST WITHOUT EXCEPTION

– PRIMARY LEAN & SECONDARY LEAN– USUALLY DOWNHILL ON STEEP SLOPES– OFTEN RELATED TO PREVAILING WINDS– RELATED TO WEIGHT BALANCE

• LAY - POSITION ON GROUND TREE WILL FALL TO WHEN SEVERED FROM STUMP– NATURAL LAY - WHEN SEVERING HAS NO EFFECTS ON DIRECTION– DIRECTIONAL FALL LAY - WHEN SEVERING OPERATION HAS EFFECT ON LAY

• FELLING TECHNIQUES CAN CONTROL THE LAY OF A TREE (IN THE ABSENCEE OF EXCESSIVE LEAN OR WINDS) IN ANY DIRECTION DESIRED

– MANUAL CUTTING TECHNIQUE– WEDGING– JACKING– CABELING– MACHINE FELLING

• REASONS FOR CONTROLING TREE FALL DIRECTION– TO INCREASE EFFICIENCY OF THE HARVESTING SYSTEM– TO DECREASE WOOD BREAKAGE – TO INCREASE SAFETY

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SELCTION OF LAY

• TRY TO USE NATURAL LAY

• KEEP OUT OF SURFACE WATERS AND WETLANDS

• AVOID BREAKAGE BY NOT HITTING– SURROUNDING TREES OR SNAGS– SOLID OBJECTS – UNEVEN GROUND CONTOURS

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FELLING BREAKAGE SITUATIONS

•SEE LEFT FOR DOUGLAS FIR EXAMPLES

•DUE TO CONDITIONS OF LAY AREA

•adjacent trees•adjacent snags•solid objects [stumps, rocks, down trees]•high terrain spots•low terrain spots

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BASICS OF MANUAL TREE FELLING

• “UNDERCUT” 1/4 to 1/3 OF DIAMETER

• ALIGN UNDERCUT PERPENDICULAT TO DIRECTION OF FALL

• DOWNCUT “SCARF” AT ~ 45 DEGREE ANGLE

• “BACKCUT” ~ 1-3” (or 1/10 diameter) ABOVE UNDERCUT

• LEAVE 1-2” “HINGEWOOD”

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UNDERCUTS:

A. CONVENTIONALB. HUMBOLTC. CORRECT D. INCORRECT

“SIDECUTS” ON BEECH

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VOLUME LOSSES

CONVENTIONAL vs HUMBOLT

“volume & value difference can begreat in very large trees”

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THE EFFECTIVE,BUT DANGEROUS AND NOTRECOMMENDED,“DUTCHMAN CUT”

(details not intended to be learned)

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FELLING TREES WITH SIDE LEAN• Make the scarf facing the desired

direction of fall.

Start the back cut on the leaning

side of the tree, leaving slightly

narrower hinge wood than

normal.

Put the wedge in the cut.

Continue the back cut from the

other side, allowing for wider

hinge wood, and tap the wedge

in as the cut takes place.

Drive the wedge home when the

cut is complete. The tree should

fall in the desired direction.

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8’ OF SIDE LEAN

8 FEET OFFSET OF LAY

DIRECTION OFFALLING

WHEN DIRECTIONAL FELLING AWAY FROM NATURAL LAY, IT IS NECESSARY TO ADJUST FOR AMOUNT OF SIDE LEAN

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FELLING TREES THAT ARE LEANING BACK

• Remember - wedges are limited in changing the direction of fall.

• The Wedge Method Cut the scarf as normal in the desired direction

of fall. Back cut as normal. As soon as there is sufficient solid wood, insert

the wedge or wedges in the cut and drive in as the cut progresses.

Use Jacks or cables

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MECHANICAL FELLING

• EQUIPMENT CHOICES– SHEARS

– DISC SAWS

– CHAIN SAWS

• SELECTION CRITERIA– COSTS [EQUIPMENT, INTEREST, OPERATING]

– PRODUCTION [TREES AND VOLUME PER DAY

• SOIL DAMAGE EFFECTS• WOOD DAMAGE EFFECTS

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SHEARS:

A. DOUBLE ACTION

B. SINGLE ACTION

“SAW” NOT SHOWN

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TIMBERJACK 950 FELLER BUNCHER - equipped with S586 disc-saw felling head to a maximum of 61 cm

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SHEAR DAMAGE

- VARIABLE BY SPECIES AND LOCAL CONDITIONS

- FROM A FEW INCHES

- TO 2 FEET

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•PLAN FOR OPENING UP TWO “SETS” FOR SIMULTANEOUS CUTTING BY 2 CREWS ON FLAT TERRAIN

•DIRECTIONAL FELLING TOWARD LANDING

•CUTTING WILL PROCEED TO RIGHT

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GROUP FELLING TO INCREASE SKIDDING EFFICIENCY FOR SMALL TREES

NOTE TREE BUTTS ALLIGNED FOR SKIDDER PICK-UP

DIRECTION OF SKIDDING

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COUNTER CLOCKWISE DIRECTIONAL TREE FELLING WITH TREE TOPS ALIGNED AWAY FROM LANDING FOR EFFICIENT BUTT PICK-UP BY SKIDDERS

WORK PLANNED TO PROCEED CLOCKWISE

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PLANNED DIRECTIONAL FELLING IN SETTING WITH STREAM AND ADJACENT STEEP TERRAIN

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MANUAL MEASURING AND BUCKING

• OBJECTIVES - CUTTING TO MILL SPECIFICATIONS IN THE WOODS

• NATURAL LAY AND PREDICTION OF CUTTING EFFECTS– BREAKAGE

• WINDTHROW / ROOT PLATE PROBLEMS

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4 BASIC BUCKING LAYS

TOP BIND LAYBOTTOM BIND LAY

SIDE BIND LAY DROP LAY - SLANT CUT

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NEXT WEEK’S TOPIC - PRIMARY TRANSPORT,

“TURNS” IN THE WOODSPRIMARY TRANSPORT

SECONDAYTRANSPORT

“TURN” =d ??????????FELLING, LIMBING, MEASURING, TOPPING, BUCKING

LOADING

ROAD TRANSPORT

SKIDDING, YARDING, FORWARDING

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• BUTTS TOPING TOPPING

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MECHANICAL FELLER-BUNCHER SYSTEMS

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PERT ANALYSIS

• THE EXISTANCE OF A LARGE NUMBER OF POSSIBLE COMBINATIONS WITHIN A HARVESTING SYSTEM MEANS PLANNING IS ESSENTIAL (SC82)

• A LOGING SYSTEM SHOULD BE DESIGNED SO THAT MEN, MACHINES AND LOG IMPORT ARE CORRELATED.

• VARIABLES TO CONSIDER ARE MANY[LABOR SKILLS, SIZE OF TIMBER, VOLUME PER STEM, STEMS PER ACRE, VOLUME PER ACRE, LIMBINESS, UNDERBRUSH, PRIMARY PRODUCT, SKIDDING DISTANCE, EQUIPMENT SPEED, CAPITAL INVESTMENTS,TERRAIN CHARACTERISTICS, SOIL, HAUL DISTANCES, WEATHER, OTHERS]

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