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1 Felling, Bunching, Limbing, Topping & Bucking Systems FOR 420 (Harvesting) Jan __, 2001 James Hart.

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Presentation on theme: "1 Felling, Bunching, Limbing, Topping & Bucking Systems FOR 420 (Harvesting) Jan __, 2001 James Hart."— Presentation transcript:

1 1 Felling, Bunching, Limbing, Topping & Bucking Systems FOR 420 (Harvesting) Jan __, 2001 James Hart

2 2 SUBSYSTEM FOR STUDY “TREES TO WOOD ELEMENTS” WOODS “TURNS” - PRIMARY TRANSPORT LOADING ROAD HAULING - SECONDARY TRANSPORT STORAGE

3 3 THIS WEEK’S TOPIC - “TREES TO WOOD ELEMENTS” PRIMARY TRANSPORT SECONDAY TRANSPORT “TURN” = ? LOADING ROAD TRANSPORT SKIDDING, YARDING, FORWARDING FELLING –MANUAL –MACHINE LIMBING MEASURING TOPPING & BUCKING BUNCHING

4 4 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 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

5 5 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

6 6 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

7 7 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.

8 8 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]

9 9 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

10 10 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

11 11 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

12 12 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”

13 13 UNDERCUTS: A. CONVENTIONAL B. HUMBOLT C. CORRECT D. INCORRECT “SIDECUTS” ON BEECH

14 14 VOLUME LOSSES CONVENTIONAL vs HUMBOLT “volume & value difference can be great in very large trees”

15 15 THE EFFECTIVE, BUT DANGEROUS AND NOT RECOMMENDED, “DUTCHMAN CUT” (details not intended to be learned)

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17 17 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.

18 18 8’ OF SIDE LEAN 8 FEET OFFSET OF LAY DIRECTION OF FALLING WHEN DIRECTIONAL FELLING AWAY FROM NATURAL LAY, IT IS NECESSARY TO ADJUST FOR AMOUNT OF SIDE LEAN

19 19 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

20 20 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

21 21 SHEARS: A. DOUBLE ACTION B. SINGLE ACTION “SAW” NOT SHOWN

22 22 TIMBERJACK 950 FELLER BUNCHER - equipped with S586 disc-saw felling head to a maximum of 61 cm

23 23 SHEAR DAMAGE - VARIABLE BY SPECIES AND LOCAL CONDITIONS - FROM A FEW INCHES - TO 2 FEET

24 24 PLAN FOR OPENING UP TWO “SETS” FOR SIMULTANEOUS CUTTING BY 2 CREWS ON FLAT TERRAIN DIRECTIONAL FELLING TOWARD LANDING CUTTING WILL PROCEED TO RIGHT

25 25 GROUP FELLING TO INCREASE SKIDDING EFFICIENCY FOR SMALL TREES NOTE TREE BUTTS ALLIGNED FOR SKIDDER PICK-UP DIRECTION OF SKIDDING

26 26 COUNTER CLOCKWISE DIRECTIONAL TREE FELLING WITH TREE TOPS ALIGNED AWAY FROM LANDING FOR EFFICIENT BUTT PICK- UP BY SKIDDERS WORK PLANNED TO PROCEED CLOCKWISE

27 27 PLANNED DIRECTIONAL FELLING IN SETTING WITH STREAM AND ADJACENT STEEP TERRAIN

28 28 MANUAL MEASURING AND BUCKING OBJECTIVES - CUTTING TO MILL SPECIFICATIONS IN THE WOODS NATURAL LAY AND PREDICTION OF CUTTING EFFECTS –BREAKAGE WINDTHROW / ROOT PLATE PROBLEMS

29 29 4 BASIC BUCKING LAYS TOP BIND LAY BOTTOM BIND LAY SIDE BIND LAY DROP LAY - SLANT CUT

30 30 NEXT WEEK’S TOPIC - PRIMARY TRANSPORT, “TURNS” IN THE WOODS PRIMARY TRANSPORT SECONDAY TRANSPORT “TURN” =d ?????????? FELLING, LIMBING, MEASURING, TOPPING, BUCKING LOADING ROAD TRANSPORT SKIDDING, YARDING, FORWARDING

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33 33 BUTTS TOPING TOPPING

34 34 MECHANICAL FELLER- BUNCHER SYSTEMS

35 35 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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