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Explore the various methods of primary wood transportation, covering skidding, forwarding, and yarding processes in the forestry industry. Understand the equipment, operational elements, and costs involved in wood transportation within forests.
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Primary Transportation “WOODS TURNS”Skidding, Forwarding, YardingFOR 420Jan 25, 2002James Hart
THIS WEEK’S TOPIC -PRIMARY TRANSPORT“TURNS IN THE WOODS” PRIMARY TRANSPORT SECONDAYTRANSPORT “TURN” = ? LOADING • FELLING • MANUAL • MACHINE • LIMBING • TOPPING • MEASURING & BUCKING • BUNCHING S T O R A G E ROAD TRANSPORT SKIDDING, YARDING, FORWARDING MILL UNLOADING
“TURN” WORK ELEMENTS RETURN - starts at landing, empty travel on trail, BUNCHING (ASSEMBLING, ATTACHING) - starts when equipment leaves road, ends when starts to landing SKIDDING - starts when loaded equipment is traveling on recognized skid trail, ends at landing LANDING (DROPPING, UNLOADING) - arrival, dropping load, unhooking, piling, sorting, etc DELAYS (ANYWHERE DURING TURN) - UNPRODUCTIVE - no contribution to productivity of system e.g. stuck PRODUCTIVE - e.g. required maintenance, trail building
KINDS OF PRIMARY TRANSPORT • 1. DRAFT ANIMALS (pre 1900 to present) • 2. CRAWLER TRACTOR SKIDDERS (1900-1960s) • FIRST MACHINES USED FOR SKIDDING - PNW • DRAWBAR TO ARCHES • 3. 4-WHEEL TRACTOR SKIDDERS (1900 - present) • FASTER AND FOR SMALLER TIMBER • GRAPPLE REPLACES CHOKER CABLE SKIDDING • 4. FORWARDERS (1970s - PRESENT) • REPLACING SINGLE AXLE BOBTAIL TRUCKS IN WOODS • REPLACING PALLET SYSTEMS IN THE WOODS • 5. CABLE SYSTEMS (pre crawler to present) • SEVERAL DIFFERENT SYSTEMS • REPLACED CRAWLERS TO AVOID SOIL DAMAGE • 6. AERIAL SYSTEMS (relatively recent) • BALLOON - PROVIDES LIFT AND CABLE CONTROLLED • HELICOPTER - FAST AND EXPENSIVE
DRAFT ANIMAL SKIDDING • OXEN • HORSES • BIGWHEEL • OR ~35 • Ca ~2 • AL ~50 horses & mules
HORSE SKIDDING OPERATIONS • AN OREGON EXAMPLE: • 35.5 ac thinning from below in fir-pine, 10-38” DBH, mean 14”, • 3 men, 5 Belgians, log truck with loader • 2277 trees, 80% single log skidding, mostly downslope • largest team of 2 skid was 32” 12’ 6000 lb. • 380’ mean skid distance, 935’ max, avoid 100’ up 10+ % slopes • ADVANTAGES • less capital investment, easier to move into area • only need 5-6’ space (not 10-12 like machines), leaves higher density • light damage to soil, residual stand and regeneration • DISADVANTAGES • skidders are ~2.5 X faster, take longer to log an area • cannot log large (>24”) trees, cannot skid > ~100’ up 10% slope • not many horse loggers, cannot work rocky ground
CRAWLER TRACTOR EQUIPMENT • HISTORIC 40s to 60s, then faster wheel skidders developed • WINCHES, CABLES, CHOKERS • advantage when stuck • DRAWBAR SKIDDINGcan decrease power needs 17 percent by elevating butt of log 5 1/2 feet • ARCH SKIDDING • detached • integral • OPERABLE ON SLOPES TO 60%but - erosion and soil damage concern • 300 FT -TYPICAL SKID DISTANCE • MULTI-PURPOSE MACHINES very versatile, road construction, skidding
CRAWLER TRACTOR OPERATIONS • ADVANTAGES • VERY STABLE • HIGH DRAWBAR PULL • LOW GROUND RESISTANCE • MULTI-PURPOSE e.g. ROAD CONSTRUCTION • DISADVANTAGES • SLOW 3 mph • LIMITED TO SHORT SKIDDING DISTANCES400-600’ GOOD DISTANCE FOR CRAWLER SKIDDING • HIGHER COST PER TURN, LOAD, $/CCF
WHEEL TRACTOR SKIDDER EQUIPMENT • DEVELOPED in 60s faster, more maneuverable, better on rough trails & in woods • RUBBER TIRED, ARTICULATED • FRONT BLADED • CABLES replaced by GRAPPLES • FIXED/STATIC ARCH • SWINGING BOOM 180deg • REACHING BOOM (2 cylinders) • MORE COMPUTERIZED, TRACKED, LEGGED????
GRAPPLE • HINGED SET OF JAWS - OPENED AND CLOSED HYDRAULICALLY • TYPES: • 180 degree SWINGING BOOM, • VERTICALLY MOVING, NON-SWINGING BOOM • RIGID/STATIC BOOM • ADVANTAGES • LOADING & UNLOADING QUICKER, NO CHOKER SETTER • SAFER • LESS SKIDDER MANEUVERING • DISADVANTAGES • MAY HAVE TO PRE-BUNCH • HAVE TO DROP LOAD IF STUCK • BE ADVISED THE HYDRAULIC FLUID GETS HOT AND CAN BURN YOU!
WHEEL SKIDDING OPERATIONS • EXAMPLE TIMES FOR WORK ELEMENTS • RETURN 1-5 MINUTES ON SKID TRAILS =f (DISTANCE, SPEED) • BUNCHING 2-45 MINUTES OFF-TRAIL =f (# PIECES, OBSTRUCTIONS) • SKIDDING 2-10 MINUTES ON TRAIL = f (DIST., TERRAIN, OBSTR.) • LANDING 1-3 MINUTES DROPPING, CHOKER REMOVING, PILING • DELAYS 0 MIN. & UP HANGS, STUCK, ROAD BDG, MAINT. • TOTAL 6-63+ MINUTES • ADVANTAGES • FASTER, BETTER AT BUNCHING TREES/LOGS • 1/4 MILE OPTIMUM SKID DISTANCE, 1/2 COMMON, UP TO 1 MILE • DISADVANTAGES • CANNOT DROP AND RE-WINCH LOAD WHEN STUCK • MORE ROLLING RESISTANCE • TIRES COSTLY ~$3000 (in mid 70s)
IMPORTANT FACTORS TO CONSIDER • STEEP SLOPES- higher road costs, more travel distance • ROAD DENSITY - more roads ==> less skidding distance • SKIDDING DISTANCE - • BRUSH, RESIDUAL TREES - • OBSTACLES- WET SOIL, DRY SANDS, STONY SOILS - • THREATENED & ENDANGERED SPECIES -
COST PER CUNIT (100 cubic foot) ARE MINIMIZED AT AN OPTIMUM SKIDDING DISTANCE COSTS PER CUNIT (100 cubic feet) INCREASES DRASTICALLY WITH SMALL PIECE SIZE SKIDDING COST RELATIONSHIPS
SKIDDING HANG-UPS ROLL METHOD of working around a HANG-UP JUMP METHOD of working around a HANG-UP KICK METHOD of working around a HANG-UP VARIATION OF KICK METHOD of working around a HANG-UP
FORWARDER EQUIPMENT • WOODS MACHINES, USUALLY RUBBER TIRED, WITH A STAKE BED TO HOLD RELATIVELY SHORT LOGS OR PULPWOOD BOLTS • USUALLY WITH A KNUCKLE BOOM LOADER • 2.1 X FASTER THAN A CRAWLER AND DRAY SYSTEM • REPLACING SINGLE AXLE TRUCKS WITH LOADERS IN THE WOODS • REPLACING PALLET SYSTEMS IN THE WOODS UP TO 60 % SLOPES
FORWARDER TRANSPORT SYSTEMS • ADVANTAGES • INSURES FULL PAYLOADS • ALLOWS LONGER SKIDDING/ HAULING DISTANCES (UP TO A MILE) • LESS DAMAGE TO RESIDUAL TREE • SUITED TO THINNING & SMALLER PIECES • NAVIGATE STEEPER TERRAIN THAN SKIDDERS • DISADVANTAGES • HIGHER CAPITAL, REQUIRE PRE-BUNCHING • LIMITED TO ~ 20 FOOT LENGTHS, OR BOLTS • CANNOT INTEGRATE SAWLOG TIMBER • HIGHER COST PER CUNIT • LESS VERSATILE THAN SKIDDERS • HIGH MAINTENANCE ON LOADER
SKIDDING PATTERNS PARALLEL SUNBURST CLOVERLEAF
TRAFFICABILITY & SOIL DAMAGE • POWER REQUIREMENTS INCREASE FOR EVERY INCH OF SOIL PENETRATION • HOW ARE SOIL CHARACTERISTICS RELATED TO EQUIPMENT EFFICIENCY AND COST? • CAN WE USE 20-50 TON HARVESTING MACHINES WITHOUT COMPACTING SOILS? HIGHER COSTS, LOWER PRODUCTION
Critical Path Method (CPM) & Program Evaluation Review Technique (PERT) Scheduling • THE EXISTENCE OF A LARGE NUMBER OF POSSIBLE EQUIPMENT AND ACTIVITY COMBINATIONS WITHIN A HARVESTING SYSTEM MEANS PLANNING IS ESSENTIAL • A LOGGING SYSTEM SHOULD BE DESIGNED SO THAT MEN, MACHINES AND LOGS MOVE TO MAXIMIZE VALUE AND PROFIT • VARIABLES TO CONSIDER ARE MANY • LABOR SKILLS, CAPITAL INVESTMENTS, ROADS, BRIDGES, • SIZE OF TIMBER, VOLUME PER STEM, LIMBINESS, UNDERBRUSH, • STEMS PER ACRE, VOLUME PER ACRE, • SKIDDING DISTANCE, HAUL DISTANCES, EQUIPMENT SPEED, • TERRAIN CHARACTERISTICS, SOIL, WEATHER, • PRIMARY PRODUCT, • OTHERS • OPERATIONS ANALYSIS, MANAGEMENT TECHNIQUES
APPROXIMATE OPTIMUM DISTANCES AND SLOPES FOR LOGGING SYSTEMS HORSES? 0-10%, 200-400’ >10%, 100’ ENVIRONMENTAL IMPACTS? EROSION / SEDIMENTATION LONG-TERM PRODUCTIVITY LOSS HIGH STREAM TEMPERATURES SPECIES HABITAT LOSS
VIDEOS TO SHOW • JOHN DEERE CORRIDOR THINNING VIDEOS • SHOW CHAINSAW CUTTING SYSTEM • START AT ____ LF FOR ___ MINUTES • SHOW SKIDDER SYSTEM • START AT ____ LF FOR ___ MINUTES • SHOW FELLER BUNCHER SYSTEM • START AT ____ LF FOR ___ MINUTES • JAMMER YARDING VIDEO • START AT ____ LF FOR ___ MINUTES
SOIL MECHANICS MAXIMUM DENSITY DRY DENSITY • CLAYEY SOILS ARE SLIPPERY WHEN WET • SANDY SOILS HAVE POOR TRACTION WHEN DRY • LOAMY SOILS ARE MOST TRAFFICABLE WHEN DRY • LOAMY SOILS COMPACT THE MOST WHEN MOIST • LOAMY SOILS RUT AND PUDDLE WHEN WET • COURSE FRAGMENTS ABOVE ~ 35% INCREASE TRAFFICABILITY SO WET IT WILL NOT COMPACT TOO DRY TO COMPACT OPTIMUM MOISTURE CONTENT 10 5 15 20 0 SOIL MOISTURE CONTENT % 5 5 5