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Logging Terminology

This glossary includes words associated with logging, transportation, forest engineering and silviculture.

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Courtesy Carlton S. Yee, Ph.D. RPF, Emeritus Professor of Forestry, Humboldt State University Forestry Department, and the Central Oregon Community College Forestry Department.


A

Active falling area– The area within two tree-length radius of where a faller or a mechanized falling machine is operating.

Adverse (grade)-Ascending grade in the direction of travel

Aerial logging– A logging system which fully suspends the logs such as done by helicopters or balloons. Not to be confused with cable systems which use cables and supports.

Anchor– A stump or wooden, concrete, or metal device secured in the earth to hold a line securely. Also see “Deadman”.

Anchor line– A line to used to tie down a yarder to prevent tipping. Also see “Guyline”.

Arch– A framework through which a winchline from a skidder passes over and is used to suspend the leading ends of logs being dragged(skidded).

Arched skidding– Skidding logs with an arch to raise the front of the logs off the ground; as opposed to “ground skidding”.

Average yarding distance– Often abbreviated as AYD, the total yarding distance for all turns for a particular logging setting or unit divided by the total number of turns. Usually expressed as slope distance, unless otherwise stated.

B

Backcut– The final cut in felling a tree by hand, made on the side opposite the intended direction of fall, after the undercut.

Bar or blade– That part of the chainsaw upon which the cutting chain moves.

Barberchair– A vertical split in a tree, generally caused by an insufficient undercut or by neglecting to cut the sapwood on both sides of a heavy leaning tree before felling. Results in a stump which looks like a high-backed chair. Very dangerous to the faller.

Back guy– The guy line(s) behind the spar, opposite the lead of the main line or skyline in a cable logging setup. Usually applies to standing towers, rather than to swing towers.

Back spar– See “Tail spar”.

Beaver-tailing– Burying the whole bar of a chainsaw into the log or tree while cutting

Bed– The intended position in which a tree will be felled. In redwood (Sequoia sempervirens), a bed is created by a bulldozer from piled up earth and slash so as to cushion the fall of these brittle giants.

Bell– A type of choker hook that slides on the choker wire between the two knobs.

Belly– A sag in any line.

Bight– a) Any section of a line between the ends. b) A band or sag in a line under tension. c) A work area made hazardous by a line or equipment under tension.

Bind or bound– Compression created in a cut in a tree or log due to uneven terrain or contact pressure from other trees or logs. This will result in the chainsaw being caught in the log or tree.

Binder– A wire rope placed across a load on a logging truck to secure the load. AKA “wrapper”.

Blade– (a) n. The part of a bulldozer or grader which digs and pushes dirt but does not lift it. (b) v. To scrape or level a mound of dirt or area of ground with a blade. e.g. “It was necessary to blade the landing to smooth it for use.”

Blind lead– The situation on a convex slope where the line of sight from the tail block to the yarder tower’s mainline or skyline fairlead block (bull block) is obstructed. May result in hangups to the logs being yarded if ground leading rather than full suspension is being used or available.

Block– A wooden or metal case enclosing one or more pulleys used to lead a line in a specific direction, and provide with a hook, eye, or strap by which the unit may be attached to an object, such as a spar tree or anchor.
Board foot- The standard unit of measure for standing timber, logs and lumber in the United States. A board foot is represented by a board one foot wide, one foot long and one inch thick. A unit in board feet is usually expressed in 1,000 board feet or MBF. For example, 28,500 board feet is expressed as 28.5 MBF. The number of MBF in a log or stand of timber is a function of the “log rule” used in the local area. Different log rules will yield different estimates of MBF based on the log rule’s assumptions.

Bole– The trunk of a tree, especially the merchantable or useful portion.

Boom– A raft of logs or a string of logs chained together, end to end, used to hold floating logs. A means of log storage or transportation.

Breaking Strength– The greatest load that a wire rope or other material can withstand before breaking. Also known as the “ultimate strength’. Compare to “working strength”.

Break out– To get a log out of a hang-up or its initial lay on the ground.

Brow-log– A log placed parallel to the roadway at a landing or dump. Sometimes also called a bumper-log.

Brush monkey– Usually the newest member of the cable yarding crew, usually assigned the worst or least desirable tasks, an entry-level logger.

Brush-out or swamp-out– To clean out brush or other material around the base of trees to be felled or logs to be bucked so as to provide safe footing, prevent saw kickbacks, and to provide an escape path for the faller.

Buck– To saw felled trees into log lengths. Note: In some two person felling operations, one member may fall the tree and the other may limb and buck it. The second person is often called a “bucker”. Usually the two members interchange the duties throughout the work day.

Buckskin– A log or tree with the bark fallen off.

Buffer strip– A strip of timber left along a watercourse or lake for environmental reasons, such as shade, future large woody debris recruitment, sediment filtration, and other benefits. Usually excludes equipment entry, but often permits the logging of some trees. May also be called a Watercourse And Lake Protection Zone (WLPZ, in CA), Riparian Management Zone (in OR), Stream Protection Zone, or other terms depending on the region and organization.

Bullbuck– The foreman of a cutting crew.

Bull block– The mainline lead block in high lead logging.

Bulldozer-See “Cat”, AKA “dozer”

Bull hook– A hook for attaching chokers to a line. AKA “butthook” in highlead logging.

Bump knots– To cut knots off of a log. The worker on the landing who trims up logs and cuts off missed limbs and branch stubs is often called a “knot bumper”.

Bunch– To assemble several logs together to form a load for subsequent skidding or yarding.

Bunk– a) A crossbeam on a truck on which the logs rest. b) To place the empty trailer of a logging truck on the tractor unit’s bunk for the trip back to the landing

Bunk log– Any log resting on the bunk of a truck.

Busheler– A logger or contractor who works at piece rates. More commonly called a “Gypo” in the western U.S. Usually used to refer to independent loggers versus company hired loggers.

Butt log– The first and biggest log from a tree.

Butt hook– The heavy hook on the butt rigging to which the chokers are attached in high-lead cable logging.

Butt rigging– A system of swivels and clevises which connect the haulback and mainline together and to which butt hooks are fastened. An essential part of the high lead, cable logging system.

C

Cable– Actually more correctly termed a wire rope (see Wire rope).

Cable logging– A yarding system employing winches and cables from a fixed position (usually a yarder and tower of some sort).

Cableway– The location or pathway of a cable suspended between elevated supports so as to constitute a track along which log carriages can be pulled.

Carriage– A load-carrying device from which logs are suspended and which rides back and forth along the skyline on sheaves for yarding. Also called the “skyline carriage”.
Cat face- Deformed tree trunk surface usually caused by fire, disease or rot.

Catenary curve– The shape assumed by a cable suspended freely between two points.

Cat– Often short for Caterpillar tractor, or any other brand of bulldozer-type tractor. May refer to a skidding tractor or a earthmoving bulldozer.

Cat road– A path created by tractors for skidding logs, or any crude roadway or path cut by a bulldozer. AKA “skid trail” or “skidroad”.

Cat skinner– The person who operates a cat.

Caulks– Short spikes driven or screwed into the bottom of loggers’ boots to give footing while walking on logs or wood. Calked boots are considered essential for woods personnel in many parts of North America, especially where cable yarding is done. Also spelled “calks” or “corks”.

Chain and board– A graphical method of calculating skyline load path and deflection by pinning a length of light chain (e.g.: lamp pull chain) to a drawing board covered with grided cross-section paper on which cableway ground profiles have been drawn to scale. Methodology is described in the Publications and References.

Chance– A logging show or operation

Change roads-To move rigging and running lines to progressively yard logs from the next area in the felled and bucked timber. AKA “line change”.

Chase– To unhook chokers from the logs at the landing. The person doing this is called a “chaser”.

Chip– to mechanically reduce logs or whole trees to small pieces for fuel, pulp, or chipboard manufacture. The equipment is called a chipper. See “clean chips” and “dirty chips”. May also be called “in-the-woods” chipping.

Choker– A short (usually less than 20 feet) noose of wire rope for hauling logs.

Choker setter- the person who puts a choker around a log and attaches it to the skidding or yarding equipment.

Chord– A straight line between skyline support points.

Chord slope– The slope, in percent or degrees, of the skyline chord.

Chute– The area at the landing where logs are landed on a high-lead or cable logging operation.

Clean chips– Wood chips for pulp manufacture without any bark included, requires a chipper with a debarker.

Clambunk– A specialized forwarder designed to skid tree-length logs.

Clamped carriage– A skyline carriage which clamps to the skyline when stopped and picking up logs. Clamped carriages produce more severe loading condition on the skyline than do unclamped carriages.
Clevis- See “shackle”.

Climbing spurs– Irons with sharp side spurs, strapped to the legs at the ankle and below the knee. Used by riggers to climb trees for topping and rigging. Part of this geat is is a climbing rope and belt. AKA “spurs”.

Closing line– A line used to close a grapple or tongs.

Cold deck– A stack of logs left for later transportation (in the woods), or a deck of logs at the mill for winter use.

Continuous strip landing– A section of roadway used as a landing in a cable logging operation where the yarder, loader, and logging truck are in a line along the road. The operation often moves down the road as logging progresses. The opposite would be a “spot landing”.

Contour felling– Timber felled parallel to ground contour lines on the slope.

Cord– A unit of wood volume equal to 128 cubic foot of stacked wood. Commonly used for smaller timber utilized for firewood or pulping.

Corner block– A block off to the side which is used to guide the haulback line. AKA “haulback block”.

Corridor– see “cableway”.

Counterweight– Extra weight added to the rear of any mobile equipment to increase lifting capacity.

Counterweight clearance– The distance from the counterweight to any stationary object. Minimum clearance is usually set by various OSHA-type rules governing the jurisdiction logging is occuringin.

Crawler– Any track propelled machine in the woods.

Crossing the lead– Felling a tree at an angle across the established felling pattern.

Crummy– A vehicle used for crew transportation to and from the woods.

Cull– Any log or tree which is unmerchantable due to size, defect, or damage. May also be used to describe something which is generally worthless, e.g. ” As a choker setter, he was a cull.”

Cunit– A unit of wood volume measuring 100 cubic feet . More commonly used for estimating smaller timber to be utilized for pulping or firewood. However, in the 1990s, the U.S. Forest Service began to sell all timber based on the cubic foot volume rather than MBF.

Cut-to-length harvester (CTL)– A self-propelled tracked or wheeled harvesting machine, designed to fell, limb, and buck a tree into logs, usually 20 feet or less in length. Most commonly the harvesting head is mounted to an articulating arm. Not to be confused with a full-tree length harvester or feller-buncher. Most commonly CTL harvesters work with forwarders which transport the bunched log piles to the landing.

Cut, rigging – AKA “weakening cut”. A tree lying in such a position that a normal bucking cut can not be made safely. In order to facilitate yarding or skidding, the faller will make partial bucking cuts from a safe position, perhaps two log lengths apart.

Cut slope ratio (CSR)– The slope of a cut bank on the road or landing. Usually expressed as a ratio of X:1, where X is the number of feet run per one foot of rise. Hence a CSR of 2:1 is flatter than one of 1:1. Often of importance when a swing yarder is setup on a road and the road is used as the landing.

Cutting Pattern– The visible pattern to which trees are felled during a cutting operation.

Cutting unit– An area of timber designated for harvest. Several cutting units may make a timber harvest plan or a timber sale.

Cycle– A complete set of operations or tasks that is repeated. Also see “turn”.

D

Dangling head– A type of harvesting head, usually used on a CTL harvester, with a wrist-like action and attachment to the harvester boom. Also called a “single-grip harvesting head” and can rotate in all three axes.

Deadman– A completely buried anchor, often a log, used where no suitable stumps exist for anchoring.

Deck– A stack of logs, or used as a verb, to stack logs.

Deflection– The vertical distance between the chord and skyline, usually measured at midspan and expressed as a percentage of the span. Also known as “sag”.

Delimber– Landing-based piece of equipment used to limb trees brought in unlimbed, usually cut with full tree length harvesters. May be of the stroke delimber type or pull-through delimber model.

Depreciation– The annual reduction in value of a piece of equipment or capital asset due to wear and tear or obsolescence.

Directional felling– Felling trees according to a predetermined pattern or lay on the ground. It may involve jacking or pulling of trees.

Dogs– Pointed teeth located between the chainsaw bar and motor. Used in falling or bucking to pivot saw and to maintain position while cutting.

Dirty Chips– Wood chips which include bark and some leaves or needles, as would be used in a fuel or biomass operation. No debarker step required before chipping.

Domino Falling– Placing undercuts and backcuts in a series of trees, then pushing them with another tree. Domino falling is an unsafe and dangerous practice.

Drawbar– A fixed or hinged tow bar extending out the rear of a tractor.

Drop line– The line from a carriage to which chokers are set.

Drum– A spool around which a cable is wound.

Dump– An area where logs are off-loaded on land or into water.

Dutchman– A flat area produced when two horizontal cuts of the undercut do not meet at a point, thereby leaving a portion of an undercut not removed. An unsafe falling practice.

E

Efficiency factor– A ratio corresponding to the average percentage of total time that productive work is being performed by personnel or equipment.

Efficiency hour– Identical to “Efficiency factor”, but expressed in terms of time, such as a 50 minute hour (I.e.-50 minutes of productive time per 60 minute hour).

Equalizing block– A block used to distribute load as in connecting anchor cables to heel lines in a multiple anchor system.

Escape route– A planned and brushed out route used by fallers to make their way into the clear when the backcut is completed and the tree begins to fall.

Excavator– A hydraulically operated, boom equipped digging machine, most commonly track mounted, which can build full-benched logging roads with little to no sidecast loss.

Export log– A log that meets the species, ring count per inch, diameter, taper, and knot size requirements for export to countries such as Japan.

Extension– A line added to another to increase its length.

External yarding distance (EYD)– The slope distance from the landing to the furthest reachable point within the cutting unit’s boundary.

Extra-improved plow steel (EIPS)– A standard grade of wire rope with the highest breaking strength, 15% higher than Improved Plow Steel (IPS) grade.

Eye– A loop at the end of a wire rope secured by splicing or press fitted.

F

Factor of Safety– The ratio of the breaking strength of a line or material to the applied load.

Fairlead– A device that consists of pulleys or rollers arranged to permit reeling in a cable from any direction; commonly found atop a standing tower yarder.

Fall– See “fell”. Note: “fall” and “faller” are often used interchangeably with “fell” and “feller”.

Faller– A logger who fells timber; usually restricted to people doing hand felling, not to operators of tree harvesters. AKA “Chopper”, “Feller”.

Fan-shaped setting– A logging unit with yarding roads radiating from a common landing or common tailhold. Most commonly seen in cable units.

Favorable (grade)– Descending grade in the direction of travel. Opposite of adverse.

Fell-To cut down trees. Also “fall”.

Feller-buncher– See “Full-tree length harvester“.

Ferrule– A metal sleeve or collar swaged to the end of a wire rope to make a terminal knob.

Fixed-grip harvesting head– The harvesting head type found on feller-bunchers. Usually fixed to the boom or front of the harvester and does not rotate around all three axes.

Fiber core– The central member of a wire rope, made of woven strands of synthetic or natural fibers such as sisal, jute or cotton.

Fire watch– A look-out posted after the logging shift to watch for any fires starting from the day’s activities.

Fixed cost– A cost item for a piece of equipment which does not vary in the aggregate or total. In other words, the production or utilization of the equipment does not change the total cost. e.g. interest, insurance, annual depreciation. However, the per unit cost may vary inversly as utilization increases.

Fly– To carry logs completely off of the ground on a skyline.

Flyer– AKA Shotgun. A two-drum, live skyline yarding system in which the carriage moves down the skyline by gravity, is lowered to attach logs, then raised and pulled to the landing by the main line.

FOPS– a) falling object protective structure which protects equipment operators from falling objects, such as trees, limbs, or rocks. When the FOPS also is equipped with windows, or screens to prevent objects from “spearing” the operator, it is secure from foreign-object penetration also. b) FOPS may also stand for fall-over protective structure, similar to ROPS and usually the same structure.

Forwarder– A special vehicle with a cradle or bunk or trailer used to forward logs. Usually it is equipped with its own log loader device and may be tracked or wheeled. Most commonly works with a CTL harvester.

Forwarding– The act of carrying logs off the ground from stump to landing.

Front-end loader– A loader with a bucket or fork hinged to lifting arms which loads or digs entirely at the front end. A common example in the woods is the CAT 966 series of loaders.

Full-tree length harvester– A machine with a fixed-grip harvesting head which can grasp, cut, lift, swing and bunch trees for yarding. Usually this machine does not limb or buck to log lengths as a “cut-to-length” harvester can do. Also know as a “feller buncher”.

G

Gantry tower– The short tower on a modern swing yarder, located just ot the rear of the leaning yarder tower, used to accomodate the walking guy lines and lines to raise and lower the boom of a yarding crane.

Grabinski– A modified highlead yarding system where the butt rigging is attached to a riding block which rolls on the haulback line, providing limited deflection and suspension with a 2-drum yarder. Also nicknamed the “Polish skyline”.

Grade resistance(assistance)– The force of gravity resisting (assisting)movement on an adverse (favorable) grade.

Grapple– A hinged set of jaws capable of being opened and closed, used to grip logs during yarding or loading. Can also be attached to swing or nonswinging grapple skidder.

Grapple skidder– A skidder equipped with a grapple to handle logs; used in place of chokers

Grapple yarding– Cable yarding with grapples instead of chokers.

Gravity logging– Any cable system that depends on the force of gravity for the downhill travel of the carriage, I.e.-no haulback line is necessary. See “shotgun“.

Ground lead– A method of, or condition in, cable logging in which the pull of the hauling line is parallel to the ground, i.e.-no deflection is provided and hence usually no to little lift.

Ground skidding– Pulling logs parallel to the ground without using an arch to raise the forward end.

Grouser- The raised steel strip the length of a crawler pad to provide traction.

Guy– Lines from a yarding machine to substantial anchors for support against yarding forces.

Guyline– A wire rope used as a guy. Also see “Anchor line“.

Gypo– A logger or contractor who works at piece rates. Also called a “Busheler”. Usually used to refer to independent loggers versus company hired loggers.

H

Hangup- a) A log stuck behind a tree, stump, or other obstruction during yarding, preventing its forward movement. b) To fall a tree so that it lodges in a second tree rather than falling to the ground. c) To get the saw bar caught in the kerf while bucking a log.

Harvesting– A loose term for the removal of trees from the forest, for product utilization.

Harvesting head– A device on Cut To Length and Full Tree Logging machines which automates the harvesting operation and combines several or all steps into this one device, such as felling, limbing, bucking, and bunching.

Haulback block– A block in a cable yarding system used to guide the haulback line. In some systems, may also be called a tailblock.

Haulback line– A wire rope used to pull the mainline with carriage or butt rigging with chokers back to the timber for the next turn.

Hayline or haywire– a) A light cable, usually 3/8 inch or less in diameter, used to string heavier lines, AKA “Strawline”. b) Any unsafe or slipshod work procedure.

Hayrack– A type of log hauling trailer with multiple stakes to contain many small trees in the load.

Heel boom– A loader with a grapple or tongs at the end of a boom or arm which forces one end of the log being loaded against the underside of the boom to steady it and raise the front end of the log. Almost exclusively hydraulically operated today (but example of cable-operated heel booms can still be seen in some areas). AKA “hydraulic loader” or a “juicer”.

Herringbone felling– Timber felled in a herringbone pattern towards the center of the yarding road.

Highball– Go ahead fast. Do the work at a hurried pace. AKA “balls to the wall”.

High climber– A logger who climbs trees to top them or rig them with blocks for cable yarding. Also known simply as a “climber” or “tree climber”. Although few, if any, landing spar trees are rigged any more (portable towers having replaced them), there is still a need for climbing trees to rig them for tail spars or to set lines for directional tree pulling during felling.

Highlead– A cable yarding system in which lead blocks are hung on a spar or tower to provide lift to the front end of the logs. Only requires a 2-drum yarder which may provide some limited deflection to the logs. Not a “skyline” cable system.

Highway log truck– A log truck designed to haul a load not exceeding legal highway limits (e.g. weight, width, height, length); parameters will vary by state in the U.S.A.

Hoe chucking– AKA “Shovel logging“. The use of a hydraulic loader to move and arrange logs into decks in the cutting area or to roads and landings.

Hog fuel– Coarse wood chips and bark produced to be burned as fuel. Also known as “biomass chips”.

Holding wood– Hinge of wood left uncut between the back of the undercut and the backcut.

Hook– a) n. A curved member used to catch, hold, or pull something. b)v. To attach chokers to logs in the brush.

Hooktender– The working foreman in charge of a yarding crew.

Hoot owl– A logging operation limited to the early morning hours when fire danger later in the day will require a cessation of operations.

Horse Logging– Logging with large draft horses. Very specialized form of logging where the main advantage is low stand impact in selection logging.

Hot deck– A pile of logs from which logs are hauled as soon as they are yarded. AKA “hot loading” or “to hot log”.

I

Improved plow steel– The standard grade of wire rope with a breaking strength 15% less than EIPS. See “Extra improved plow steel”.

Independent wire rope core (IWRC)– The central member of a wire rope, consisting of a single small wire rope.

Inhaul– The portion of a cable yarding cycle where a turn of logs is brought to the landing.

Interlock yarder– A yarder which incorporates a means of coupling the main and haulback drums to recirculate the horsepower required to maintain running line tensions.

Intermediate support– A spar tree or cable sling located between the headspar or tower and the tailspar to which a tree jack or “J-bar” is attached to support a multispan skyline.

J

Jack– a) A mechanical or hydraulic device used to tip over an undercut tree in a desired direction, usually counter to the natural lean of the tree. See “Directional felling“. b) A hanger to support a skyline or other line. AKA “J-bar”.

Jackpot– A pile of haphazardly felled trees.

Jagger– A broken strand projecting out of a worn wire rope.

Jammer– A light weight, ground lead yarder using tongs and usually mounted on a truck with a spar and boom. Usually relatively inexpensive and equipped with a single drum. It may be used for both yarding and loading.

J-bar– See “Jack” (b).

Jill-poke– A supported straight log, pole, sapling, or bar that strikes an object at an angle, either spearing the object or pushing it a side. Cat skinners and skidder operators must be especially careful of jill-pokes while skidding. ROPS and FOPS are designed to protect the operator from Jill-pokes, among other hazards.

K

Kerf– The width of a saw’s cut.

Kickback– a) When a chainsaw’s bar rebounds upward off the log being sawed, often in a uncontrolled manner and out of the faller’s control. b) When a tree being felled slips backward off the stump toward the faller.

Kip– A unit of weight or force equal to 1,000 pounds; “thousand (kilo) in pounds”.

Knob– AKA Ferrule. A metal sleeve or collar swaged to the end of a wire rope to make a terminal knob.

Knuckleboom– A hydraulically operated loading boom whose mechanical action imitates the human arm. Common on “forwarders”.

L

Land– To place logs into a landing during yarding or skidding operations.

Landing– A place where logs are collected prior to further transportation. See “Spot landing” and “Continuous strip landing

Landing man– Worker who bucks, limbs, and trims log ends, unhooks chokers and assists in hooking up trailers to logging trucks. Also see “Chaser“.

Lang lay– A type of wire rope more suitable for running through multiple sheaves. The wires making up the strands run the same direction as the strands themselves, giving greater flexibility. Compare to Regular Lay.

Lateral yarding– Any movement of logs toward the centerline of a yarding road.

Lateral yarding distance– The maximum distance perpendicular to each side of a skyline road within which logs can be attached for yarding.

Lay– a) The position of a felled tree on the ground. b) the direction that strands of a wire rope are spirally wound around the core.

Layout– a) a logging plan including units and roads. b) The position of the running lines in a cable yarding system.

Lead– a) The direction of the operating or main line(s). b) A block or series of of blocks or rollers attached to a stationary object to guide the cable by which logs are dragged. c) The established direction in which all the trees on a given strip or setting are to be felled.

Lead, square– A yarding layout where the main line make a 90° angle with the axis of the yarder frame. Usually associated with spar trees where the yarder sled or frame is separate from the spar. Term is not useful with modern portable,standing spar towers.

Lead, straight– A yarding layout where the mainline is inline with the axis of the yarder and spar frame. Usually associated with spar trees where the yarder sled or frame is separate from the spar. Term is not useful with modern portable,standing spar towers.

Lead, V– A yarding layout where the angle between the mainline and the axis of the yarder and spar frame is less than 90°. AKA “diamond lead”.Usually associated with spar trees where the yarder sled or frame is separate from the spar. Term is not useful with modern portable,standing spar towers.

Lean– The direction in which a tree or trees are leaning.

Leave strip– A strip of uncut timber left between cutting units. See “Buffer strip”.

Leave tree– A tree left standing after timber has been felled in a cutting unit. Common reasons for leave trees are for seed sources, wildlife purposes, among others.

Length of ground– Used to describe whether the ground in a unit is badly cut up and rough or smooth and uniform.

Limb– a) n. Branch of a tree. b) v. To cut branches off a tree or log.

Line change– see “Change roads“.

Line pulling– Felling trees against the lean by securing a line and pulling it over with a cat or line winch. This procedure is commonly required in stream protection areas. A form of “Directional felling“.

Line swivel– A swivel in the butt rigging or line.

Live skyline– A standing skyline that can be raised and lowered to facilitate yarding. AKA “slack skyline”.

Load– a) v. To pick up logs and to place them on a vehicle for transportation. b) n. The object(s) being hauled.

Loaded deflection– Deflection when the skyline is supporting a load of logs.

Loader– any of a variety of machines, wheel or track mounted, designed primarily to lift and load a truck, train or other mode of transportation. Load path- The arc traced by a turn oflogs along a skyline and genrally plotted graphically to determine ground clearance.

Log– a) n. Any cut section of a felled tree. b) v. To harvest timber.

Log brand– An ownership identification mark stamped into the end of a log.

Log Deck– A stack of logs, also “Deck”.

Log Dump– A central unloading area for loads of logs.

Log rule– Any of several formulae, diagram layouts, or tables for estimating the volume of lumber that can be sawed from logs of a specific length and diameter.

Log scale-The lumber contents of a log as determined by a log rule.

Log train– A log hauling truck designed to haul only short logs; logs usually less than 20 feet long. The normal log truck needs bunk and side logs of 32 or more feet long to bridge from the front to the rear bunks.

Logging truck- A special 18-wheeled truck designed to haul logs from the woods to the mill.

Logger– A worker employed in the woods producing wood products or in the support of such production, such as road construction.

Logging– Any or all part of converting trees into logs and transporting them to an unloading area.

Long butt– A swelled or cull portion cut off of a butt log.

Long corner– a) The distance from the landing to the farthest point of the setting. b) A small patch of timber in a setting that is difficult to yard or is unreachable.

Long log– To produce logs over 20 feet long , commonly 32 to 40 feet long. AKA “long wood”.

Lowboy or Lowbed– A heavy equipment moving truck capable of transporting logging and earthmoving equipment distances greater than which they would move themselves.

M

Machine rate– The cost per unit of time to own and operate a piece of equipment.

Mainline– The cable used to haul logs into the landing. Some cable yarder configurations, such as running skyline, may have more than one mainline.

Mainline block– The block on the spar or tower through which the mainline runs.

Man WagonA vehicle used for crew transportation to and from the woods. Also known as a Crummy.

Marginal log– The smallest log, in volume, that it pays a logger to remove from the woods. Often thought of as the breakeven log.

MBF– Thousand board feet. Often the log rule being used is appended, such as “MBF, Scribner.”

Mobile spar or tower– A collapsible metal tower used in cable logging.  AKA “Portable spar or tower”.

Mobile tailhold– A crawler tractor or hydraulic excavator fitted with a fair lead or short spar used to hang tailblocks which simplifies and speeds up road changes.

Multispan skyline-A skyline having one or more intermediate supports.

N

Non-clamping carriage– Skyline carriage which is held in place by counter-tension of the mainline(s) and the haulback line, rather other than clamping to the skyline line a clamped carriage, which clamps to the skyline when stopped and picking up logs.

Notch– A wedge-shaped piece cut out of a stump to prevent a guyline or block strap from slipping off.

Nubbin– A metal knob or collar attached to the end of a choker, allowing it to be secured to a choker hook.

O

Off-highway truck– A truck designed to handle loads exceeding legal highway size and weight restrictions.

Offside– The side opposite that on which the cutter must stand to fellor buck a tree.

Open-side carriage– A skyline carriage that opens on one side to enable it to pass intermediate support jacks.

Opening line– A line used to open a grapple.

Optimum road spacing– The distance between parallel timber access roads which minimizes total logging cost.

Ordinary lay– AKA “Regular Lay“. The most common type of wire rope used in logging. The wires making up the strands are laid in the opposite direction than the strands themselves.

Outhaul– The portion of a cable yarding cycle where the butt rigging or carriage returns to the timber from the landing for another turn.

Overrun– The lumber tally overage (MBF) produced from a MBF of log scale. e.g. If you get 1200 BF of lumber from 1000 BF of logs, then you have 20% overrun. Overrun is a product of the log scale being used (assumptions inherent in the log scale construction) and log diameter and length.

P

Paper plan– An initial timber harvest plan using available maps, aerial photos, and timber inventory data. It serves as the basis for field verification and adjustment to the final logging plan.

PC Logger– A Wintel desktop computer program which performs payload analysis for cable logging systems. Available from Oregon State University, College of Forestry.

Peaker– The top log on a loaded logging truck.

Pecker pole– A small log.

Peeler– A high grade log from which veneer is produced for plywood.

Peewee– A small merchanantable log.

Perpendicular felling– Timber felled at right angles to ground contour lines.

Pioneer To do initial work over rough or unclear areas or to make a pioneer road.

Pioneer road– A primitive tractor-trail type of access for moving equipment, workers, and material.

Portable spar– A collapsible metal tower used in cable logging. AKA “mobile spar or tower”.

Preload– To load logs or other wood products on to a trailer for subsequent transportation.

Prime mover– A tractor or other vehicle used to pull or power machines.

Profile– A graphic representation of the rise and fall of a section of ground surface as seen in a vertical section view. Most commonly used in road design and cable payload analysis.

Pulley– A wheel with a groved rim. AKA “sheave”.

Pulpwood– Small timber bucked to length (can be longwood or shortwood lengths) for use as a fiber source in a pulpmill.

Q

Quarter– To fell trees across the hill at an angle rather than straight up or down the hill.

R

Radio whistles– AKA “Talkie Tooter” or “bug”. A portable radio transmitter, carried by one of the choker setters or rigging slinger on a cable operation, which operates a whistle on the yarder and signals the yarder engineer what cable manuevers to inititiate. Talkie-tooter is a brand name for the most commonly used make of these radio controlled signalers and is often used generically, much like Kleenex or Coke, in woods conversations.

Radio controlled carriage– A carriage that is operated by remote control with radio signals from the ground.

Raising lines– The cables used to up-end a portable spar.

Reach– a) A metal member connecting a logging trailer to the truck tractor. b) The distance spanned by a skyline.

Reconnaisance– The initial field examination of a logging plan to determine its feasibility. AKA “recon”.

Recovery– That volume of timber which is recovered or saved after the felling and bucking operations are complete.

Reeve– To thread a line through a block or other opening.

Regenerative brake– A device used on an interlock yarder which induces a retarding force on an outgoing line drum and transfers a portion of the power absorbed to an incoming line drum.

Regular lay– The most common type of wire rope used in logging. The wires making up the strands are laid in the opposite direction than the strands themselves.

Reload– To transfer logs from one mode of transportation to another or between vehicles.

Relog– To salvage small timber, culls, or other residual wood products following the main logging operation.

Reprod– Short for reproduction or young trees.

Residual value– The actual or assumed value of a machine after it has been fully depreciated. AKA “salvage value”.

Rigging– The cables, blocks, and other equipment used in yarding and loading logs.

Rigging slinger– The headman on a rigging crew who is responsible for choker setters and chaser and who selects the logs to make up a turn.

Rig-up– To prepare a tailhold, spar, or tower for yarding by guying and anchoring it, attaching all rigging and stringing the lines.

Rig-up block– A small block through which the straw line is strung in the brush; usually wide throated so that splices and connectors for the straw line segments can pass through the block.

Rimpull– The torque that a machine can exert at the contact of its drive wheels to the ground; that is the tractive effort that a machine can exert to move itself.

Road– The path followed by a turn of logs yarded by a cable system. AKA “yarding road”,”skyline road”, or “skyline corridor”.

Road change– To move rigging and running lines to progressively yard logs from the next area in the felled and bucked timber. AKA “line change”.

Rolling resistance– The retarding force exerted by the ground against a vehicle’s wheels.

ROPS– Roll Over Protection Structure. A sturdy structure built into or fitted around the operator cab on certain equipment which protect operators if the machines overturn.

Rub tree– A tree used as a fender or pivot for a moving line to protect the remaining stand during yarding. Usually will be so badly damaged after use that it must be cut down

Running guy– See “sail guy”.

Running line– A moving cable.

Running skyline– A yarding system with three suspended moving lines, generally referred to as the main, haulback, and slack pulling, that when properly tensioned will provide lift and travel to the carriage.

S

Safe working load– The load a wire rope or structure may safely carry. Usually the ultimate or breaking load divided by the desired factor of safety.

Sag– The vertical distance between the chord and skyline, usually measured at midspan and expressed as a percentage of the span. Also known as “deflection“.

Sail guy– A guy line attached to end of the leaning tower on a swing yarder. The guy goes slack when the boom swings. AKA “running guy”. Largely made obsolete on modern swing yarders by the gantry tower which accomodates the guylines for the yarder.

Salvage value– See “residual value”.

Saw log– A log suitable in size and grade for producing sawn lumber.

Scale– To measure the volume of logs, expressed in MBF.

Scale deduction– The volume deducted for rot, breaks, or insufficent trim, from a log’s gross scale.

School marm– A forked top tree with two tops.

Self-loading logging truck– A logging truck with its own loading device, generally a knuckleboom mounted behind the cab. AKA “a self loader”.

Set– A cutting crew, generally composed of two people, a faller and a bucker. AKA “felling set”.

Setback– when a tree settles back on the backcut, opposite the direction in which it was supposed to fall.

Setting– The area yarded or skidded to one landing.

Shackle– A U-shaped metal connector with apin or threaded bolt through the ends. AKA “clevis”.

Shay swivle– A fitting used to attach the slack-pulling line to the mainline on a skyline system.

Shear– A mechanical cutting head, attached to a harvester, which severs the tree from the stump with a scissors-like action. Usually an undesirable cutting head for saw timber as it often splits the butt log and degrades the value of that log.

Sheave– A wheel with a groved rim. AKA “pulley”.

Singlejacking– When one person does the felling and bucking on a setting.

Shortwood– Pulpwood less than 10 feet long.

Shotgun– A two-drum, live skyline yarding system in which the carriage moves down the skyline by gravity, is lowered to attach logs, then raised and pulled to the landing by the main line. AKA “flyer”.

Show– Any unit of operation inthe woods, usually associated with logging, such as a highlead show.

Shovel logging– The use of a hydraulic loader to move and arrange logs into decks in the cutting area or to roads and landings. AKA Hoe Chucking, in Canada.

Side– A logging unit: the workers and equipment needed to yard and load any one unit of operation. e.g. “The company had a cable and skidder side operating in the woods.”

Sideblocking– A method of laterally displacing a slackline to facilitate log hookup or permit yarding a wider road. AKA “Dutchman block”

Sidehill yarding– Yarding logs parallel, or nearly so, to the ground contour lines.

Side slope-The average slope of the ground, in percent, along a yarding road on either side of a centerline.

Single-span skyline– A skyline without intermediate supports. Single span skylines are classified as short span if they reach out less than 2000 ft to the tailblock and long span if they exceed 2000 ft. Note, External yarding distances may be shorter than the spar to tailblock distance.

Siwash– A line not running in a straight line by being bent around a tree, stump, rock, etc.

Skid trail– See “cat road”

Skidder– A self-propelled vehicle used to transport logs, generally by dragging them with a grapple or chokers and can be wheeled or tracked.

Skidding– Dragging logs to a landing.

Skidding line– AKA Slack-pulling line.  A line on a slack-pulling carriage that is payed out to hook to chokers. Provides lateral yarding capability and obviates the need to lower the carriage to the ground each time to hook logs.

Skidroad– A path created by tractors for skidding logs, or any crude roadway or path cut by a bulldozer. AKA “cat road”.

Skyline– A cableway stretched tautly between two points and used as a track for a block or carriage.

Skyline carriage– A load-carrying device from which logs are suspended and which rides back and forth along the skyline on sheaves for yarding. Also called the “carriage“.

Skyline corridor– The location or pathway of a cable suspended between elevated supports so as to constitute a track along which log carriages can be pulled. Also called the “cableway“.

Skyline logging– A logging method in which a block or carriage rides on a skyline.

Skyline road– The path followed by a turn of logs yarded by a cable system. AKA “yarding road”,”road”, or “skyline corridor”.

Skyline profile– The ground profile under a skyline. A graphic representation of the rise and fall of a section of ground surface as seen in a vertical section view. Most commonly used in road design and cable payload analysis.

Skyline slope– The slant or inclination of the skyline chord, usually expressed in percent.

Slackline– A live skyline yarding system in which the carriage is pulled to the woods by a haulback line. The skyline is lowered by slackening the line to pemit the chokers to be attached to the carriage, and the turn is brought to the landing by the mainline. Lateral movement is provided by sideblocking. A slackline requires a three drum yarder.

Slack-pulling line– A line used to pull out the main or skidding line through a carriage. (see below).

Slack-pulling carriage– A carriage capable of pulling in logs (lateral yarding) through the use of a slack-pullingline.

Slash– Debris left on the ground after loggingis complete.

Snap guy– A guyline rigged on the same side of a standing tower yarder as the operating line(s) which prevents the tower from being pulled over backwards by the opposing guys if the operating line(s) break.

Snatch block– A block that can beopened on one side to allow a cable or rope to be laid in the block, instead of threading it through from one end.

Snag– A standing dead tree.

Snorkle– A wooded or steel boom extension mounted on a loader to increase the distance that logs can be reached for loading. A form of logging more common in western Canada than the U.S.

Snub– To lower anything. To assist one machine down a grade by holding it back with another and connected by a “snubbing line”.

Snubbing line– A line used in skyline logging to retard a load.

Span– The horizontal distance between two adjacent skyline supports.

Spar– A tree, wood mast, or metal tower used to support rigging for one of the many cable yarding systems. In the U.S. today, most commonly a mobile, portable tower is the rule. AKA a Tower.

Spot landing– A round or rectangular area cleared for use as a landing.

Spur road– A short, low standard branch road generally accessing one or two landings; often dead ending at the last landing.

Stage-felling– To fell timber in several successive cuts to reduce bole breakage and damage to understory reproduction. AKA “stage cutting”.

Stagged pants– Work pants shortened to prevent limbs catching the cuff and tripping the logger. Often left unhemmed and frayed at the bottom..

Standing skyline– A fixed skyline not running during logging operations; for example, a skyline anchored at one or both ends. The skyline length is fixed during yarding and is not raised or lowered during the cycles.Not used very often in today’s logging. Preference is given to live skylines or running skylines.

Station– A 100 ft long segment or distance of a road grade or skyline profile.

Strand– A component of wire rope consisting of wires spirally wound together which is then helically laid around the core to form the rope. See wire rope.

Strap– A short cable with an eye in each end. AKA “sling”.

Straw drum– A small drum on a yarder holding the straw line.

Straw line– A light cable, usually 3/8 inch or less in diameter, used to string heavier lines. Also called a “haywire”.

Strip– The area in which a set of cutters works- a cutting strip.

Stump pull– Splinters of wood pulled from the butt log. If the splinters are too long, stump pull is considered excessive and devalues the butt log.

Stumpage– The value of timber as it stands uncut. The residual value after all logging costs are taken from the delivered price of logs at the mill yard.

Swaged– To press on, such as a ferrule on a choker.

Swamp– To clear brush and obstructions for a cat clearing roads or skidtrails. The person doing this hand work is called a swamper.

Swing– a) To move logs to a landing from a distance deck to which they have previously been yarded.. AKA “shuttle logging”. b)The capability of a yarder to swing to either side to position logs beside the machine.

Swing yarder– Any yarder that swings on a turntable, as opposed to a standing spar yarder.

Swivel– a fastening device that allows the parts attached to it to rotate freely.

T

Tagline– a) A short line added to another line to lengthen it. b) A line used to position a loading grapple. c) The line from a carriage to which chokers are set AKA “drop line“.

Tailblock– A block at the back end of the yarding area which is used to guide the haulback line and is attached to an anchor or spar tree.

Tailhold– a) The anchorage at outer end of the skyline, away from the landing. b) A line securing a tailblock to a stump.

Tailspar– A spar at the outer end of a skyline system, away from the landing, which elevates and supports one end of the skyline. AKA “back spar”.

Tailtree– A standing tree used as tailspar.

Talkie-tooter– A portable radio transmitter, carried by one of the choker setters or rigging slinger on a cable operation, which operates a whistle on the yarder and signals the yarder engineer what cable manuevers to inititiate. Talkie-tooter is a brand name for the most commonly used make of these radio controlled signalers and is often used generically, much like Kleenex or Coke, in woods conversations. AKA a “bug”.

Tieback– A line attached to a secondary stump from the main anchor stump to distribute the load on the anchor. Commonly used where one large stump is not available to provide adequate anchorage.

Tightlining– a) In highlead logging, a method of lifting the logs or butt rigging over obstructions by tightening the haulback line with brakes while pulling themainline. b) Moving rigging from one road to another by changing the tailblocks and pulling the cable to the new road by tightening the mainline. [Note: Since highlead logging is usually a use don clear cut units, tightlining can not be done on units where residual trees are to be left standing in the unit.]

Tongs– A pair of curved arms with sharp points, pivoted like scissors to bite into a log for yarding or loading.

Top– To cut off the top of a tree down to a utilizable diameter for use as a spar. (Somewhat rare these days, as mobile, portable spars and towers are the rule.)

Total logging cost– the sum of road and yarding/skidding costs per MBF.

Tower– A steel mast or framework, generally protable, used instead of a spar tree for cable yarding.

a) Standing tower– A vertical, telescoping steel tower, usually cylindrical in cross-section, which is portable and transported fromlanding to landing for cable yarding.

b) Swing tower– A leaning tower, usually of lattice-box steel construction, mounted on a turntable and capable of landing logs to either side as well as in front of the yarder.

Tree jack– A J-shaped membe rused for skyline support at intermediate spars.

Trim allowance– The extra length allowed when bucking logs to account for end injury, uneven cut, and trimming of boards in the mill. Trim allowance may vary by local and scaling rule used, as well as by local tradition. In California, for example, this is commonly six inches of trim for a 16 foot or less log and 12 inches for a 32 foot log.

Turn– The logs brought to the landing in any one yarding or skidding cycle.

Twister– A line between anchors used for support by twisting the line with a sturdy stick to reduce its length.

U

Ultimate strength– See “breaking strength”.

Unclamped carriage– A carriage which holds position without the use of a skyline clamp.

Undercut– The wedge-shaped first cut made when felling a tree which determines the direction of fall.

Unhook– To remove chokers from logs at the landing.

Unit– See “cutting unit”.

Unloaded deflection– Deflection when no logs are being supported on the skyline. See “Catenary curve

Utility log– A log not meeting the grade requirements of a peeler or saw log, but which will produce at least 50% of its gross volume in pulp chips. AKA chip log.

V

Variable Cost– The total cost of operating a machine ($/unit) attributable to actual work, such as fuel, track wear, etc.

W

Wedging– The use of plastic wedges driven into the backcut (The final cut in felling a tree by hand, made on the side opposite the intended direction of fall, after the undercut) to direct the tree into its fall and to avoid setbacks (when a tree settles back on the backcut, opposite the direction in which it was supposed to fall) on to the chainsaw.

Whistle punk– A somewhat archaic term for the person who controls the whistle (see “Talkie Tooter“) on a cable yarding operation. Back in the old days, before radio signals, the whistle punk was a member of the yarding crew who was stationed where he could see the entire operation and could control the whistle signals through the use of a pull line back to the yarder.

Whole tree– Refers to felled trees, unbucked with limbs and tops intact.

Widow maker– A loose limb, top, piec eof bark or anything loose in a tree that may fall on a logger.

Winch– A powered drum used to reel in or pay out cable for yarding or hoisting.

Windfall– A tree or group of trees uprooted by the wind. AKA “windthrow”.

Windfirm– Tree(s) able to withstand strong winds.

Windrow– Slash, logs, or other material piled in a more or less continuous line to clear the intervening ground.

Windthrow– A tree or group of trees uprooted by the wind. AKA “windfall”.

Wire ropeA flexible steel rope made up of numerous wire strands twisted hellically together about a wire or fiber core.

Working strength– the maximum allowable load a wire rope or other material should be stressed to and still maintain the desired “factor of safety”. Usually this load is less than the elasticity limit of the wire rope or other material.

Wrapper– A wire rope placed across a load on a logging truck to secure the load. AKA “binder”.

Y

Yarder– A machine or system of winches used to haul logs into a landing. Often combined with a portable tower. Technically the yarder is just the power and winch system, but in practicallity today, it is the whole machine including the tower.

Yarder engineer– The person who operates and is responsible for the yarder.

Yarding– The act or process of conveying logs to a landing. In common practice, yarding is often reserved for cable logging, while skidding is used for ground based logging.

Yarding crane– Any yarder that swings on a turntable, as opposed to a standing spar yarder. AKA a “Swing yarder”

Yarding road– The path followed by a turn of logs yarded by a cable system. AKA “road”,”skyline road”, or “skyline corridor”.

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