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Glossary of Wood Terms

Wood Terms
Establishment of forest crops by artificial methods, such as planting or sowing on land where trees have never grown.
Age class
Any interval into which the age range of trees, forests, stands or forest types is divided for classification and use. Forest inventories commonly group trees into 20-year age class groups.
Lumber or other wood products that have been either dried by exposure to natural atmospheric conditions outdoors or in an unheated shed or dried to equilibrium with the surrounding atmosphere. Moisture content of air-dried wood fiber depends on relative humidity, temperature, and length of drying period. Also referred to as air seasoned and contrasts with kiln-dried (KD) lumber.
Allowable cut
The amount of wood that can be removed from a landowner's property during a certain time span, without exceeding the net growth during that same time on the property.
Final cut in felling a tree. Made on the opposite side of the direction of fall
A delivery by tractor-trailer originates from where the trailer is loaded, the load is delivered to a destination, then the trucker returns home. If the return is also a paying load to be delivered to the vicinity of the trucker's home, that load is called a backhaul. If the trucker returns home empty, that run is called a "deadhead."
Band sawmill
An evolution in sawmill technology that uses a thinner band saw blade (less kerf therefore less sawdust waste) than a circular saw. A bandsaw also has teeth on both sides that allows cuts to be made in two directions instead of just one, improving efficiency and productivity.
The outer protective layer of the tree. Severely damaged bark on a tree is a defect that can lower the value of the its logs. At the sawmill, logs are first debarked, then slabs are cut off leaving a rectangular or square cant to be cut into lumber. There are two main types of debarkers: Rosserhead and Ring debarkers. Before raw bark is sold as bark mulch, it is ground in a tub grinder (hammermill) to give it the proper texture and consistency. Bark quality is a function of color.
Basal area
Cross sectional area of a tree, in square feet, measured at breast height. Used as a method of measuring the volume of timber in a given stand.
Basic silviculture
1) An administrative term describing the the practices necessary to establish regeneration of the desired species at specified densities and stocking, free from competing vegetation, and within a certain time limit. 2) Silvicultural activities required by law. See also intensive silviculture.
Any framing member placed to support a load. Also called a girder.
Best Management Practices (BMP)
A series of forest practices thought to be the best possible for a specific region and forest type. BMP are highly promoted by the American Forest and Paper Association's Sustainable Forestry Initiative (SFI).
Big box
Large, warehouse-type lumber and building material stores catering to do-it-yourself (DIY) shoppers. Home Depot and Lowes are examples.
Total woody material in a forest. Refers to both merchantable material and material left following a conventional logging operation. In the broad sense, all of the organic material on a given area; in the narrow sense, burnable vegetation to be used for fuel in a combustion system.
Biomass boiler
Biomass boilers burn bark, sander dust and other wood-related scrap not usable in product production. Also called "hogged fuel" boilers, biomass boilers make steam and heat for mill use.
Blow down
Tree or trees felled by wind. Also known as windfall.
Blue stain
A fungus discoloration, mostly bluish, but somtimes grayish, blackish, or brownish in appearance; found mostly in sapwood, common in pines and in the warmer months of summer. At one time this was thought to be a serious defect; now it is used as high-quality interior finish.
Board foot
A volume of lumber that measures 1" x 12" x 12". The number of board feet in a log is estimated using one of three log scales: Scribner, Doyle, or International Rule. The standard used in Massachusetts is the International Rule. The actual yield of a log after sawn into lumber is often greater than the estimated yield. Both logs and lumber are sold by the thousand board feet or MBF.
Bole wood OR Pruned Butt
The lower section of the trunk of a tree from the ground to the first limb or branch in natural forest. . Tree stem that has roughly grown to a substantial thickness, capable of yielding clear sawn timber, veneer logs, or large poles . In plantation pine clearwood silviculture , the bottom section (often to 6.0m height)where branches are pruned to allow for rapid growth of sapwood without branch defects to maximise clearwood recovery in sawn timber and veneer.
Short logs to be sawn for lumber or used for veneer. Also: -Any short log, as a pulpwood bolt or pulpwood stick. -Any short stick, generally between 2 and 8 feet long. -Also referred to as a block.
Bone-dry ton (BDT)
Wood pulp or residue that weigh 2,000 pounds at zero percent moisture content. Also known as an ovendry ton.
A lumber defect referring to deviation from a straight line drawn end to end along the wide face of a piece of lumber (see also crook).
British thermal unit (BTU)
Measure of the amount of heat required to raise 1 pound of water 1 degree Fahrenheit. Amount of latent heat available to be released when a substance undergoes combustion.
Cutting a felled tree into shorter specified log lengths; rough cutting logs for length.
To gather trees or logs into small piles for subsequent skidding by other equipment. To assemble logs together to form a load for transport.
Base of a tree. Large end of a log.
Butt cut
The first cut above the stump of a tree.
Butt log
First log cut above the stump. Also known as butt cut. (See also: Pruned Butt).
Butt rot
Decay or rot characteristically confined to the base or lower bole of a tree.
To make the surface of paper smooth by pressing it between steel rollers during manufacture.
The layer of cells between the woody part of the tree (heartwood) and the bark. Division of cambium cells results in diamteter growth of the tree through formation of wood cells (xylem) and inner bark (phloem).
The forest layer made up of the crowns of the tallest trees.
1) Log that is squared on two or more sides and to be sawn further. 2) A log is first debarked then the rounded slab or outside portion of the log is cut off by the sawyer. The remaining square or rectangular portion of the log is called a cant. Lumber is cut from the cant. The more pieces of lumber cut, the more sawdust (waste byproduct ) is produced, reducing the log yield of marktable board feet.
A thin, stiff paperboard made of pressed paper pulp or sheets of paper pasted together. Used for playing cards, greeting cards, etc. Corrugated containers are not made of cardboard.
The sawmill device on which a debarked logged is placed which moves the log back and forth through the saw blade creating slabs, cants and lumber. The log is also turned on the carriage before making the next cut.
A lumber defect referring to the separation of wood fiber across the annual growth rings. Splitting of the wood in logs or lumber, often the result of drying.
A paperboard, thicker than cardboard, used for backing sheets on padded writing paper, partitions within boxes, shoeboxes, etc.
Short length of flexible wire, rope, or chain used to attach logs to a winch line or directly to a tractor. -Noose of wire rope for hauling a log. -Short length of wire rope that forms a noose around the end of a log to be skidded and is attached to the skidding vehicle or to the butt rigging in a wire rope logging system.
Chromated Copper Arsenate (CCA)
The most commonly used chemical for pressure treating lumber.
Circular sawmill
The traditional sawmill uses a circular saw (large version of hand held power saw). Circular saws are thicker (larger kerf) than band saws and produce more sawdust. Logs can be cut moving on the carriage in only one direction, then the carriage returns and turns the the log for the next cut.
1) Lumber or logs that are free or practically free of defects. First quality lumber or log.2) A select grade of lumber.
To harvest all trees from an area of forest land in a single cut.
Closed canopy
The description given to a stand when the crowns of the main level of trees forming the canopy are touching and intermingled, and form a barrier to light penetrating the forest floor from above.
Co-Gen Operation
Refers to the production of usable steam and electricity using a particular kind of fuel (for example, woodchips, oil, coal, hydro).
Codominant trees
In stands with a closed canopy, those trees whose crowns form the general level of the canopy and receive full light form above, but comparatively little from the sides. In young stands, those trees with above average height growth.
Commercial thinning
A silviculture treatment that "thins" out an overstocked stand by removing trees that are large enough to be sold as products such as poles or fence posts. It is carried out to improve the health and growth rate of the remaining crop trees. As compared to "juvenile spacing."
Composite lumber
See "engineered wood products".
Comprssion wood
When an actively growing softwood stem is tipped from the vertical, it almost immediately begins producing wood on the underside of the leaning stem that is different from normal. Stems tipped as little as several degrees from the vertical may begin producing abnormal cells within several hours of the change in stem orientation. This wood, known as compression wood, is of interest because its properties are considerably different from, and much less desirable than, normal mature wood. In fact, compression wood has many of the same properties as juvenile wood.
Concentration yard
A large lumber storage and reload facility.
Tree that is a gymnosperm, usually evergreen, with cones and needle-shaped or scalelike leaves, producing wood known commercially as softwood.
Construction and demolition (C&D)
Though lumped together to refer to wood waste produced by construction or by demolition, the products can be quite different. Construction wood waste can be clean dimensionally cut lumber such as board ends or cutoffs. Demolition wood waste is often contaminated with nails, sheetrock, paint, etc. Markets for C&D are limited by how "clean" and free of contaminants the wood is. Some businesses specialize in processing and disposing of C&D.
Forst regeneration by sprouting (vegetative reproduction) from stumps or roots.
Stacks of hardwood 4' high by 4' wide by 8' long. It is the measure by which firewood is customarily sold , sawdust is sometimes sold, and small diameter logs sometimes bought. One cord is the equivalent of 128 cubic feet, 4.7 cubic yards. The weight of a cord varies if it is green (freshly cut), seasoned (partially air dried), or dry (KD or kiln-dried).
To build a road by cross-laying it with saplings or small poles.
Corrugated containers
Containers made with corrugating medium and linerboard.
Corrugating medium
The wavy center of the wall of a corrugated box which cushions the product from shock during shipment (see flute). This layer can contain up to 100% post-consumer recycled fiber content without reducing its ability to protect the product.
1) A lumber defect referring to a deviation from a straight line drawn end to end along the narrow face of a piece of lumber. 2) Abrupt bend in a tree or log.
To cut a piece of lumber perpendicular to its length.
The live branches and foliage of a tree.
A pulpwood measurement, equaling 100 cubic feet of solid wood.
A lumber defect referring to a deviation from a straight line drawn edge to edge across the face of a piece of lumber.
Cut to length (CTL)
New timber harvesting equipment allows loggers to fell trees, delimb them, and cut them to market length specifications before loading them on forwarders bound for the landing. CTL equipment is a recent trend in logging operations. Also applies to sawn boards produced for specific purpose eg pallet boards.
DBH (Diameter breast height)
The diameter of a tree at breast height (4.5 feet above ground) together with the estimated height of the usable logs in a tree is used to determine the volume of lumber likely to be yielded in a log depending on the log scale used (Scribner, Doyle or International Rule).
Term applied to trees (commonly broadleaf) that usually shed their leaves annually. Also known commercially as 'hardwoods'.
Dominant trees
Trees with crowns extending above the general level of the canopy and receiving full light from above and partly from the side; taller than the average trees in the stand with crowns well developed. Also see codominant trees.
Doyle Log Rule
In use since about 1870, this scaling method deducts a full four inches for slabs. It grossly underestimates the yield on small diameter logs (less than 14") . Every fourth Doyle load could be considered free in comparison to International rule, if the logs are within 14 to 20" inches in diameter and the prices per MBF for both scales were identical. The variance between Doyle rule and other rules is based on diameters, rather than lengths. (Also see Scribner and International Rule.)
Dressed lumber
Lumber that has been trimmed and planed at the sawmill. When done for sizing purposes only (not moulding quality finish) sometime referred to as "gauged" or "planer gauged"
Dry lumber
As applied to softwoods, lumber sold as "dry" or "kiln dried" is at 19% or lower moisture content, as specified by the relevant Standards. Hardwoods are generally considered dry when at 10% or lower moisture content, although there is no definitive standard as with softwood species.
Dry weight
The oven-dry weight, or simply dry weight, is the weight of wood after drying to a constant weight at a temperature slightly above the boiling point of water (215° to 220°F).
The science that studies the interrelationships, distribution, abundance, and contexts of all organsims and their interconnections with their living (biotic) and nonliving (abiotic) environment, in addition to the processes that determine ecosystem function, change over time, and response to disturbances. Ecology takes two main forms: (1) systems ecology, which relies heavily on computer modelling and inventory data; and (2) field ecology, which studies organisms and communities in their natural settings.
Lumber cut on circular or band headrigs from the outside portions of logs does not have square edges. These pieces must be passed through a machine called an edger that can make two or more lineal cuts simultaneously. The edgings are chipped for use in generating power or for use in paper production. Square-edged lumber must be trimmed to length.
Engineered Wood Products
A composite wood product using glued fiber, lumber and/or veneer to meet specific design criteria. Such products include laminated veneer lumber (LVL), parallel strand lumber (PSL), and structural I-beams. Products under development include various molded, extruded, and other structural and non-structural composites. Although engineerred wood products have a number of advantages over solid lumber (including the ability to make large-sized members from small diameter trees), engineered wood products are more costly to produce than lumber and require the use of more energy to manufacture. Englemann Spruce Large Pole pine
A harvesting machine that cuts a tree by shears or a saw and then piles it.
Flatbed trailer
Used to haul lumber. Flatbed operators may haul logs if they carry portable stakes. The number of stakes, stake height and distance between stakes determines the number of log tiers and length of logs in each tier a flatbed may carry. Flatbed operators will carry sawlogs before they will carry pulp logs, because the higher value of sawlogs ensures they are more likely to receive an acceptable rate. Lower value pulp logs may require quibbling over nickels and dimes in the rate.
A log sawn on two or more sides, In NZ generally refers to size of 200mm wide or more x 100m thickness or more , Sizes under this crossection often called mini flitch
Forest management
The practice of applying scientific, economic, philosophical, and social principles to the administration, utilization and conservation of all aspects of forested landscapes to meet specified goals and objectives, while maintaining the productivity of the forest. Forest management includes the subset of all activities known as timber management, but also involves planning and managing forested landscapes for fish and wildlife, biological diversity, conservation measures, parks, wilderness recreation, and aesthetic values. Forest management is an all encompassing activity and is not to be confused with the more restrictive activities associated with timber management.
Forest Products Society (FPS)
An international organization comprising forest products firms, trade associations, researchers, academics, landowners, government, consultants, and other stakeholders with approximately 2,700 members in North and South American, Asia, and Europe. The FPS publishes the Forest Products Journal 10 times a year. URL:
A profession embracing the science, business, and art of creating, maintaining, and managing forested landscapes and their many component parts to produce consumptive and/or nonconsumptive outputs for use by humans or other species in a manner that does not cause ecosystem degradation.
Glue laminated beams
Beams made of lumber glued together. Replacements for solid wood timbers and steel beams.
Forestry Certification
Landowners who actively manage their woods can apply for certification of sustainable yield forestry. Two agencies perform reviews and issue certification for the Forest Stewardship Council (FSC): the non-profit Smartwood and the for-profit SCS (Scientific Certification Systems). Both agencies charge to ensure that land is properly and sustainably managed and that loggers employ best management practices (BMP) to cut wood on certified woodlots. To maintain its certification status from landowner to consumer, sawmills must also be certified in chain of custody arrangements, that is, they ensure that certified logs are stored and milled separately from non-certified logs. It was originally thought that certified logs would sell at a premium but that has not been the case in New Zealand. IT SHOULD BE NOTED THAT ALL NEW ZEALAND PINE IS FROM MANMADE FORESTS AND AS SUCH IS SUSTAINABLY MANAGED BY DEFAULT AS CAN BE DEMONSTRATED BY NATIONAL HARVEST STATISTICS
Green weight
The term green weight specifically refers to the weight of freshly harvested wood that has the same moisture content (MC) as the standing tree. MC is defined as the weight of water in the wood expressed as a percentage of the weight of the oven-dry wood (wood from which all moisture has beensd removed). Also see "dry weight."
Ground wood chips
Ground wood is usually produced from a hammer mill or tub grinder and appears shredded and fibrous with irregular sizes, depending on the screen or grate used. Ground wood is easily disinguished by its geometry from wood chips produced from mill chipper or a whole tree chipper (WTC). WTC and mill chips appear square and evenly cut rather than fibrous and irregular.
Ground wood paper
Newsprint and other inexpensive paper made from pulp created when wood chips are ground mechanically rather than refined chemically.
Hardwood comes from deciduous trees that lose their leaves during the winter. Hardwoods have traditionally been used in making such products as furniture, strip flooring, interior trim, cutting boards, novelties, and so forth. Wood used in making these products is typically in the form of relatively small and defect-free pieces which are subsequently glued together; it is also generally more costly than wood from softwood species. Because of these factors, hardwood lumber is manufactured to non-standardized length and width dimensions which will minimize trim waste. For the same reasons, such lumber is measured relatively accurately, with rounding of measurements in small increments.
In a cross section of a log, the heartwood is the center and dead portion where growth rings appear. Also see bark and sapwood.
A metric unit of area, 100 metres by 100 metres (10,000 square metres) or 2.471 acres.
The practice of harvesting only the higher value trees and leaving the lower value trees in the woods ("Take the best and leave the rest"). It is frowned upon in this era of sustainability, and much effort is being made to find suitable markets for lower grade logs.
Improvement cutting
The removal of trees of undesirable species, form or condition from the main canopy of the stand, to improve health, composition and value of the stand.
Intensive silviculture
Refers to the treatments carried out to maintain or increase the yield and value of forest stands. Includes treatments such as site rehabilitation, conifer release, spacing, pruning, and fertilization. Also, known as incremental silviculture. Compare with basic silviculture.
International Log Rule
In use since about 1906. Generally regarded as the most accurate of the three scaling methods, International log rule deducts only 2.12 inches for slabs and 1/4 inch for kerf. (Also see Scribner and Doyle Rules.) It is the standard rule used in Massachusetts.
Juvenile spacing
A silvicultural treatment to reduce the number of trees in young stands, often carried out before the stems removed are large enough to be used or sold as a forest product. Prevents stagnation and improves growing conditions for the remaining crop trees so that at final harvest the end-product quality and value is increased. See also commercial thinning.
Juvenile wood
The term juvenile wood refers to wood formed early in the life of a tree. By most measures, juvenile wood is lower in quality than wood which forms later; this is particularily true of the softwoods. Juvenile wood is of greatest concern in lumber and other products in which wood is used in solid form. Juvenile wood is of lesser concern in paper and fiber products and in products in which wood is reduced to individual fibers, fiber bundles, or small pieces prior to product manufacture. The two most troubling characteristics of juvenile wood are that: -It shrinks and swells along the grain as moisture content changes. -Strength is lower, and in some cases much lower, than mature wood of the same tree
The width of the sawblade (circular or band) and the source of sawdust. The more traditional circular sawblades are wider (1/4" to 3/8") than the newer band saw blades (1/8" to 3/16") and produce more sawdust, a waste byproduct of sawmills.
Freshly cut green lumber may be sold green or first dried in a kiln to accelerate removal of the moisture in the wood. Drying wood in a kiln is an art to ensure that the wood dries evenly to retain its strength and aesthetic properties. Different species dry at different rates. Kiln dried lumber commands a higher price than green or air dried lumber.
Areas of the main stem of a tree in which the base of a branch has been overgrown through diameter growth of the main stem are called knots. Knots in lumber or veneer are cross sections of tree branches
Kraft paper
Heavy brown paper sometimes treated to be water repellant.
Laminated Veneer Lumber (LVL)
Structural grade timber veneers glued together under pressure to form a dimensionally stable and uniform product. An engineered (man-made) wood product that is a substitute for dimensional lumber. LVL is glued such that the grain direction of all veneers is parallel; this is different than plywood in which the grain directions of adjacent veneers is perpendicular to one another. LVL and other composite lumber products have a number of advantages over solid lumber, including the ability to make large-sized members from small diameter trees. Such products also allow the dispersion of gross defects such as large knots.
That part of a wood lot to which fresh cut logs are skidded or forwarded, accumulated, cut to length (if not cut to length in the woods) , stacked, and loaded onto trailers for delivery or chipped and blown into trailers.
The inner and outer layers of paper that form the wall of a corrugated container.
Measurement term for log and lumber volume: 40 cubic feet of logs equals 1.13 cubic meters, and 50 cubic feet of lumber equals 1.416 cubic meters.
Log defects
Defects affect the log scale and value for which the log may be sold or bought. Deductions for defects are subjective depending on the scaler and a source of confusion in the buy-sell transaction. Defects may include red knots, black knots, rot, burned area of a log, crook, sweep, or doglegs.
Log scales
Determines the value of a log by estimating number of board feet of lumber it will yield (less allowances for bark, slab and kerf). Helps log sellers understand what they are getting for the product of their labor. Log buyers can usually predict the actual yield of board feet from a log depending on the log rule used. Three major log scales are used: Scribner Log Rule, Doyle Log Rule and International Log Rule, although there are others (Maine and Roy). It is vital that sellers understand the differences between the scaling methods so as not to be taken advantage of. Savvy buyers are flexible in the rules they use. A common rule of thumb is that International is always 25% better than Doyle, and Scribner is always 15% better. Doyle and International are dramatically different for small diameter logs, yet very similar for large diameter logs. If the average diameter range of logs is 14" to 20", you can convert Doyle to International by multiplying 1.2 and Scribner to International by multiplying 1.11. For example, if logs for a particular site scaled about 5,000 board feet in Doyle, this would convert to 6,000 board feet in International and 5,500 board feet in Scribner.
Log trailer
Built with permanent stakes to carry sawlogs or pulp logs. Log trailers may have a grapple loader mounted front or rear in which case the operator can load himself. The increased cost of a loader on a log trailer means the trucker's rate will likely be much more. Without a loader, the logger must use his equipment to load the log trailer.
Lumber is simply solid wood that has been sawn to a particular size. Traditionally produced from very large diameter logs, lumber is now often made from logs as small as 8 to 12 inches (20 to 30 cm) in diameter. A variety of equipment is used to produce lumber. Newer mills that process softwood logs combine scanners, computers to calculate optimium sawing sequences, and high speed, thin-kerf saws designed to obtain maximum lumber yield. The newest "lumber" products are not lumber at all in the traditional sense, but composite products created from veneers, thin flakes, or other materials such as plastic. Such products have more uniform strength properties than solid-sawn wood and can be made to large sizes even when using small trees as raw material. Lumber is always measured, bought, and sold based on nominal, rather than actual, sizes. Measurements are affected by moisture content and, in the case of hardwoods, by whether boards are surfaced or unsurfaced. Also see Yield.
Market pulp
White pulp from hardwood trees that is dried into thick blotter-like sheets and baled for shipment to a paper mill for repulping to make paper products.
See thousand board feet.
Medium Density Fiberboard (MDF)
A panel product manufactured from wood fibers combined with a synthetic resin or other suitable binder. The panels are manufactured by the application of heat and pressure by a process in which the inter-fiber bond is created primarily by the added binder. The typical density range for MDF is 31-50 lbs/cubic ft.
Merchantable timber
A tree or stand that has attained sufficient size, quality and/or volume to make it suitable for harvesting.
Mill chips
After debarking and before a sawmill cuts lumber, it saws off the outer four slabs to reduce the log to a square or rectangular cant. The slabs are mostly the sapwood portion of the log and may be resawn to save low quality boards (e.g., pallet boards), or the slabs are sent to the chipper. Most chippers pass their chips over a two-deck vibrating screen to separate the "overs," "accepts" and "fines." The "overs" are re-circulated through the chipper again and the "fines and sawdust" are blown into their own pile. The chip "accepts" are blown into a chip van trailer, blown into a pile on the ground to be loaded over the top of an open top trailer with a front-end bucket loader, or they are conveyed into an overhead bin which drops chips into an open top trailer.
Building materials made of finished wood that have been specially manufactured by a plant or mill. Millwork includes molding and trim, doors and windows and their frames, staircases, cabinets, and other specialty items.
A million board feet.
Moisture Content
Weight of the water within a piece of lumber measured as a percentage of the weight of the dry wood. Typical moisture content for kiln dried construction lumber is 15%. Wood absorbs or gives off moisture depending on the ambient moisture in the air. The percentage of wood that is not moisture is referred to as "dry solids," that is, dried construction lumber would be 85% dry solids. Product standards for lumber manufactured in the United States are developed under the jurisdiction of the U.S. Department of Commerce and administered by the American Lumber Standards Committee (ALSC). Members of the ALSC are representatives of various softwood lumber trade associations. As specified in the ALSC American Softwood Lumber Standard, softwood lumber is sold as "dry" if at a moisture content of 19% or less. Most hardwoods manufactured in the United States are produced to standards developed by the National Hardwood Lumber Association (NHLA). No single moisture content, however, is specified for hardwoods because the uses are more specialized. The moisture content must be specified by the buyer and agreed to by the seller; a 10% moisture content specification is common.
A trim piece of millwork used either strictly for decoration or for both decoration and to finsih a joint.
Mud Season
The period of weeks between winter and spring or summer and fall when the ground in a forest is largely mud, thawing or freezing between warmer days and colder nights. During mud season, heavy logging equipment is not permitted in the woods nor are trees cut during this time. Industry professionals that depend on a continuous supply of logs must account for these seasons and stockpile sufficient quantities to process during mud season. Truckers are usually available during mud season to haul logs from distant concentration yards which may have accumulated logs for mud season.
Raw bark peeled from a tree and ground in a hammer mill (tub grinder) and sold as a landscape ground cover. Mulch functions to reduce weeds, retain moisture by reducing evaporation, and insulates the ground in cold weather, in addition to providing an aesthetic appearance for one's garden.
Old growth
A forest of mature or over mature timber that is beyond its peak growing period.
Oriented strand board (OSB)
Structural panels made of narrow strands of fiber that are oriented lengthwise and crosswise in layers and bound together with resin. Depending on the resin used, OSB can be suitable or interior or exterior applications. Plywood and OSB are also referred to as structural panels and used in applications where strength and stiffness are required, e.g., roofs, walls, floors, etc.
That portion of the trees, in a forest of more than one storey, forming the upper or uppermost canopy layer.
Paper wrap (PW)
Heavy paper, wrapped around the top and four sides of a unit of lumbr, to protect it during transit and outside storage. Often a condition of sale.
Petrograd Standard
Measurement unit for softwood lumber volume equal to 165 cubic feet, 1,980 board feet, or 4,672 cubic meters.
Phytosanitary Certificate
A certificate issued by the MAF to satisfy import regulations of foreign countries indicating that the shipment has been inspected and is free from harmful pests and plant diseases.
A piece of sawmill equipment that planes rough lumber, leaving it smooth and uniform in size.
Planer mill
Although sometimes a separate facility, the planer mill is usually that part of a sawmill where lumber is planed, graded, and sorted.
Sheets of wood consisting of three or more sheets of wood glued and bonded by heat and pressure with the grain of each sheet running perpendicular to adjacent layers.
Precision end trimmed (PET)
Lumber trimmed smooth on both ends and varying no more than 1/16" in nor more than 20% of the pieces. May be a condition of sale.
Primary Wood Products
Include logs, softwood lumber, hardwood lumber, plywood, oriented strand board (OSB), medium-density fiberboard (MDF) and particle board.
Procurement forester
A forester employed by and accountable to a sawmill or paper mill and who is responsible for providing a continuous supply of logs for his/her employer. Also referred to as industrial foresters, they purchase trees on the stump or at the landing from landowners or loggers.
Pruning of lower dead branches leads to an almost immediate improvement in the quality of wood produced. After several years new wood will cover the severed branch stubs and the subsequently produced wood will be knot-free. This treatment has no effect upon tree growth. Pruning can significantly improve the quality of saw and veneer logs. For maximum effectiveness pruning should be concentrated on lower portions of larger trees which will not be harvested for some 30 to 40 years following treatment. Heavy pruning which removes a substantial portion (i.e., more than one-third) of the green crown should be avoided.
Pulp logs
Logs of lesser value (smaller in diameter with acceptable defects) than sawlogs, of greater value than cordwood. Pulp logs are usually bought by the ton to be debarked, reduced to chips, and used to manufacture pulp and paper.
Reaction wood
Reaction wood is wood formed in trees where the main stem is tipped from the vertical. It also often forms following the deflection of a lateral stem (branch) from its normal orientation. Reaction wood formed in hardwoods differs from that formed in softwoods. In softwoods, reaction wood is called compression wood; reaction wood in hardwoods is called tension wood. Both compression wood and tension wood are lower in quality than normal mature wood. As with juvenile wood, reaction wood is viewed as least desirable in lumber and in other products in which wood is used in solid form.
The natural or artificial restocking of an area with forest trees.
The process of sawing lumber in two lengthwise, parallel to the wide face. It is usually, though not always, done through the middle of the board, producing two equal sized boards, each approximately half the thickness of the original. Resawing changes the thickness of the lumber but not its width. Also see Ripping.
Related to or living or or located on the bank of natural watercourse, such as a stream or river or lake or tidewater.
The process of sawing lumber in two lengthwise perpendicular to the wide face. Ripping changes the width of the lumber but not its thickness. Also see Resawing.
Rotation age
The period of years required to establish and grow a timbercrop to a specified condition of maturity. The intended age of harvest of mature trees. Long rotations mostly affect those features that are desirable in lumber and in structural and non-structural products made largely of wood in solid form. Harvest age has less impact on the usefulness of wood for use in paper and fiber products and in products in which wood is reduced to small pieces prior to manufacture.
To harvest trees that are dead or in poor condition but can still yield a forest product.
Sanitation cutting
The removal of damaged or diseased stems to prevent the spread of insects or disease.
A young tree of small diameter, typically 2 to 5 inches at DBH.
The layer of new wood surrounding the denser, dead heartwood of a tree and under the cambium and bark layers.
Scaling (lumber or logs)
Logs are measured (or scaled) for the purpose of estimating the amount of lumber that can be obtained. Once logs have been processed into lumber it is again necessary to quantify volumes produced. The process of measuring lumber is called lumber scaling. The volume lumber yielded from a log may be greater than the estimated volume of lumber. Also see Yield.
Scientific Certification Systems (SCS)
One of two independent organizations inthe U.S. appointed by the Forest Stewardship Council to certify landowners engaged in active forest management. SCS is based in Oakland, CA and is a for profit operation. The other agency is Smartwood based in Manchester, VT.
Scrag mill
A special high-speed sawmill designed to saw small diameter logs. A skrag mill typically has two circle saws arranged in parallel which remove two slabs with one pass of the log producing a two-sided cant. Not all sawmills have a scrag capability and so are limited to purchasing only larger diameter sawlogs.
Scribner Log Rule
In use since before 1846. This scaling rule is based on a diagram of the size and number of 1" boards that could be sawn from it allowing for 1/4" kerf.
Shade tolerance
The capacity of a tree or plant species to develop and grow in the shade of and in competition with other trees or plants.
A separation of the wood along an annual ring (ring shake)or cracks radiating from the heart (heart shake) caused by frost, wind, or felling of the tree.
A wind barrier of living trees and/or shrubs maintained to protect farm fields or homesteads.
Shelterwood cutting
Any harvest cutting of a more or less regular and mature crop, designed to establish a new crop under protection of the old.
The art and science of growing and tending a forest. It includes assessing sites before they are harvested to determine what is growing there now, evaluating soil conditions to determine moisture and nutrient levels as well as assessing the types of plants that are growing on the site.
A wheeled or tracked vehicle used for sliding/dragging logs from the stump to the landing.
The exterior portion of a log removed in sawing timber.
Tree tops, branches, bark, and other debris left after a forest operation.
Evergreen trees, conifers, cone-bearing trees or wood cut from these trees. Softwood lumber has long been the mainstay of the residential construction industry where it is used in relatively large-sized pieces. Though some of this wood, such as that used for siding, must be of good appearance, most requires only adequate strength. Because of these factors, and because construction requires material of uniform size which can be stockpiled economically (meaning a relatively small number of standard sizes), softwood lumber is manufactured to standard sizes and is measured accordingly.
A pole, tower or tree used in cable logging to raise the mainline off the ground.
Spike top
A tree with a dead top, usually a mark of declining vigor.
The less dense, larger wood cells of an annual growth ring. Also called earlywood to refer to the fact that it is the wood formed early in the growing season. See also summerwood.
A community of trees sufficiently uniform in species, age, arrangement or condition to be distinguishable as a group from the forest or other growth on the area.
Stem Wood
See Bole Wood.
When kiln or air-dryin wood, stickers are pieces of wood placed perpendicularly between layers of boards to allow for airflow through the stack. Stickers are usually placed 12 to 18 inches apart and directly over any support beams under the stack. Placing stickers as close as possible to the end of the boards helps to llimit end checking and reduce warp.
Structural I-Beams
Structural I-Beams were developed to take advantage of the fact that compression and tension stresses are greatest at the top and bottom edges of a beam as it is subjected to a load. By concentrating the amount of wood at the the top and bottom edges and by paying close attention to the quality of wood used at these locations, beams are made that have high strength but which use far less wood than solid lumber. Such products are widely used today and were used in 19% of the homes built in the United States during 1996. Structural I-beams are used for the most part as floor joists, replacing 2 × 12, 2 × 10, and 2 × 8 solid-sawn lumber that has traditionally been used for joists.
The value of timber as it stands uncut in the woods. The price charged for the right to harvest timber from publically or privately-owned forest land. The University of Massachusetts publishes a local stumpage fee report quarterly based on responses to a survey of local landowners and loggers.
The denser, later-formed wood of an annual growth ring. Also known as "latewood" relating to the time in the growing season that these cells are produced.
Death of cambial tissue on one side of a tree, caused by exposure to direct sunlight.
Lumber that has gone through a planer so that its sides are smooth and uniform in size.
Sustainable Forestry Initiative (SFI)
The program and polices formed by the American Forest and Paper Association (AFandPA). SFI was developed in response to criticism from environmentalists aimed at logging practices that did not promote forest sustainability. SFI is the industrial counterpart to programs promoted by Smartwood (non-profit)and Scientific Certification Systems (for profit) which promote and certify landowners engaged in proactive and sustainable forest management. AFandPA requires all its members to comply with SFI principles among which is the requirement that forest management be "certified" by an independent third party. SFI certification can be easily confused with "green certification" promoted by the Forest Stewardship Council (FSC).
Sustained harvest
A level of harvest that does not exceed annual growth, so that at least as much is available for harvest in 50 years as today.
A gradual (but pronounced) bend in a log, pole, or piling; considered a defect. Sweep in a log is analogous to "bow" in a piece of lumber.
Describes a tree greatly enlarged at the base.
The thickness, width, and length piece count of lumber shipped on a particular order.
Tare Weight
Tare weight is the weight of tractor-trailer with no load. A tractor trailer typically weigh 30,000 to 35,000 pounds leaving a legal load weight of 45,000 to 50,000 (22 to 25 ton). The heavier overweight loads not only pay the trucker more, but are also more wear and tear on trucking equipment.
The process of removing excess and poorer quality trees from a stand to allow the remaining trees adequate sunlight, nutrients and moisture and to grow at an even rate which improves stand value. Trees that remain when surrounding trees are removed in thinnings or partial cuttings respond to this more open environment by stimulated crown development and the formation of wider growth rings along the bole. Effects upon growth are often dramatic. The effect on density of wood formed thereafter is largely unpredictable. However, the timing of thinnings has much to do with the effect upon wood quality and thus should be considered when developing a management plan.
Thousand Board Feet (MBF)
One board foot is wood that measures 1" x 12" x 12". Logs and lumber are measured by MBF or thousand board feet. MBF is determined by one of three major scaling rules: Scribner, Doyle, or International Rule. The board feet scaled for logs is an estimate only. The actual board feet yield depends on how the sawmill cuts the log. It is possible for a log to produce more board feet than was estimated producing an overrun.
Lumber 5" or more in thickness.
Square-edged boards must pass in a transverse or sideways direction through a battery of saws that precisely end-trim (PET) the lumber to prescribed lengths.
A defect referring to a deviation, flatwise, in a piece of lumber, creating the form of a curl or a spiral.
That portion of the trees or other vegetation in a forest stand below the main canopy level.
Urban wood
Used pallets, wooden shipping crates and clean construction wood diverted from the waste stream and chipped for use in making particleboard and MDF.
Veneer Logs
Although veneer logs are sold by the board foot, they are never converted to lumber. Veneer logs are turned and rotary cut, that is, the wood is peeled off the log by turning it against a stationary knife. the sheets of wood may be laminated into plywood or laminated veneer lumber (LVL) products.
Veneer Sheets
Thin sheets of wood of a specified thickness that are peeled, sliced, or sawn from logs for use in plywood, paneling, and furniture.
Vertical integration
In the forest products industry, a vertically integrated company grows its own trees, makes products from them, then makes other products from fiber leftovers from the initial manufacturing operation, then converts and adds value to all these products.
A lumber defect referring to the absence of wood or the presence of bark along an edge or corner.
A lumber defect referring to any combination of bow, crook, cut, or twist.
Whole tree chips (WTC)
Some mechanized loggers reduce trees that are not otherwise marketable as logs to whole tree chips to be sold to wood energy plants. Whole tree chips differ from mill chips in that they include the bark, sapwood, and heartwood of the tree, as well as branches and leaves (from deciduous or hardwood trees) or needles (from evergreen or softwood trees).
Wood energy plants
Electric generating plants that burn wood chips as fuel to produce steam and electricity. A number of these plants were built in the 1970's subsidized by the federal government and electric utilities when the price of foreign oil rose dramatically.
The proportion of the log converted into lumber is the product that produces the greatest value. The percentage of the log that winds up in as lumber (54-55%), sawdust (4-19%), or chips (27-41%) depends upon: - Thickness of lumber being cut - Skill of the sawyer - Type of headsaw - Saw kerf - Losses in edging, trimming, drying, and surfacing


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