The Lumber and Building Material Industry is vast, with many disciplines and definitions. Below are just a few terms that may assist you in finding the right product for the right project, or simply satisfy general curiosity. Don't hesitate to contact us for further explanation and insight.
A sanded plywood panel with an A-grade face, a C-grade back and C-grade inner plies. This is bonded with exterior glue.
Driving forest management with scientific research. This requires excellent monitoring, and feed back loops to quickly put new knowledge into practice on the ground.
The combined production of both crops and trees to maximize water efficiency.
Seasoned without artificial heat. This method uses the atmosphere / air to naturally dry lumber.
This is usually abbreviated with “&Btr” and is a grade of lumber signifying that an unspecified percentage is a higher grade than the lowest acceptable grade. For example, Std&Btr grades will contain some pieces of Standard Grade and some pieces of higher grades, such as Construction.
The kind used in wood preservatives, not to be confused with commercially produced Trivalent Arsenic, which is not used in any wood preservative. Pentavalent Arsenate occurs naturally in the soil, water, air, plants, and in most living creatures - including humans.
Establishing a new forest by planting seedlings or by direct seeding (as opposed to natural regeneration).
A decorated piece of lumber with a raised half-circle bead along the length.
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Developed in 1938, the application of an initial vacuum followed by the impregnation of creosote formed a basis for the present wood-treating industry.
This is the standard unit of measure for lumber. One Board foot is equal to a 1 inch thick board 12 inches in width and 1 foot in length.
single layer of cells between the woody part of the tree and the bark. Division of these cells results in diameter growth of the tree through formation of wood cells (xylem) and inner bark (phloem).
The forest cover of leaves, branches, and foliage formed by tree crowns. There may be several canopy layers.
The trim around the top and sides of windows and doors.
This is the standard grade of plywood sheathing used for various applications, including roofing. The “C” represents the grade of the front and the “D” represents the grade of the back. The “X” represents exterior glue has been used to adhere the plywood layers. However, this exterior glue will only withstand incidental exposure to weather.
A piece of patterned lumber that is tongue and grooved to be used on ceilings, predominantly in older homes. (Beaded Ceiling)
This is the primary material of wood cell walls and it is 100% non-soluble glucose. Cellulose is a polymer chain carbohydrate (i.e. chains of sugar molecules, or polysaccharide) and is the main constituent of the cell walls of all plants, accounting for about 50% of the dry weight of wood. Also, the basic raw material (chemical compound) used in papermaking. It is the most widely distributed organic (carbon-based) compound. It is not water soluble and is extracted by pulping.
Third party certification might reassure the end consumer of wood products that the wood was produced and processed in a 'sustainable' manner, without damaging forest ecosystems. Certification tells the consumer that the wood is coming from a well managed or 'sustainable' forest operation where good stewardship is practiced.
Consumer Information Sheet, guidelines for handling treated wood, available to the consumer at retail outlets where treated lumber is sold.
A water-borne solution most commonly used on lumber, plywood, and timbers. This preservative protects against insects (primarily termites), fungi, and marine borers. CCA is the most widely used of all pressure-treating wood preservatives.
A grade of lumber that signifies being practically free of all blemishes or defects. This is a very select grade of lumber.
In a clear cut, all the trees in a block are harvested so that a new crop of sun-loving (i.e. shade intolerant) trees can get off to a fast start. Clear cutting also facilitates mechanical planting. In some stands of trees a clear cut follows one or two "selective cuts" which thin out the trees that compete for sunlight, water, and nutrients. Today, clear cuts are smaller in size and are designed to blend in with the landscape. Many animals, such as deer, depend on clear cuts - which provide excellent forage. Clear cuts are prohibited next to streams and lakes which require buffer zones with selective harvesting, if any.
This is the highest grade of Redwood. This grade is usually used in finish work were the finest appearance is desired.
A forest community that represents the final stage of natural forest
Cone-bearing trees having needles or scale-like leaves, usually evergreen, and producing wood known commercially as 'softwoods.'
The sustainable use of forest resources in a manner that does not degrade the collective resource values of a region over the long term.
This is Redwood that consists of all heart with no sapwood. This grade has a high resistance to insects and decay so it is often used in applications where it will be exposed to the elements.
Any deviation in the edge based on a straight line from end to end of a piece of lumber. (Considered a warp)
This is the upper part of a tree. This also is the term for a slight camber on a horizontal member. The crown is generally placed to the top.
A flatwise deviation from a straight line across the width of a piece of lumber, measured at the point of greatest distance from the line
This is a groove cut into one piece of lumber to accommodate another piece of lumber. This is usually cut across the grain rather than a “rabbet” which is cut with the grain. This also is the term used for the lower part of an interior wall.
The diameter of a tree as measured at breast height. Standard dbh is measured at 4.5 feet above the ground.
Decomposition of wood by wood-destroying fungi.
Term applied to trees, commonly broadleaf, that usually shed their leaves annually. It is an adaptation to prevent excessive water loss by transpiration when water is scarce. Also known commercially as “hardwoods.”
This is the separation of the layers of plywood at the glueline. This is usually caused by moisture or defective glue.
When a piece of lumber has been passed through saws so it is smoothly trimmed at both ends. Typically this is done in two feet increments – 8’, 10’, 12’, etc.
When is seasoned to a moisture content of less than 19% either by kiln or air.
Wood that is to be dried by applying heat and therefore withdrawing moisture is put in this chamber.
Vertical grain; a cut so the wide surfaces are at right angles to the growth rings. Also, the grain produced on quarter-sawn wood. Also, veneer cut within 45 degrees of the radius of the log and across growth rings.
Lumber that has a tongue at one end and a groove at the other. This provides a tight end to end fit between pieces.
Plants that re-sprout following a fire or endure the effects of fire.
Chemical "wastes" which are stored in the heartwood of trees providing natural durability.
This is a particular type of shingle with a machined butt end. These are used mostly used on sidewalls of buildings to form patterned designs.
The hardware (e.g. nails, screws, bolts, joist hangers) used to secure treated wood. Since treated lumber is used for durability, fasteners should be hot-dipped galvanized or stainless steel, especially with water borne preservatives, which contain corrosive salt.
In papermaking this refers to the cellulose fiber. Softwood trees produce long cellulose fibers that are good for strength and hardwood trees produce short fibers that are good for smoothness. Fibers are often blended to create the ideal characteristics for a given paper.
This is a process of joining two pieces of lumber end-to-end by sawing the ends so they can be interlocked. When the pieces are glued and pushed together they form a strong joint.
A chemical applied to lumber or other product to deter the combustion of fire and flame spread. Also, a chemical used to fight forest fires.
The chemical process in which the preservative metals in water-borne solution react with and bond to wood fiber molecules.
Foresters manage forests for the maintenance and reoccurrence of desirable conditions. What is desirable is determined by social, biological, and economic considerations.
The art, science, and practice of managing forest landscapes to provide a sustained production of a variety of goods and services for society.
Rings formed annually that are at less than 45 degrees with the surface of the piece of lumber.
This is a tongue and grooved piece of lumber usually in 1”x4” dimensions. It is sold as either flat grain or vertical grain and usually in Superior and Prime grades.
A machine with a crane which can load logs onto its chassis and piggy-back them to a road where it can sort and pile them or load them directly onto a truck.
Lumber that when sawn excludes the heart center or pith of a log. This will help prevent checking and cracking.
Most lumber is marked with a grade by the mill. It is graded for quality and / or use and stamped accordingly with a grading association or agency stamp.
This is lumber that is unseasoned and not dry. Lumber with a 19% or more moisture content.
A narrow channel on a piece of lumber or plywood usually on the edge or face.
A deciduous or broadleaf tree; also applies to the wood from such trees.
This is the inner / dormant part of the tree contained within the sapwood. Only the outer part is the living part and needed to survive.
Shakes, usually cedar, that are 3/4'” to 5/4” thick at the butt end.
Perforating the wood surface with small slits to improve the penetration and effectiveness of the preservatives. Not necessary with treated Southern Yellow Pine, Ponderosa Pine, and Red Pine.
Pertaining to plants or animals that are native to a particular region or country.
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Wood that is Kiln-Dried after Treatment. Pressure-treating with water-borne preservatives adds moisture to the wood, which can be removed by kiln-drying.
Lumber, seasoned / dried in a kiln to a certain moisture point.
A spot on a piece of lumber, after being sawn, where a branch or limb had once grown. They are classified by quality, occurrence and size – the smaller is generally considered better in the grading process. (e.g. Pin Knot – 1/2” or smaller, Small – 1/2”-3/4”, Medium- 3/4"-1 1/2'”, Large – over 1 1/2") See knot occurrence and knot quality.
a very strong type of wrapping paper made from a special type of chemically treated wood pulp. The Kraft (Sulfate) pulping process produces the best quality softwood pulp. Generally brown natural kraft but can be bleached white. Kraft is the German word for strength.
Knots are classified by size, quality and also by occurrence on a piece of lumber. (E.g. Branch Knots, Corner Knots, Cluster Knots, Single Knot, Spike Knot) See knot and knot quality.
Knots are classified by the quality of the knot along with the size and occurrence. Quality grades are determined by soundness, advanced decay, pith holes and other variables. See knot and knot occurrence.
Veneers laminated together to form a large structural piece of lumber. Similar to a very thick piece of Oriented Strand Board (OSB) used for long spans where upright support beams are not feasible or desired.
Used as backing for wall plaster or other material, this is a thin, very narrow wooden strip.
A small moulding (S4S) used predominately in trellis work.
A polymer that binds cellulose together to make wood. The stiffening material inside wood cell walls that gives them strength and rigidity. Allows trees to grow tall and out-compete other plants for sunlight. This accounts for about 30% of the dry weight of wood. Lignin is removed in the pulping and bleaching processes to brighten the paper and prevent yellowing.
The weight of water in wood, expressed as a percent of the oven-dried weight of the wood.
The practice of managing forest resources for a variety of simultaneous uses and benefits including water, forage, wildlife habitat, wood, recreation, wilderness, and minerals.
National Environmental Policy Act (1969) requires Environmental Assessments (EA) and Environmental Impact Statements (EIS). This act is the basic national charter for protection of the environment in the U.S.
This is the size designation for most lumber and wood products. It is usually greater than the actual size. For example a 1”x6” piece of lumber usually measures 3/4”x5 1/2" after it is surfaced.
a resource that is in limited supply and doesn't have the capacity to be replaced through natural processes, at least not for many thousands of years. Fossil Fuels are a nonrenewable resource.
To most people "old growth" means big trees. The U.S. Forest Service definition is "a forest with trees 200 years or older, snags (standing dead trees), and down woody debris on the forest floor."
Plywood that has a surfacing material added to it (either on one side or both). Usually, this is to create a protective or decorative surface for finishing. These may include resin film, impregnated paper, plastics, or metal.
A grade of a wood product that signifies it is more suitable for painting rather than a clear finish. Paint Grade Spruce (PGS).
This restricted chemical is usually applied under pressure to help in preserving wood. Oak Railroad Ties are often Penta treated.
A layer of plant tissue just inside the bark that transports food (dissolved nutrients) from the leaves to the stem and roots.
Complex process that takes place in cells of green plants. Radiant energy from the sun is used to combine carbon dioxide (CO2) and water (H2O) to produce oxygen (O) and carbohydrates (such as glucose) and other nutrient molecules.
A knot with a diameter no larger than 1/2”.
The accumulation of resin in wood cells in an irregular patch graded as light, medium, heavy or massed. This is also the term for the angle of a roof on a house.
A flat panel made up of a number of layers. The layers are thin sheets, or veneers, of wood. The grain of the wood for each layer is at a right angle to the adjacent layer of wood creating added strength. The layers are bonded together.
Any substance applied to wood that is effective in preventing the development and action of wood destroying fungi and insects.
ACA: Ammoniacal Copper Arsenates
ACC: Ammoniacal Copper Citrates
ACQ: Ammoniacal Copper Quaternary
ACZA: Ammoniacal Copper Zinc Arsenates
CCA: Chromated Copper Arsenates
PCP: Pentachlorophenol (Penta)
The process by which preservatives and/or fire retardants are applied to wood products. The treatment involves forcing the chemical, and sometimes water sealant, deep into the cellular structure of the wood under high pressure in a closed cylinder.
To saw a log into quarters lengthwise and then into boards in order to show the wood grain to advantage. This shows the annual rings at angles of 45-90 degrees with the surface of the piece.
This is a rectangular cut where two surfaces are cut on the edge of a member, parallel with the grain.
Lumber of various lengths that are usually in two feet increments. A random length loading is presumed to have a fair representation of the mills production.
Lumber of various widths.
Sequoia sempervirens is found in limited areas of Northern California and Southern Oregon and is naturally resistant to decay. It is used in many of the same applications as Cedar, especially siding and paneling. Sequoia gigantea is another species that grows in the Sierra Mountains of Central California and is protected from harvest.
The renewal of vegetation by natural or artificial means.
Wood species that are difficult to treat. These species must be incised prior to treatment to meet AWPA standards.
This is a resource that has the capacity to be replaced through natural processes. Trees are a renewable resource.
This is a siding pattern where wider boards are nailed over the battens, giving a narrow inset. Rip – To cut a board along its length versus a cross cut along the width.
Term used for lumber that is not dressed or surfaced. The surface is the same as when it was first sawn from the mill. Surfaced lumber is referred to as smooth.
Lumber that has been run through a planer with notched knives. It has a rough sawn texture, but it is accurately sized.