"A" thru "R" Industry Definitions

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).

 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.

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.

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.

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.

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.

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.

 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.