Glossary

A slight, intentional curve or upward arch built into a structural element—usually a beam, joist, or lintel—to counteract deflection under load or improve appearance.

A thin layer of tissue between the bark and wood that repeatedly subdivides to form new wood and bark cells.

A projecting structural member that is rigidly fixed at one end, with the other end extending freely beyond its support.

Measures moisture content by sending a low-frequency electromagnetic field into the timber and sensing changes in capacitance (how the material stores electrical energy), which correlates with moisture levels.

Any natural or artificial system that absorbs and stores more carbon dioxide (CO₂) from the atmosphere than it releases, helping to reduce the effects of climate change.

A drying defect characterised by the presence of compression stresses in the outer zone and tensile stresses in the core. It occurs when rapid drying has caused permanent set of the outer zones of a piece of wood and when the outer layers of timber dry and shrink faster than the inner core, causing internal stresses that can lead to problems during machining or further drying.

A natural, water-based adhesive created from milk protein (casein), known for its strong bond, good water resistance (when properly formulated), and long open time for assembly. It was historically used in plywood manufacturing and has some resistance to water but is not waterproof.

It’s a visual grain pattern formed when wood is flat-sawn (also known as plain-sawn). It is created by cutting tangentially to the growth rings of the log which exposes curved growth rings in the surface, producing the characteristic arched pattern.

Copper Chrome Arsenate, a chemical wood preservative used to protect timber from decay, termites, fungi, and other biological hazards.

In wood anatomy, a general term for the minute units of wood structure that have distinct walls and cavities, including wood fibres, vessel segments, and other elements of diverse structure and function. In dense hardwoods, the fibre cells are thick walled and make up a major part of whole zones of wood. These fibrous zones dry slowly. The arrangement, size, and type of cells affect wood properties like strength, durability, density, grain and texture, moisture movement and drying behavior.

Wood cells are mostly made of:

• Cell walls (composed of cellulose, hemicellulose, and lignin)
• Lumen (the hollow central cavity that may carry water)

The carbohydrate that is the principal constituent of wood and forms the framework of wood cells.

Forest certification refers to the assessment of forest management by an independent third party auditor according to performance criteria for sustainable wood production. The certifications recognised in Australia are:

Responsible Wood is a Standards Australia accredited standards development organisation and is the representative of the Programme for Endorsement of Forest Certification (PEFC) in Australia. The Forest Stewardship Council (FSC) is a non-governmental, international organisation that is dedicated to promoting the responsible management of the world's forests. Find out more about certification and responsible sourcing here.

The documented process of tracking wood or wood-based products through every stage of the supply chain—from the forest of origin to the final product—to ensure they come from responsibly managed forests.

A separation of fibres along the grain forming a fissure but not extending through the piece from face to face. Checks commonly resulting from stresses built up during seasoning. They run radially, across the growth rings and are a lengthwise separation in the wood, typically starting at the surface and extending along the growth rings, caused by the wood shrinking unevenly as it dries.

A wedge-like, sharp-edged tool used for cutting or shaping timber.

Especially in timber or steel framing—a chord is a primary structural member that forms the top or bottom edge of a truss, beam, or structural framework. The term also applies to beam flanges or the perimeter members of a plywood diaphragm.

The external layer or material applied to the outside of a building to provide protection, insulation, and aesthetic appeal. It acts as a skin or envelope, shielding the structure from weather while contributing to its visual appearance. Timber cladding includes natural or treated timber boards and plywood.

The clear horizontal distance between the supports of a load bearing member.

A cleavage test measures the resistance of timber to splitting along its grain—specifically in the radial and tangential planes—by applying a force that attempts to separate or split the wood longitudinally.

An architectural feature consisting of a high section of wall that contains windows above eye level, usually located near or at the roofline. Its main purpose is to bring natural light and ventilation into the interior of a building, particularly in large or deep spaces where side windows alone aren’t sufficient.

Wood with narrow, inconspicuous growth rings. The term is sometimes used to designate wood having small and closely spaced pores, but in this sense the term "fine textured" is more often used.

(also known as a lag screw or lag bolt) is a heavy-duty screw with a hexagonal head, designed for joining heavy timber or fixing timber to masonry or metal. It is driven using a spanner or socket wrench, rather than a screwdriver.

Wood with widely spaced and prominent growth rings, which results in a distinct, bold grain pattern. The term describes both the visual appearance and the texture of the wood surface. It is usually caused by fast tree growth and the contrast between earlywood (lighter, less dense) and latewood (darker, denser) becomes more pronounced.

The flattening of single cells or rows of cells during the drying or pressure treatment of wood. Often characterised by a caved-in or corrugated ("washboarded") appearance of the wood surface.

A collar tie is a horizontal structural member used in roof framing to help resist the outward thrust of the roof rafters and prevent the roof from spreading.

A vertical structural element that transfers loads from above (like floors or roofs) down to the foundation.

A force that pushes or squeezes material together, causing it to shorten or compact. It is one of the primary types of stress that materials—like timber, steel, or concrete—experience in structural applications.

A type of structural damage in timber that occurs when the wood is crushed or buckled under compressive stress—usually along the grain.

A fabricated or cast metal bracket into which timber structural members abut, used to joint timber compression elements to other structural members.

A controlled process used to equalise moisture content and relieve internal stresses in timber after or near the end of drying—especially kiln drying.

Conservation is the responsible management and protection of natural resources to ensure they are available for future generations. It involves maintaining the health, biodiversity, and function of ecosystems while allowing for sustainable use where appropriate. In the context of forests, conservation means sustainably managing forests and forest resources to preserve biodiversity (plants, animals, ecosystems), protect soil and water quality, prevent overharvesting and deforestation, ensure long-term wood supply through sustainable yield, and support carbon storage and climate regulation.

A metal connector or reinforcing strip used in timber or steel construction to maintain structural continuity across joints, particularly where elements need to transfer tensile or shear forces.

A planned, intentional gap or groove in a building material—such as concrete, masonry, or plaster—designed to control where cracking occurs due to shrinkage, temperature changes, or movement.

A length of timber laid horizontally on the top of a column to transfer loads and to provide a seat for beams. A compound corbel includes several lengths of timber instead of one.

An adjustment of the readings of the resistance-type electrical moisture meter to compensate for different species of wood. Corrections are tabulated in AS/NZS 1080 1:1997

A defined area of forest, usually with consistent characteristics.

A metal sleeve threaded internally and used to connect threaded rods or bolts.

The slow, continuous movement or deformation of timber (or any material) under a sustained load—even if the load is below the material’s strength limit.

In construction, particularly timber framing, a cripple (or cripple stud) is a short vertical framing member used to fill in spaces above or below a window or door opening, or between a header and top plate or a sill and bottom plate.

A criterion is a category of conditions or processes by which sustainable forest management may be assessed. A criterion is characterised by a set of related indicators that are monitored periodically to assess change. An indicator is a measure (measurement) of an aspect of the criterion. An indicator can be quantitative or qualitative variable which can be measured or described and which, when observed periodically, demonstrates trends.

A cut made across the grain of the wood, typically to shorten the length of a piece of timber.

An arrangement in which the fibres and other longitudinal elements of a piece of wood deviate from a line parallel with the edges of the piece. Cross grain may be either diagonal or spiral grain or a combination of the two.

CLT is an engineered wood product composed of three or more layers of timber boards laminated together, with each layer oriented perpendicular to the adjacent one, providing strength in both directions and excellent dimensional stability.

A method of slicing veneers whereby the average inclination of the growth rings to the wider face is tangential or less than 45 degrees. This method is also known as flat cut.

A shape or structure that resembles a cross—specifically one with four arms extending at right angles from a central point (like a "+" shape).

A concave curvature across the grain or width of the a piece of timber.

To change the properties of an adhesive by chemical reaction (which may be condensation, polymerisation, or vulcanisation) and thereby develop maximum strength.