Glossary

Timber drying rack (in a sawmill) - A unit of timber where each layer is separated and spaced for drying with rack sticks.

Storage rack for timber - A rack is a physical structure used to store and organise timber, often in a warehouse, workshop, or on a construction site.

A racking frame is a load-bearing structural frame built to resist horizontal (lateral) forces that might otherwise cause the structure to deform, twist, or collapse sideways.

A temporary assembly tool or fixture made up of guides and supports that helps maintain correct stick alignment, square sides, and plumb ends during the construction of timber racks or frames.

One of a series of roof support timbers that provide principal support for the roofing material. Rafters usually span parallel to the slope of the roof.

Roughened surface of timber and other wood products, particularly softwood, after planning, caused by the projection of early wood or latewood above the surface.

Rays (also known as medullary rays) are ribbon-like structures of cells that extend radially from the centre of the tree (pith) outward to the bark. They are part of the tree’s natural anatomy and serve to store and transport nutrients across the wood (perpendicular to the grain).

In the context of timber drying, a reconditioner refers to a process or chamber used to treat timber that has experienced collapse during drying, particularly in refractory species. It is usually a chamber into which wet steam (not more than 100°C) is injected for several hours to recondition timber.

Reconditioning treatment involves exposing kiln-dried timber to high humidity and moderate heat (typically using steam or moist air) to equalise moisture throughout the board and relax internal stresses. It is usually applied after drying to restore the shape of collapsed or distorted wood.

A Recorder–Controller is an instrument or device that both:

• Records data over time (Recorder), and
• Controls a process based on input signals or set parameters (Controller)

It is an instrument that continuously records dry- and wet-bulb temperatures of circulated air in a dryer or kiln and regulates these conditions by activating automatic heat and humidification systems. It is used in kiln drying, preservative treatment, and quality assurance.

Recording Function:

• Continuously logs process data such as: Temperature, humidity, moisture content, pressure.
• Stores this data for monitoring, analysis, and compliance.

Controlling Function:

• Automatically adjusts equipment or conditions to maintain desired settings. (E.g. turns on/off fans, heaters, or vents in a timber drying kiln.)
• Uses feedback loops like PID control (Proportional, Integral, Derivative) to fine-tune outputs.

In kiln or veneer drying, a process whereby dried material found to have a moisture content level higher than desired is returned to the dryer for additional drying.

In timber drying this term is used to indicate high resistance to moisture loss during drying. The term refractory refers to wood species or wood types that are difficult to dry without developing defects such as:

• Surface checking (cracks on the outside)
• Internal checking (cracks inside the timber)
• Collapse (cell wall deformation)
• Honeycombing (internal splits)

A regrowth forest is a forest stand composed of young or intermediate-aged trees that have re-established after the original vegetation was removed or significantly disturbed.

A measure of the amount of water vapour in the air relative to the maximum amount the air can hold at a given temperature. It is expressed as a percentage and changes with temperature and atmospheric conditions.

Resins are organic compounds that are either naturally secreted by plants (like pine trees) or synthetically produced to serve as glues, sealants, finishes, or structural binders in wood-based materials.

Resorcinol glue (or resorcinol formaldehyde adhesive) is a high-performance, waterproof adhesive commonly used in the timber industry for structural bonding applications where durability, moisture resistance, and strength are critical.

The surface left exposed when one board is fastened over another; the edge of the upper set slightly back from the edge of the lower.

The persistent echoing of sound within an enclosure after the original source of the sound has stopped, due to repeated reflection between the enclosing surfaces which causes the sound to linger or echo before gradually fading away.

Ribbon figure is a decorative grain effect caused by interlocked grain, producing a striped or ribbon-like appearance—typically visible in quarter-sawn hardwoods like sapele, mahogany, and blackbutt.

The ridge is the topmost line or beam of a sloped roof, where the opposing roof planes intersect, often running horizontally along the length of the roof.

A beam located at the highest part of the roof to support the upper ends of the common rafters.

Refers to the process of cutting timber lengthwise —in the direction of the grain—typically to reduce the width of a board or log.

A long, thin strip of material—usually made from timber, metal, or plastic—that is fixed horizontally across the rafters or trusses of a roof. It serves as a structural support and fixing point for roofing materials like tiles, slates, or metal sheets.

A distinctive grain pattern in the wood that resembles twisting ropes or cords. It appears as long, wavy, and intertwined lines, often with a three-dimensional look.

A type of wood veneer made by peeling a log in a continuous sheet, much like unrolling a roll of paper. It’s one of the most efficient and economical methods of producing veneer, and is commonly used in plywood and engineered wood products.

Rough sawn refers to timber that has been cut from a log but not yet planed, dressed, or smoothed. It retains its coarse, textured surface directly from the sawmill.

Timber that is used in its natural, rounded form—as it comes from the tree—with minimal processing or milling. It is typically debarked but not sawn into planks or boards.

In the context of woodworking and construction, "rout" refers to the process of hollowing out or cutting a groove, channel, or shape into the surface of wood (or other materials) using a tool called a router.