A simple and accessible tool for understanding the fundamental terms related to wood. From the meaning of sapwood and heartwood to the characteristics of texture, grain, and density. A useful resource for professionals, citizens, and students who want to familiarize themselves with the language of the sector.
Operation by which a continuous tape of veneer or thin plies of wood (strips or veneers) are cut parallel to the grain for the following reasons: to reduce their width to a predetermined size, to regularize their longitudinal edges in order to facilitate better lateral matching or to make them suitable for subsequent jointing. Clipping can be performed either on wet or dried state plies.
In plywood, this is the operation through which individual sheets of veneer or strips are temporarily spliced together to form a unit with surface dimensions equal to those of the finished panel in order to facilitate its composition. The most commonly used splicing systems involve a longitudinal loading of pairs of edges to be bonded or their transverse (continuous) loading with subsequent sectioning of the sheet that develops. They involve one of the following operating methods: – gluing using a nylon thread impregnated with hot-melt adhesive that is reactivated by special electrical resistors. The thread is applied in a zig-zag pattern on a single surface across the edges of two adjacent sheets; – gluing of adjacent edges after milling them. It involves the coating of hot-melt adhesive and subsequent passage through a system that allows the sheets to be tightly joined and the reactivation of the adhesive through high temperature; – a system of localised application of ‘glue dots’ on the surface between adjacent sheets, with adequate spacing of those dots along the joint line.
Log intended for peeling or slicing.
In Italian, the specification ‘a lamina’ or ‘di piallacci’ is not used, while in other countries it is used to distinguish it from ‘ad anima’ plywood (core plywood).
Plywood in which all the layers are made of veneers arranged parallel to the panel plane. It is also called ‘veneer plywood’.
Plywood covered with a sliced veneer with decorative characteristics. In technical-commercial language, the term “two side veneered” is also often used to indicate a plywood panel covered with a decorative sheet on both surfaces. In the first case, in fact, the back of the plywood is balanced with a sheet (of sliced or rotary cut veneer and generally of a different species from that used to cover the face) that does not have decorative characteristics but has the function of keeping the composition of the plywood symmetrical.
Nonunified term sometimes used to refer to the operation of gluing a sheet of decorative wood (peeled or sliced) to a substrate usually consisting of a wood-based panel.
The operation by which a piece of solid wood or a panel is covered by gluing with a decorative ply or with several plies variously juxtaposed to accentuate the decorative effect: the resulting product is a veneer. The term also refers to the sheet or set of sheets that appear on the better face.
Wood-based panel to whose surface one or more sheets or films of the following materials have been glued: – resin-impregnated paper; – decorative plastic laminate; – a layer of resin; – metal; – decorative veneer.
Small solid wood element with smooth edges similar to the lamella of mosaic parquet.
Timber sawn at approximate right angles to the growth rings so that observing the cross section they form an angle of 45° or more with either face of the piece.
Shear deformation occurring perpendicular to the direction of the grain, or at least through the grain of a vertical element.
Vessels are cells that in broadleaf trees have the function of conducting water and elemental substances from the roots to the crown. They are cylindrical in shape and are arranged one on top of the other. The passage of fluids from one to the other occurs through perforations in the end walls.
One of the cellular components of a vessel. It is also called “elementary vessel”.
Aperture between one vessel element and another.
Percentage of seeds that germinate when placed in the most suitable conditions with no time limit.
Assortment used in agriculture to support grapevines.
Small power articulated tractor with isodiametric wheels and driver’s seat on the rear unit.
Natural forest not altered by man.
Rheological characteristic of the mechanical behavior in materials such as wood that exhibit both elastic and viscous behavior simultaneously. As a result of this: – the duration of loading affects the deformations, i.e., if a load remains constant for a prolonged period of time, the deformation tends to increase until it reaches a value approximately double that of the initial elastic deformation. This may result in the failure of the piece under loads less than it is capable of withstanding in a short time; – climatic variations and cyclic or repeated loads affect strain. The correction factors Kmod and Kdef prescribed by Eurocode 5 are used precisely to modify characteristic values or instantaneous deformations in structural design and verification calculations of a wood structure.
A characteristic of a liquid’s properties that reflects its potential to fluidize. Viscosity is generally measured as the resistance to fluidize through a hole of given size from a special cup (Ford cup).
Surface of a sawn timber that will not be permanently hidden after installation in the final product. Decorations, even with opaque finishes, are not assumed to conceal the underlying surface.
All the space in the wood not occupied by woody tissues, secretions, or deposits, e.g., intercellular spaces, cell lumen.
Chemical substances that may be released during manufacturing processes or even from some of the wood-based products. Examples of such substances are terpenes, aldehydes, acetone, benzene and toluene. Some of these substances may be occurring in particleboard and fiberboard or in coatings and finishes. Drying and pressing are critical processes to be monitored in the wood-based panel industry.
Term used to refer to any liquid other than water that has the specific property of evaporating rapidly at environment temperature and normal atmospheric pressure.
A term of a purely commercial nature, it stands as an element of distinction from the competitors. It generally attests that the product has characteristics that go beyond what is required by any mandatory standards.
Agreement between two partner countries with which both undertake to collaborate in support of the FLEGT action plan and to implement the FLEGT licensing scheme.
Rigid coating consisting of a top layer (thickness <2.5 mm) of wood veneer and one or more layers of other substrate material of mass <75%.
Woody particle about 3 cm in length obtained from a blade cut executed parallel to the direction of the grain. The length and thickness of the wafer are controlled; its width is variable. It generally corresponds to a thick flake.
A wood-based panel produced by reassembling particles (wafers) glued together at high temperature and pressure. Generally, these particles are randomly oriented during deposition (“mat formation”) in order to obtain a finished panel characterised by a greater isotropy of its mechanical properties. However, they may also be oriented along a single direction (oriented waferboard) in the case of enhancing its structural characteristics along a preferential direction.
Railway vehicle used for transporting goods.
Covering made of woody material, mostly for decorative purposes.
Wood species Scientific name: Juglans regia L. Origin: South Europe, from the Caucasus to Japan.
The original curved surface of the trunk, with or without bark, present on any edge or face of a sawn timber. The term ‘trim’ also refers to the strip of wood that is obtained during the trimming operation.
Portion of wood that is obtained when a woody material is cut to regularize its edges. See “wane”.
Arris with a wane in one or more segments.
Generic term used to refer to any variation in a wood-based product relative to its flatness; it includes cup, bow, crook, twist or a combination of these and may occur during processing, drying or storage; it is typically caused by incorrect drying or stacking (poorly arranged laths, etc.), or the presence of anomalies (reaction wood, etc.).
Portion of irregularly growing plant tissue.
Attitude of a preservative treatment to be either removed by the action of water, or to become permanently fixed in the wood (non-washable treatment).
See “siricides”
Any substance or object which the holder discards or is required to discard.
Timber that is not suitable or that is not usable as a result of specific processing.
Determination of the amount of water absorbed per surface unit, as a function of time, at certain conditions of pressure and ambient temperature, by a sample whose surface is in contact with water.
The ratio, expressed as a percentage, between the mass of water content in wood and the mass of wood in its wet state. Water content differs from wood moisture content because the latter refers to the mass of anhydrous wood.
Substance or product resistant to water and high humidity.
Product or bonding able to be affected in a limited way by the effects of exposure in a high humidity environment or in direct contact with atmospheric precipitation or water.
Preservation of logs immersed in water or placed under the action of the stream of special watering cans.
Preservative containing water-repellent products.
Treatment intended to reduce moisture absorption by wood.
Dryer equipped with special nozzles for nebulising the water necessary for process management and control.
Aqueous preparation of a chemical, or mixture of chemicals, intended for wood preservation (includes solutions and emulsions).
State in which the wood is completely saturated with water.
A term used to describe materials bonded with highly resistant adhesives that can withstand prolonged exposure to particularly severe environmental conditions without damage or compromising the bond. A typical evaluation criteria is resistance to boiling water.
Bonding able to withstand, without particular product delamination problems, exposure in an installation environment characterized by high humidity conditions.
A peculiarity of wood whereby the main anatomical elements (fibres or tracheids) are more or less regularly undulated in relation to the longitudinal axis of the trunk. It can result in highly valued figurative effects (e.g. so-called ‘fiddle back figured wood’).
Coating material applied to provide better workability.
Substance incorporated into a recomposed panel to reduce its ability to absorb moisture.
Material of uniform thickness between successive joints or surfaces of an element on which wear occurs.
Breaking strength value determined following a wear/abrasion test.
Mechanical and physicochemical (but not biological) effect detectable on wood or wood products determined by exposure to weathering such as sunlight, wind, dust, heat, and moisture changes.
Wood, plastic or aluminum tool with two weakly converging faces. It is used to assist the landing of a tree in the felling operation and, in some cases, to keep the cut open in the sectioning stage. Steel wedges are used to split wood.
Insects belonging to the order Coleoptera. Some species attack degraded wood by fungal action.
Measure of the amount of round wood based on its mass (usually calculated in tons).
Wood weight measured in the wet state, i.e. a short time after felling.
Wood species Scientific name: Millettia laurentii De Wild. ATIBT nomenclature: Wengè. Origin: West and East Africa.
Wood species Scientific name: Bombax buonopozense P. Beauv. Origin: Tropical West Africa.
Wood species Scientific name:Tsuga canadensis Origin: Eastern North America
Wood species Scientific name: Tsuga heterophylla (Raf.) Sarg. Origin: North America; cultivated in UK.
Wood species Scientific name: Tsuga heterophylla (Raf.) Sarg. Origin: North America
Wood species Scientific name: Betula papyrifera Marsh. Var., Betula commutata (Regel) Fern. Origin: North America
Wood species Scientific name: Pinus monticola Dougl. Origin: Western regions of Canada and the United States.
Difference between the dry and wet bulb temperature of a psychrometer. From it, the relative humidity of the circulating air (RH) and the equilibrium humidity of wood (EU) can be determined.
Temperature measured by the wet thermometer of a psychrometer. Note: The air velocity around the wet bulb must be at least 1.5 to 2.0 m/s.
Plywood whose plies were sprinkled with glue before drying.
Formation of a fiber mat from an water suspension of the fibers.
Fiberboard having moisture content higher than 20% at the forming stage.
Wood rot caused by a wide range of fungi, including brown rot, white rot and soft rot, but specifically excluding dry rot (brown rot caused by Serpula lacrymans). NOTE 1: In the German language, wood rot caused by the dry rot fungus is also called ‘wet rot’.
Strength of a bonding or material measured after immersion in a liquid for a time and at a specified temperature and pressure.
Condition of a surface that determines its ability to attract a liquid and affects its absorption, adsorption, penetration, and spreading.
Beetle of the family Oedemeridae. Its larva digs into damp, decayed wood, particularly in docks, harbour buildings and wooden barges.
Distance between the center planes of wheels having the same axis or between the center planes of crawler tracks.
See “wheeled tractor”.
Tractor with pneumatic wheels in which steering can be done by rotation of the wheels (front or front and rear) relative to the vertical axis (steerable tractor) or by rotation in the horizontal plane of the front unit relative to the rear unit (articulated tractor).
Medium-sized pith patches (e.g. in beech).
Insect hole in which the walls are the same color as the surrounding wood and not blackish in color.
Wood species Scientific name: Populus alba L.