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.
Set of small branches of wood, mostly for firewood, usually held together or tied.
A physical, morphological or growth particularity of timber that may influence its use but does not constitute a defect for a particular processing.
Physical, morphological or growth characteristic of wood that could affect its use.
A motorised system that guides material through an operating machine (e.g. a debarking machine or head saw) at a constant speed.
Machine (or part of it) specialized for tree felling.
See “feller”.
Stage of the felling operation during which the tree, cut off at the base, falls or is dropped to the ground by employing tools such as: wedges, felling lever, peavey, zappie, manual tackle.
Operation in forestry that consists of two stages: the cutting of the stem at the bottom and the landing of the plant.
Direction in which the landing of the tree is directed in the felling operation.
Special portable frame to which a small lightweight chainsaw is attached at the bottom. It allows, while standing upright, the felling of small stems on level ground.
Hand tool consisting of a special lever used to assist the operator in landing small and medium-sized plants. It replaces wedges.
Large two-handed saw used in the past for cutting timber in a forestry context.
Year or season in which a tree was cut.
Split caused by felling of the plant. It originates on the base end grain and extends longitudinally.
See “felling shake”.
Point where a tree has fallen or been cut down.
Tool for assisting the felling of trees during thinning of young dense stands of conifers.
Machinery used for felting fiber bundles.
Operation of controlled distribution, by mechanical or pneumatic system, of a set of fibers deposited to form a mat (which specifically is also called “felt”). In the case of particles, it is called “forming.”
Portion of the Oak cork’s bark from which, after the first cut, more elastic, smooth, light and easily workable cork is produced. It is usually collected at 8-10 year intervals.
A machine’s device for maintaining the width or thickness of the workpiece.
Durable coating for plywood consisting of glass fibers combined with resins. These coated (composite) panels are also often used for truck and trailer bodies, containers, and concrete formwork. Seamless panels at least 12 meters long can be produced as side walls or trailer roofs.
In anatomy it indicates a specific constituent of deciduous wood, relatively long (1 to 7 mm), narrow and thin, fusiform in shape, and lacking apical openings. In the standing tree it constitutes tissues with a predominantly supporting function. As a general term, however, it denotes a structural cellular element of elongated cylindrical shape and is also applied to coniferous wood. When these elements are disaggregated by chemical and/or mechanical action, as in the case of defibering, they can be reassembled in the form of fiber panels. In papermaking, fibers are delignified and further refined to their fibrillar structure.
Group of elongated cells of wood or other fibrous materials held together by a natural binder (lignin). They maintain a fibrous appearance and are suitable for forming a felt for the production of fiberboard. Fiber bundles can also be used to produce shaped objects by molding.
Theoretical condition in which the cell walls of wood are completely saturated with moisture and at the same time there is no water in the liquid state within the cell lumen. By international convention, the saturation point (also called the “cell wall saturation point”) is assigned a wood moisture value of 30 percent (percentage referring to the weight of anhydrous wood).
Fiber-shaped tracheid usually with thick walls and small lumen, pointed apices, areolate pi pairs and lenticular to slit-shaped orifices. This term is applicable to late wood tracheids of gymnosperms as well as to fibriform tracheids of woody angiosperms.
Wood-based panel formed from wood fibers or other lignocellulosic materials (flax, hemp, kenaf). It is produced by felting the fibers and consolidating them, usually after the addition of adhesive, by applying temperature and/or pressure. Bonding derives: – Either from the felting of the fibers and their inherent adhesive properties (in fact, lignin is a chemical compound containing aromatic and phenolic radicals); – or from the addition of a synthetic adhesive to the fibers themselves. Fiber panels are classified according to their density and method of manufacturing. a) Hardboard (hardboards). These are panels with a density between 500 and 1200 kg/mn that often include other materials to improve their properties. Wet-process hardboards involve the formation of a mat of wet fibres and their subsequent moisture reduction before hot-pressing on a fine-mesh mat; dry-process hardboards are made very similarly to MDF, using a phenolic resin as an adhesive. b) Insulating panels. Uncompressed fibre panels with a density of 400 kg/mn or less. c) Medium density fibreboard (MDF). Dry-produced fibre panels, of a density between 500 and 800 kg/mn. They are normally manufactured using a urea-formaldehyde-based adhesive and are mainly used in furniture or similar applications.
Vascular element of relatively small diameter. It shows a resemblance to a fibro-tracheid.
Strand-shaped component of the wood cell wall, visible under a microscope.
Angle between the longitudinal axis of the cell and the direction of fibrils in the cell wall.
See “fiddle back figured wood”.
Fiddle back figure is an aesthetic effect due to irregular undulation of the grain. It appears on the surface of a sawn timber or a veneer as a succession of thin, regular and highly flattened transverse bands, which are shiny and opaque due to the different angle of incidence of light in relation to the direction of the fibres.
Close, transverse stripes caused by wavy grain that are visible on the surface of a sawn timber.
The pattern produced on the surface of the wood by growth ring marks (which appear different depending on how they are cut), parenchymal rays, knots, deviations of the grain from its natural condition and irregular colouring. Note: When they have decorative value they are prepared as figured veneers as opposed to flat-coloured veneers.
See “figure”.
In a broad sense: any blade maintenance operation involving adjustments and changes in tooth profile, size, and arrangement. In a narrow sense: routine blade maintenance operation by which chamfers in the teeth due to wear are removed.
Machine used for filing and grinding blades.
A low-cost additive used in the formulation of an adhesive mixture intended for bonding plywood or a wood-based panel. It is added for the purpose of controlling penetration and reducing the cost of the adhesive (resin). A filler differs from an excipient because it does not have adhesive properties. Examples of fillers include: calcium carbonate, vegetable shell flours (from coconuts, hazelnuts,) etc.
Repair by filling open defects with a synthetic filler.
A coating that can be applied to planed wood surfaces of coniferous (e.g. larch, spruce) and ring-porous hardwood species (e.g. oak). The continuous coating film can be felt and measured on the wood surface and has a dry thickness of approx. 20 ?m. Note: with species with diffuse porosity (maple, beech…) continuous coating films can be obtained with lower dry film thicknesses.
Plywood covered with a cellulosic fiber-based sheet impregnated with resin or a resin layer applied directly to the surface of the panel. Generally, the most commonly used resins are phenolic or melamine type.
Wood moisture at the end of the drying process.
The condition of the timber at the end of seasoning and conditioning treatments.
Vacuum applied at the final stage of the pressure process to recover excess impregnant from the wood and facilitate subsequent drying.
Texture characterised by the presence of relatively small cells and/or relatively narrow and regular growth rings.
Very tiny particles with a powder-like appearance. They are generally discarded, but sometimes used in the outer layers of the panel to achieve a smooth surface or are added to an adhesive as a filler or to prepare a synthetic filler.
In a finger joint, it is the inclination angle of each side of the finger.
System whereby two semi-finished products or wood-based panels are joined together with adhesive, after milling of the jointing edges, in order to obtain a complementary finger-like or mini finger-like profile.
Wooden element obtained through finger joining, generally glued, which connect the pieces in the direction of their length. It is thus possible to obtain semi-finished products of long length (“lath”) that can be used in the production of glulam.
It is the distance between the base and the tip of the finger, measured along the centerline of the finger.
The optimal category for certain qualification standards, indicating timbers suitable for finishing in their natural state or with varnish.
Element whose face has been factory treated.
Thickness achieved as a result of planing.
Treatment of the surfaces of a semi-finished product or wood-based panel with paint, varnish or impregnating agent in order to protect them, change their color or highlight their decorative characteristics. The term is also often used to refer to the grading and sanding operations that precede the above treatments. Finishing treatments for the use of semi-finished products in outdoor environments minimize the action of weathering that makes the surface of untreated wood rough and erodes. Different finishes result in different levels of protection, so the type of product, quality, quantity and degree of application must be carefully considered in relation to the intended objectives. Recommended finishes for structural panels used outdoors include, for example, semi-transparent impregnants, pigmented impregnants and acrylic latex paints. In contrast, recommended finishes for the same panels used indoors include oil-based paints, latex paints and impregnants.
Treat timbers or other combustible materials with retardants aimed at reducing the danger of fire.
Tendency of a material to spread fire in case of radiant heat and/or ignition flame. In this regard, a special “Fire Reaction Classification and Approval of Materials for Fire Prevention Purposes” (Ministerial Decree of June 26, 1984, Ministry of the Interior) is applied. It distinguishes materials into five different Fire Reaction Classes, from Class 0 (valid for incombustible materials) to Class 4 (typical of easily flammable materials). The parameters used for fire reaction classification are flame spread rate, post-combustion time, dripping, etc. As far as wood-based materials are concerned, these can reach Class 0 in the case of particle or fiberboard made of wood and cement and Class 1 in the case of wood-based panels (plywood, particleboard) specially treated with fire retardant substances. Normally wood and other derived materials are classifiable in the lower Classes depending on their thickness and the type of installation (wall, ceiling, floor).
Period of time in which a material or structure (door, wall, ceiling) is able to provide a level of protection against fire under specific test conditions, while continuing to guarantee its functionality and performances of various types (resistance, emission of combustion fumes and thermal insulation). In this regard, the REI index is generally used, followed by the fire resistance value expressed in minutes.
A chemical substance or mixture of substances used to reduce the flammability of a material or retard the propagation of flame along its surface.
A product or mixture of chemicals that, along with its preservative function, also has a dampening or retarding action on wood combustion.
Treatment intended to improve the wood’s reaction to fire.
Portion of a log, usually obtained by ‘splitting’, used to feed the flame and heat production in a wood boiler.
Wood (round, split, sawn, slash, etc.) intended for use as fuel.
Nonunified term sometimes used to refer to strips of less length than the length of the log being processed that can be recovered during rotary cutting from the early stages of log peeling until it results in a perfect cylinder. They are generally obtained by veneer clipping and docking for the composition of the inner cross-fiber layers of plywood.
Longitudinal separation of the main anatomical elements (fibers or tracheids) that does not affect the entire thickness of the semi-finished product. In the case of plywood, the sheets that make up the two outermost sheets of the panel are considered. Note: More properly we should speak of “crack” when referring to the way the phenomenon appears along a longitudinal direction, and of “fissure” when considering the phenomenon as it appears on a cross section.
See the note in “Fissure”.
A panel smaller than the standard panel used for the sheathing.
The act of fixing a preservative in timber to prevent leaching. NOTE: Fixation occurs either by conditioning the treated wood under environmental conditions or by exposing it to artificial conditions that accelerate the rate of fixation.
Ability of an impregnating compound to become completely or partially insoluble in water after its application to wood so that leaching is greatly reduced.
A thin, flat woody particle of uniform thickness whose direction of the grain is contained in the plane of the flake. It is thus assimilated to a small rectangular piece of sheet, sometimes square and sometimes more elongated in the direction of the grain than perpendicular to it. It is produced by cutting logs or their parts or solid pieces of wood of any shape. Typical dimensions of a flake can range from 0.25 to 0.50 mm in thickness and between 12.5 and 37.9 mm in length; width varies according to use. Some variants of flake are known by the terms “wafer” (used to indicate flakes of greater thickness and sometimes length) and “strand” (used to indicate flakes of reduced width). Flakes are used with appropriate adhesives to reconstitute woody materials (flakeboards) of various shapes and densities.
1) A particleboard whose better face is characterised by an appearance like cotton flakes or frayed flakes. 2) Panel made entirely of particles having the appearance of cotton flakes.
Figure in which the pattern given by the grain of the wood appears as parabola segments closed towards the end. According to another definition, the term is also used to indicate a veneer in which the traces of the growth rings are oriented at an angle of less than 45° with its surface for more than half the width of the piece.
Spreading (propagation) of a flame from an ignition point along the surface of a liquid or solid or across the volume of a gaseous mixture.
A cut executed in proximity to the workpiece periphery, roughly tangential to the growth rings (often resulting in flamed figures).
Timber sawn approximately parallel to the growth rings so that observing the cross section all or some of the growth rings form an angle of less than 45° with either face of the piece.
Veneer resulting from a cut tangential to the direction of the growth rings and perpendicular to the rays.
Boards stacked in such a way that their faces lie in a more or less horizontal plane.
Forest Law Enforcement, Governance and Trade Licensing Scheme (FLEGT) is the licensing system for the export of wood products from partner countries and its implementing provisions on border controls.
Document based on the shipment or market participant, in a standardised, forgery-resistant, tamper-proof and verifiable format, referring to a shipment as complying with the requirements of the FLEGT licensing scheme, duly issued and validated by the licensing authority of a partner country. The licensing, registration and reporting systems may be paper-based or electronic, as appropriate.
Legally produced timber from legally harvested national timber or timber legally imported into a partner country in accordance with the national laws established by that partner country as defined in the Partnership Agreement.
Large piece cut by sawing lengthwise from the side of the trunk (thus without the area affected by the pith, i.e., the heart), further squared on two or more sides and intended for further processing.
Roughly sawn woody assortment that includes portions with bark and is intended for subsequent slicing processing.
Timber that can be harvested by flotation and is capable of floating due to its density.
A particular method of timber harvesting using watercourses.
Non-structural floor layer not connected to the underlying structure.
Any laying system in which elements are attached to each other but remain independent of the underlying surface.
Wood flooring installation system in which the individual elements are assembled together but not fixed to the supporting surface.