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.
Partially controlled drying, carried out by heating water contained in wood placed in contact with metal electrodes through which radio-frequency (0.1-100 Mhz) electrical power is applied.
See “high frequency drying”.
When the wood species is not or poorly durable and the environmental conditions of application are conducive to biodegradation.
Controlled drying at atmospheric pressure in a mixture of air and steam with temperatures above 100°C which can be used for the majority of the process or only during a terminal period.
See “high-frequency heating (HF)”.
An acronym of the English term ‘high-pressure laminate’, which indicates plastic laminates with decorative properties obtained under high pressure and often used for the coating of wood-based panels.
Part of the stem between the undercut and the back cut left undisturbed during felling. It is used to guide the fall of the plant.
Outer ends of the hinge that correspond to the sapwood area of the stem. In some cases they must be cut during the felling operation.
In yarders, it is a steel rope, driven by a winch normally placed inside the carriage, which has the function of pulling the load below the line, hoisting it to the carriage when loading, and lowering it to the ground when unloading. In most carriages, this function is performed by the mainline.
Localised depression in an external ply of plywood.
Cavity in the heart of round timber, caused by biological agents.
A machine with multi-shaped blades for the removal of damaged parts of veneers in order to replace them with others obtained with the same machine.
Wood species Scientific name: Quercus ilex L. Origin: Mediterranean Regions, North Africa and Minor Asia.
Laminated timber with cross-sectional area in which the laminations are of a single strength class or a specific manufacturer’s strength class.
Certification that a “type” of product or service conforms to a specific standard. It usually refers to the design or prototyping stage and does not guarantee the quality of delivery.
Scientific name: Armillaria mellea Kummer. Fungus belonging to the Basidiomycetes. It causes white rot in wood.
Fiber separations within wood due to drying.
Hook to which a load is attached.
Shear deformation that occurs parallel to the span (thus generally parallel to the timber fibres) and perpendicular to the height of a horizontally arranged timber element (beam, etc.) subjected to bending.
Wood species Scientific name: Carpinus betulus L.
Gluing operation in which an assembly is pressed together by the application of heat (i.e., high temperature).
Conditioning operation whereby panels after their hot pressing are stacked closely on top of each other to continue the effect of temperature and thus ensure better curing of the adhesive. This practice is mainly implemented in case of bonding with alkali-curing phenolic adhesives.
Treatment in which the wood is immersed in the preservative, heated and then, after an appropriate period, allowed to cool. The wood preservative is absorbed by the timber when cooled.
Adhesive that softens on heating and hardens when cooled. It therefore retains the ability to melt and remain soluble. It is applied in the molten state and forms a bond by cooling and consequently returning to a solid state.
Insect of the Cerambycidae family. Commonly known as the “house longhorn beetle”, it is found up to an altitude of about 2,000 m, although of minor importance in northwestern Europe. Its viability and longevity depend mainly on ambient temperature and wood moisture. It attacks numerous Conifer species. Where present it can cause severe structural damage.
Joint that consists of a piece notched or grooved in such a way to receive another piece.
Harmonised System (HS Codes) also known as Commodity Codes (CC Codes), is an international nomenclature for the classification of products.
Conditions corresponding to service class 2 of EN 1995-1-1:2004, whereby the moisture content in the material corresponds to a temperature of 20°C and a relative humidity of the surrounding air over 85% for only a few weeks per year.
A series of ring swellings that are perpendicular to the trunk axis, caused by the presence of undulating fibres in the direction normal to the growth rings.
An individual generated by crossing different species, breeds or varieties. In the timber sector, hybrids of poplar are well known and have been used to generate various clones.
Removal of bark from round timber by means of pressurised water jets on the pieces, which are mechanically rotated in closed chambers.
Machinery used for loading wood or timber, consisting of an articulated, hydraulically knuckle-boom loader that ends with a grapple. It may be equipped with a winch.
Lifting device, hydraulically operated, of implements and operating machines placed on tractors. It is connected to the three-point hitch and together they form the load-bearing coupling system.
Measurement of timber volume through the change in its weight once fully immersed in water.
An instrument for determining the relative humidity of the air or for esthimating the moisture content of the wood.
Property of a material to easily absorb moisture from the environment in which it is placed. Wood is a hygroscopic material.
Filamentous element consisting of cells placed one after the other. A set of hyphae constitutes the mycelium.
A wooden structural element whose cross-section is shaped like the letter ‘I’. A similar, but smaller, element is called an ‘I’-shaped joist. This arrangement increases the bending resistance and rigidity of the element due to the positioning of the material at the points of maximum stress.
A cell markedly different in shape and content from others constituting the same tissue. Note: Examples in wood are certain crystalliferous, oleiferous, and mucilaginous cells.
Harvesting in violation of the applicable legislation in the country of harvest.
Wood species Scientific name: Pycnanthus angolensis (Welw.) Warb. ATIBT nomenclature: Ilomba. Origin: West and East Africa
Treatment during which the wood is completely immersed in a preservative solution.
Any defect or imperfection due to imperfect processing of the timber, such as irregular dimensions, irregular planing, etc.,
This includes any owner or other person currently in possession of or beneficially interested in the tree pest or relevant material at any time between its landing from a third country and the time it is discharged by an inspector.
Wood whose cells have been impregnated with synthetic resins in order to materially reduce shrinkage and swelling. In the process, the wood is not compressed.
A material impregnated or coated on the surface with a layer of resin or adhesive mixture used mostly for protection.
A chemical substance that is used to impregnate wood.
Strictly speaking, the saturation of wood with preservative substances; in practice, the introduction of such substances into the wood.
Process through which an impregnating liquid is injected into semi-finished wood products.
Identation caused by the presence of a foreign body on an external ply of plywood.
Generic term used to refer to wood that has undergone a specific treatment to reduce its hygroscopicity, tendency to adsorb, or improve its performance characteristics or surface appearance. Treatments include exposure to high temperature, impregnation with resins or esterifying agents, and densification. Some specific terms include: – Compreg: wood impregnated with synthetic resins such as phenol-formaldehyde and then densified under pressure at high temperature; – Flapreg: a kind of improved flakeboard similar to Compreg; – Impreg: wood treated in the same way as Compreg but not densified; – Staypack: wood densified under pressure at high temperature but not impregnated with resin.
In hills and mountains, it indicates the direction according to the lines of maximum slope.
Load test of the structure or a part of it in order to assess its mechanical properties or to predict its load-bearing capacity.
Application of wood preservatives on timber which is already in service.
Timber infestation in which no live insect is present.
Wood species Scientific name: Libocedrus decurrens Torr. Origin: Western mountainous regions of the United States, from Oregon to California.
English unit of measurement of length.
Early stage of wood degradation which determines not perceptible softening in the hardness of the wood and usually some slight discolouration. Strength properties are not affected at this stage.
Drilling procedure of the surface sides of the wood to ensure deeper and more uniform penetration of the wood preservative.
Sloping (or oblique) cutting with respect to a vertical or horizontal plane of the workpiece.
Formation of a stack (mostly of boards) in slightly sloping layers to allow rainwater to run off. The entire pile results in a slight slope.
Cordons or phloem layers included in the secondary xylem of certain dicotyledons. Two types can be distinguished: -concentric: the short-lived cambium is replaced by new meristematic tissue which develops either in the pericycle or primary bark and repeats the structure of the young stem; the stem thus consists of alternating zones of xylem and phloem (Avicennia type); -foraminate: a permanent single cambium continues to operate throughout the life of the stem and the wood is normal except for the presence of cribrous cords immersed in it (Strychnos type).
Presence in the heartwood of a ring, complete or incomplete, having color and properties typical of sapwood. No living cells are no longer found there (as in normal sapwood), but reserve materials may remain in it.
See “included sapwood”.
In a plywood panel, this term indicates the presence of foreign particles on the plies.
Acronym for “International Commercial Terms.” Standard commercial definitions regarding delivery methods in international sales.
Increase in circumference, diameter, basal area, height, volume, quality or value of an individual tree.
An instrument used to extract a thin radial cylinder (called a ‘core’) from the trunk to determine the age and growth increments of the plant. It is also used to determine the depth of penetration of preservatives into the wood.
Narrow groove in the transverse (horizontal) wall of a ray cell, along the junction with the tangential (terminal) wall. In radial section, a indenture appears as a depression in the transverse wall at the insertion of the tangential wall. Note: it is used only for conifers.
Set of mosaic laths arranged either end-to-end or edge-to-edge.
In the FAO statistics: all round timber with the exclusion of fuelwood, distinguishing between roundwood for work, i.e. suitable for sawing, slicing and peeling, and roundwood for industry, which generally includes small timbers, i.e., properly speaking, pulp timbers, panels, etc., as well as, improperly speaking, pit props and agricultural poles.
Attack and invasion by fungi, microscopic organisms, or viruses.
Massive attack generally related to the biological activity of a degradation agent such as insects.
Settlement within the wood of insects or any organism of animal origin.
In pressure processes, amount of impregnant absorbed by the wood during the filling phase of the autoclave before pressure is applied.
Moisture of wood at the beginning of the drying process.
See “initial moisture content”.
Apotracheal parenchyma cells either isolated or forming a more or less continuous layer of varying thickness at the beginning of the growing season.
Size and moisture content of timber at the start of seasoning or conditioning operations.
Time between the first and second setting of the instrument or reference sample.
Vacuum applied in the first stage of some pressure processes to remove air contained in wood tissue.
Decrease, more or less serious and evident, in efficiency or consistency or value, whether due to intentional or unintentional causes.
Craftwork technique consisting of interlocking elements of various materials (marble, pearl, metal foil, different types of wood, etc.) on a surface, usually of wood, in order to obtain ornamental figures. The term also indicates the result of the workmanship.
Plywood layer of which both faces are not externally visible.
Panel made of particle board, wood wool, or fibres aggregated with inorganic material such as Portland cement or gypsum.