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.
Carpentry connection in which two flat timber elements are connected to each other at an angle to the grain by means of a front notch and in which the load is transferred predominantly by compression.
Insects belonging to the Siricidae family.
Insects attacking recently felled Conifer wood. The greatest damage is found on Norway spruce. They are also known by the name “wasp-worm” because of the appearance of the adult, which resembles that of an apis.
Wood species Scientific name: Picea sitchensis Carr. Origin: Western regions of Canada and the United States, from Alaska to California.
An instrument used for the measurement and dimensional control of trunks, logs and semi-finished products.
Four-wheel-drive isodiametric tractor, specialized for tractor-drawn extraction. The body consists of two units connected by a joint: the front unit carries the engine and driver’s seat, the rear unit carries the windlass.
Operational condition in which the load moves together with the towing vehicle (tractor and winch).
Bunching or extraction system by which timber is dragged over the ground. In trailing extraction, the hauling vehicle is stressed by rearing.
In yarders, it is the steel rope suitable for supporting the carriage moving on it.
See “skyline”.
Outer portion of a log, produced during sawing, that has one face sawn off and the other consisting of the outer surface of the log.
Square a log by removing slabs: the result is a slabbed log, i.e. a complete prism.
The totality of the branches and tops of one or more trees, resulting from their limbing.
A flat platform, usually installed on wooden skids, that is normally towed by animals for the extraction or transport of wood or timber. The timber may be fully loaded onto it or only one end of the logs may be supported while the other end slides along the ground.
Sheet of wood obtained by slicing.
A chipless cutting machine used for slicing wood. Depending on the models and cutting patterns, there are: – horizontal slicers; – vertical slicers; – oblique slicers;
Industrial processing that involves reducing an assortment of suitable characteristics into sheets (known as ‘veneers’). It consists of fixing a piece, previously debarked, possibly steamed and suitably squared, to a support base equipped with a translation movement that brings it into contact with a cutting system formed by a knife and a pressure bar at least as long as the piece. Normally the cut starts from the lateral surface of the flitch and continues along planes parallel to the above-mentioned support base. The combined movements of the log and the cutting system make it possible to obtain veneers of limited width (at most equal to the diameter of the original log) and of the desired thickness (generally between 0.5 and 5 mm). After drying and subsequent “veneer clipping” that regularises the longitudinal edges, the sheets necessarily require a lateral jointing operation, aimed at obtaining a width adequate to that of the support to which they will be glued. In order to optimise the decorative characteristics and figures that can be seen on the surface of the sheets, the aforementioned jointing is usually carried out according to specific veneer coupling methods. Like all primary manufacturing, slicing is generally carried out on material with high moisture content (green wood), whose transformation enables lower energy consumption and the production of sheets of better quality and surface regularity. Butt logs of valuable wood species with decorative characteristics are usually selected for slicing.
Juxtaposing sliced veneers by arranging them side by side with the compressed side at the bottom without turning or turning them over.
Bunching or extraction system by which manually moved timber is slid over the ground or along special conduits, taking advantage of the force of gravity.
Translation in the direction of force between two elements of a connection.
Rapporto tra il carico e lo slittamento
See “sliver”.
Particle, also called “splinter,” that has small but constant cross section and length, parallel to the grain, greater than four times the thickness.
Series of triangular teeth arranged at wide intervals on the back of a band saw blade. They are used to remove wood chips during the return stroke of the carriage.
In wood flooring elements, it is the angle formed by any edge or end in relation to the face.
Expression of the angle formed by the grain in relation to the longitudinal edges of the semi-finished product (usually a sawn timber or veneer).
Very thin strip of wood of various lengths and widths produced during planing and shaping operations (not during sawing, which produces sawdust instead).
Round timber with a diameter less than a conventional limit. Sometimes a minimum size is also specified.
Primitive kiln in which timber is exposed to heat and smoke from an open fire.
In peeling, the term refers to the surface of the sheet that is in contact with the back of the knife during cutting and is therefore not affected by peeling cracks. Occasionally, the same definition also applies in slicing, especially if thick veneers are obtained.
A cut with undulations due to deviations from the correct sawing line.
Surface sinuosity caused by defective sawing.
Breaking of the trunk or branches of a tree caused by excessive accumulation of snow.
Potassium or calcium-based material used as a coating material.
Part of cortex that consists of sieve tubes, parenchyma cells, and suberized cells, but has no fibers or other supporting cells. It is present in concentric layers that alternate within a growth ring with layers of hard cortex, or forming a fundamental tissue in which hard cortex cells are irregularly distributed.
Structural fungal alteration, caused by imperfect fungi and ascomycetes, which settle in the middle layer of the secondary wall of wood cells, demolishing cellulose. In the humid state the surface of the attacked wood becomes darker and softer to the touch, while in the dry state it hardens and cracks longitudinally and transversely. The alteration affects wood that is in contact with soil or in water and initially results in a softening of the surface that, as the damage continues, gradually extends to a greater and greater depth. For their development, these fungi require higher wood moisture than that required by basidiomycetes.
Wood species Scientific name: Acer rubrum L. e Acer saccharinum Wangenh. Origin: North America.
Fibreboard with a density below 0.40 g/cm3.
Wood from trees botanically included in the category of Gymnosperms, predominantly represented by needle-leaved and evergreen species (e.g., firs, Douglas firs, pines, cypresses). The English designation “softwood” is not always indicative of the actual hardness characteristics of the material. Softwood is also called “homoxyl” wood, as opposed to the “heteroxyl” wood of deciduous trees, because it is composed mainly of only one type of cell (tracheid), with both mechanical and fluid-conducting functions.
Term currently used to refer to trees and wood of species belonging to the botanical group Gymnospermae, but in practice it is used for conifers only. Note: The widely used English term “softwood” also refers primarily to commercial timber (=coniferous timber).
Semi-controlled drying process that uses, along with forced air circulation, solar radiation as a heat source.
Solid fuel directly or indirectly produced from biomass.
Wood flooring with a solid wood layer at least 2.5 mm thick.
A measure of a quantity of round wood by its size (usually in cubic meters). The German term “Festmeter” (fm) is not recommended.
It represents the ratio of the solid volume of wood in a stack to its stacked volume.
Sawn or processed wood, which may include finger-jointed assembled wood (e.g., solid wood panels) and/or laminated wood.
Panel composed of elements of equal thickness glued together on the edges and, if multilayer, also on the faces. With indication of their intended use, technical classes for non-structural use and technical classes for structural use are distinguished. In particular: Technical classes for nonstructural use: -SWP/1 NS: solid wood panel for non-structural use in dry conditions. -SWP/2 NS: solid wood panel for non-structural use in wet conditions -SWP/3 NS: solid wood panel for non-structural use in outdoor application Technical classes for structural use: -SWP/1 S: solid wood panel for structural use in dry conditions. -SWP/2 S: solid wood panel for structural use in wet conditions -SWP/3 S: solid wood panel for structural use in outdoor application.
Panel intended for use in a protected outdoor environment as specified in Service Class 3 of EN 1995-1-1 and Use Class 3 of EN 335. Note 1: The panel is also capable of withstanding exposure to weather and liquid water or water vapor in a humid but ventilated location, where it can reach a humidity of more than 20%. Note 2: Service Class 3 is characterized by higher material humidity than Service Class 2.
Panel intended for outdoor use with no risk of wetting as specified in EN 1995-1-1 Service Class 1 and EN 335 Use Class 1. Note: Service Class 1 features material moisture corresponding to a temperature of 20° C and a relative humidity of the surrounding air greater than 65% for only a few weeks per year.
Panel intended for use in a protected outdoor environment as specified in Service Class 2 of EN 1995-1-1 and Use Class 1 of EN 335. Note 1: It is also capable of withstanding exposure to weathering for short periods. Note 2: Service Class 2 is characterized by material humidity corresponding to a temperature of 20° C and a relative humidity of the surrounding air above 85% for only a few weeks per year.
Weight percentage of the non-volatile component of an adhesive.
Pore completely surrounded by other elements.
Adhesive dissolved or suspended in a volatile organic liquid, which therefore differs from those in aqueous solution.
A process used to recover part of the solvent absorbed by wood treated with a light solvent organic preservative.
Extraction of water contained in wood and other substances by means of a hot solvent miscible in water (e.g. acetone).
Long platform in a sawmill on which sawn timber is conveyed to be classified into the different qualification and measurement categories.
A change in the intensity and depth of colour of wood that does not lead to a reduction in its mechanical properties. It is caused by chromogenic fungi and occurs mainly in the sapwood of certain woods.
Knot that does not show degradation (i.e. traces of alteration or rot).
Wood free from degradation caused by biological agents.
Capacity (of an artifact that separates two contiguous environments) to attenuate the sound energy that propagates by air (or by impact) from the disturbing environment to the disturbed environment (receiving environment).
Wood species Scientific name: Chamaecyparis thyoides L. B. S. & P. Origin: Atlantic coastal regions of the United States, including those in the Gulf of Mexico.
Section of steel rope (skyline) between two successive line supports.
A log that has a predetermined diameter and/or length based on its intended use.
“Group of plants that have nearly identical characteristics and transfer them to their descendants.” In practice, referring to the species to which it belongs makes it possible to uniquely identify a type of wood.
Group of two or more wood species or populations of the same tree species of different origin combined together for marketing on the basis of similar properties and used interchangeably.
Ratio of the mass of a body, (e.g. a sample of anhydrous wood) to the mass of an equal volume of distilled water at a temperature of 4 °C and under normal atmospheric pressure. According to this definition, it is a dimensionless quantity once also known by the term ‘specific gravity’.
Characteristic property of a substance that expresses how much heat it is necessary to supply a kilogram of the same substance to raise its temperature by 1 °C.
See “specific gravity”.
Document that prescribes the requirements to which the product or service must conform. A specification usually includes or refers to drawings, schemes, or other documents and indicates also the methods and criteria by which compliance with them should be checked.
Small dark stains typical of some wood species.
Excavator whose support base is equipped with four independent support arms, adjustable both horizontally and vertically, two of which are equipped with idle or motorized wheels.
See “spider excavator”.
Knot whose maximum to minimum diameter ratio is greater than 4.
See “spike knot”.
Shaft (usually fixed on a slide) that emerges vertically on the sawbench and on which various tool holders can be mounted according to the way the wood has to be processed. It is used to cut shapes and profiles or to make fluting on elements that have already been planed.
Partial board splitting due to sawing of logs in which, as a result of the anomalous helical orientation of the grain, a similarly spiral V-shaped crack occurred.
A singularity (defect) in wood whereby the main anatomical elements (fibres or tracheids) are arranged in a helical pattern in relation to the growth axis of a stem or the surface of a semi-finished product.
Helicoidal reliefs on the inner face of the secondary wall cell.
Arris knot whose maximum and minimum diameter ratios on the face are greater than 4.
Plywood whose outer layers are formed by several strips joined together, either sideways, or butt-jointed.
Machine to splice two plies in order to form a larger one.
Joining of two ends of a steel rope, or connection of two steel ropes with equal characteristics, obtained by substituting in the winding of the wire ropes of one end the wire ropes of the other end.
Small wood fragment detached from the main body of the woody element.
Crack that occurs on the two opposite sides. Note: The French and German terms are also used for round timber indicating what is known as “traversing crack.”
Separation of the main anatomical elements (fibres or tracheids) that extends along the grain (i.e. in the axial direction) affecting the entire thickness of a semi-finished product (of a single sheet in the case of plywood). It generally originates during the manufacturing process or handling phase.
Assortment of wood species whose fibres are easily separated by cutting parallel to the grain with an axe. This is usually done in the processing of firewood, shingles or barrel cask.
Outer layer composed of 2 veneer layers overlapping and glued together with parallel fibres. The outer layer is glued to each face of the core.
The action of separating wood in a direction parallel to its grain using a sharp tool (usually an axe or wedge).
Treatment in which absorption of the substance occurs without any alteration of environmental conditions (pressure, temperature).
Cell originating from sexual reproduction in fungi.
The application of glue in scattered dots, typical in the gluing of core plywoods.