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Ulf T. Runesson

Faculty of Natural
Resources Management,
Lakehead University

955 Oliver Road,
Thunder Bay, Ontario,
Canada P7B 5E1

     (807) 343-8784

     (807) 346-7769


Sap The watery fluid that circulates through a tree carrying the chemical food that enables the tree to grow.
Sanding Sealer A preparation coating which seals the wood in preparation for topcoating and which is easy to smooth by sanding.
Sandwich Panel, Structural Panels made of parallel framing members separated by expanded polystyrene which act as structural units in resisting horizontal or vertical loads.
Sandwlch Panel, Non-Structural A panel comprised of a foam core with plywood or OSB bonded to each face designed to enclose but not to be the main load- carrying elements.
Sapwood The wood of pale colour near the outside of the log. Under most conditions sapwood is more susceptible to decay than heartwood.
Seasoning The process of drying lumber either naturally, or in a kiln, to a moisture content appropriate for the conditions and purposes for which it is to be used.
Service Condition, Dry A service condition in which the average equilibrium moisture content over a year is 15 percent or less and does not exceed 19 percent.
Servlce Condition, Wet All service conditions other than dry.
Serviceability Limit States Those states which restrict the intended use and occupancy of the structure including deflection, joint slip, vibration, and permanent deformation as applied in Limit States Design.
Shake A separation along the grain usually occurring between the rings of annual growth.
Shake A western red cedar roofing and sidewall product made by splitting blocks of cedar, as opposed to shingles which are manufactured by sawing.
Shearwall A wall or partition designed to transfer lateral loads (wind and earthquake loads) from abutting walls and roof to the foundation.
Shrinkage The decrease in the dimension of wood resulting from a decrease of moisture content and generally occurring to the greatest extent between about 20 and 30 percent moisture content.
Strength Limit States Those states concerning safety and including the maximum load-carrying capacity of the structural materials of the connection as they relate to Limit States Design.
Slope (Pitch) The ratio of vertical rise to horizontal run for inclined members (generally expressed as 3/12, 4/12, 5/12 etc.).
Slope of grain The angle between the direction of the grain and the axis of a piece of lumber, expressed as a ratio.
Softwoods (conifers) One of the botanical groups of trees that in most cases have needlelike or scalelike leaves.
Solvents Volatile liquids used in paint, stain, varnish, and lacquer coatings which give the coating workability and which, upon evaporation, allow the resin to harden.
Specie A distinct sort or kind of tree having some characteristics or qualities in common that distinguishes it from other groups.
Species Group The combining of species into commercial groups because of their similarity in appearance and physical properties.
Springwood (early wood) The portion of the annual growth ring that is formed during the early part of the season's growth; it is usually less dense, lighter in colour, and weaker mechanically than summerwood.
Stain (natural) A discolouration on or in lumber, other than its natural colour.
Stain (chemical) A solution or suspension of colouring matter in a vehicle designed to penetrate a surface and colour the wood, without hiding surface characteristics and providing some protection.
Stud One of a series of vertical load bearing members used as supporting elements in walls and partitions.
Stud Wall System Combination of studs and sheathing panels or boards on one or both sides designed to bear vertical loads and to provide shearwall action.
Summerwood The portion of the annual growth that is formed after the springwood (early wood) formation has ceased. It is usually more dense and stronger mechanically than springwood (early wood).

Texture The relative size and arrangement of the wood cells.
Thermoplastlc Glues and Resins Glues and resins that are capable of being repeatedly softened by heat and hardened by cooling.
Thermosetting Glues and Resins Glues and resins that are cured with heat but do not soften when subsequently subjected to high temperatures.
Timber A piece of lumber 140mm (5-1/2") or more in smaller dimension.
Timber Connector A metal ring or plate that, by being embedded in adjacent wood faces or in one wood face, acts in shear to transmit loads from one timber to another, or from a timber to a bolt and, in turn, to a steel plate or another connector.
Toughness A quality of wood which permits the material to absorb a relatively large amount of energy, to withstand repeated shocks, and to undergo considerable deformation before breaking.
Truss An assembly of members combined to form a rigid framework. All members are interconnected to form triangles. Light frame trusses are made from dimension lumber restrained by toothed plates. Heavy trusses are made for large members restrained by bolts and connectors or glulam rivets.
Truss Plate A light steel plate fastening, intended for use in structural lumber assemblies, that may have integral teeth of various shapes and configurations.
Twist Warping in which one corner of a piece twists out of the plane of the other three.

Varnish A paint coating which lacks pigment and which gives a transparent or translucent finish to wood.
Veneer, Rotary Cut Veneer cut in a lathe which rotates a log, chucked in the centre, against a knife.
Veneer, Sawn Veneer produced by sawing.
Veneer, Sliced Veneer that is sliced from a log with a knife.

Waferboard A mat-formed structural panel board made of wood wafers, randomly arranged and bonded together with a waterproof and boilproof binder.
Wood Preservative Means any suitable substance that is toxic to fungi, insects, borers, and other living wood-destroying organisms.
Wane Bark or lack of wood on the edge or corner of a piece of wood resulting from the piece being sawn from near the outer circumference of a sawlog.
Warp Any deviation from a true or plane surface. Warp includes bow, crook, cup and twist, and any combination of these.
Water-Repellent Preservative A water repellent that contains a preservative, accomplishing the dual purpose of imparting resistance to attack by fungi or insects. It also retards changes in moisture content.
Weathering The mechanical or chemical disintegration and discolouration of the surface of wood caused by exposure to light, the action of dust and sand carried by winds, and the alternate shrinking and swelling of the surface fibres with the continual variation in moisture content, brought by changes in the weather.
Webs Members that join the top and bottom chords to form the triangular patterns that give truss action. They usually carrying tension or compression stresses.
Wood Cells (vessels) The basic units comprising wood having open ends and set one above the other so as to form continu- ous tubes. The openings of the vessels on the surface of a piece of wood are usually referred to as pores.
Wood I-joist, Prefabricated A structural wood member made by using adhesive to attach wood flanges (LVL, MSR, or high quality dimension lumber) to a plywood or OSB web.
Workability The degree of ease and smoothness with which wood can be worked.
Water Repellent A liquid that penetrates wood which retards changes in moisture content and in dimensions without adversely altering the desirable qualities of wood.

Last Modified: January 20, 2014 20:01:06. 
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