Softwood is typically used in construction as structural carcassing timber, as well as finishing timber. The density of the wood, a key factor for many technical properties of wood, is determined largely by the proportion of summerwood in the width of the growth ring. 90–95 percent of the wood is made up of long, hollow cells, which the forest industry calls fibres. Box 55525, The outer bark encases the whole stem, providing protection from water loss and various parasites. Softwoods on the other hand come from trees that are known as gymnosperms. For example, wood is considerably stronger in the direction of the fibres, i.e. This guide presents details of the botanical classification, properties and uses of the most commercially important American softwood species. The growth rings therefore tend to be narrower and have thinner bands of summerwood in colder climates than in warm ones. Properties: Pine is a soft, white or pale yellow wood which is light weight, straight grained and lacks figure. Softwood is wood from gymnosperm trees such as conifers. The properties of softwood ? following the length of the stem, than at right angles, across the grain. Pines and spruces have a similar composition. Bleached tells, it has high brightness and Kraft tells that Kraft (Sulfate) pulping process is used to produced this pulp. It’s additionally … They belong to the botanical group Gymnopermae plants that bear exposed seeds. This layer transports nutrients (carbohydrates) down through the stem and distributes them to the living cells in the tree’s branches, stem and roots. Burning wood only generates moderate amounts of smoke. The woods of longleaf pine, Douglas fir, and yew are much harder in the mechanical sense than several hardwoods. Flexible, lighter in weight and less dense than most hardwoods, softwoods are frequently used for interior mouldings, the manufacturing of windows, construction framing and generating sheet goods such as … Tensile strength is high with the grain, but much lower, around 1/30, across the grain. the hard cones of a pine tree, but are subsequently distributed by the wind over a broad area. Density is a piece of wood’s mass divided by its volume, expressed in kilos per cubic metre. Softwoods are timbers without vessels. A dry piece of wood is stronger than one with more moisture, and colder wood is stronger than warmer wood. Outside the wood lies the cambium, which is the stem’s growth layer. Most species of pine are softer than hardwoods, have prominent annular rings and are lighter in colour than most hardwoods. During the growth season, new cells are formed in the cambium. The density is therefore low in the wood near the pith, compared with the mature wood further out along the radius of the stem. properties, and the manufacturing and grading processes for sawn lumber and glulam. 12%. In planed wood, spruce often has small pick-ups around the knots. Western Red Cedar especially is superior to steel, concrete, and brick in this respect. Hardwood and Softwood Species - Species of hardwood and softwood; Modulus of Rigidity - Shear Modulus (Modulus of Rigidity) is the elasticity coefficient for shearing or torsion force; Softwood Lumber - Grading - Rough lumber, surfaced lumber (dressed), … The cambium is encased with the bast (phloem), which is often referred to as the inner bark. In terms of price, they are often less expensive than hardwood. Visiting address: End-grain flooring is hard and durable as the surface is entirely end-grain wood. Normal variations for the properties of density, strength and stiffness (modulus of elasticity) within the same wood type with an undistorted fibre structure: The quotient is therefore greater between, for example, the average material strength of wood and allowable working stress, in comparison with other construction materials. Softwood is wood from gymnosperm trees such as pines and spruces. The lowest thermal radiation for the ignition of wood with a naked flame is around 12 kW per cubic metre. In the inner part of the stem, in the juvenile wood near the pith, the growth rings are often broad with thin summerwood bands. A gradual fracture is preceded by some form of warning, such as major distortions or cracking sounds in the wood. Fir Softwood. The conifer tree’s wood comprises 40–45 percent cellulose, around 20–22 percent hemicellulose and just under 30 percent lignin. The way the growth rings develop is determined in part by the climate during the growth season. There are also 2–6 percent extractive substances in the wood. The strength of the wood depends on how the stress occurs, there is thus the following correlation: The wood’s strength cannot be fully used up around the fracture limit, so lower levels of stress have to be chosen. The redwood, which is used side grain, provides ideal properties for the border. The width of growth rings and the proportion of summerwood varies within the stem. Softwood properties: On the other hand, softwoods derive from conifers and are more readily available, easily manipulated and develop at a quicker pace, leading to lower cost levels. In the centre of the stem’s cross-section sits the pith, which runs through the whole tree and terminates at the top with a bud. Softwoods are a versatile timber. The sapwood’s moisture content varies between 120 and 160 percent. Hardwoods such as oak and beech are used in flooring and furniture. The summer wood cells, which form during the summer months, are 20–25 percent longer and have much thicker cell walls than the springwood. Examples of softwood trees are: Pine, Fir, Hemlock, Spruce, Tamarack, Cedar, and Redwood. Pine tends to have oval knots. Wood from southern Sweden is denser, stronger and more durable than wood from northern Sweden. Also known as Douglas fir, this wood is often employed in buildings. The properties of softwood ? North American Hardwoods Wood chars slowly and below the charred surface is normal wood, which retains its original properties. Summerwood, which weighs 900 kilos per cubic metre dry wood, is three times denser than springwood, which weighs 300 kilos per cubic metre dry wood. The effective calorific value of pine and spruce as a fuel is 19.3 MJ per kg dry substance. Swedish Wood represents the Swedish sawmill industry and is part of the Swedish Forest Industries Federation. Hardwoods have vessel elements that transport water throughout the wood; under a microscope, these elements appear as pores. Larger dimensions and protection of the wood’s surface can make a wooden structure’s fire resistance higher. Judging the density based solely on the width of the growth ring is therefore misleading. The strength is also affected by the moisture in the wood, its temperature and the period under which it is stressed. They belong to the botanical group Gymnopermae plants that bear exposed seeds. In terms of strength, pine and spruce are treated the same, and they are normally judged to have the same strength values: Stiffness and hardness may also be included in the strength properties. SE-102 04 Stockholm Since wood is used for a whole host of purposes in construction – structural frames, exterior and interior wall cladding, fittings, floor coverings, formwork and scaffolding, the list goes on – it is important to understand how wood behaves under different conditions. Softwood trees are found in temperate and mountainous regions. As such, it is possible to see indicators of good and poor growth years, and how the conditions for growth have been affected by different silviculture measures. Generally speaking gradual fractures, which account for most fractures in wood, are preferable. The growth rings are narrower, with broader summerwood bands, in the outer parts of the stem, particularly in the lower logs. When a length of wood with high stiffness is bent, it doesn’t give very much, remaining quite straight instead. Softwoods are usually found making up the framework of most houses, though they are also useful in creating cabinetry and trim or other decorative finishing touches. In both groups, there is a major change in the actual hardness of the wood, the hardwood density from the solid wood density which is fully included. This is the case whether the load is caused by compression, tension or bending stresses in the wood. In spite of the differences between pine and spruce, they should be considered statistically equal in construction terms. They are both used for a range of structural and decorative projects. A wood with a high density should thus be chosen for flooring. The chart of “Physical Properties of Wood” is divided into three parts -- North American Hardwoods, North American Softwoods, and World Woods, or woods from other places than North America. To see the properties for any wood species, click on its name. Storgatan 19 Wood retains its load-bearing capacity in a fire, in contrast to unprotected steel. This means that the basic density is low, at around 300 kilos per cubic metre. Here you can easily find descriptions of many termes related to wood and wood industry. These timbers mainly have one type of cell that has a dual function, transporting the sap (nutrients) to the leaves and supporting the tree. This is due to the way the wood’s properties spread so widely, which means that safety margins have to be built in. The thicker cell walls mean that the summerwood cells are around three times heavier than the springwood cells, with a basic density of around 900 kg/m3. You can also find links to relevant pages in Choosing Wood. Cellulose Content of Softwood. Compression strength is high in the fibre direction, with the grain, but much lower, around 1/6, across the grain. Softwood trees tend to have less acetic acid (1-2%) than hardwoods (3-5%) (Hatchfield 2002). Additional information on wood properties and characteristics is given in references listed at the end of this chapter. The degree of bending depends on the grain of the wood and on its modulus of elasticity. The thermal capacity of wood is relatively high at around 1,300 J per kg °C for absolutely dry wood. Spruce often has small pin knots between the branch whorls, which pine doesn’t have. What are Softwoods? Function: Softwood fibers (tracheids) confer high tearing strength, ability to withstand multiple folding, and a range of other strength-related properties. Spruce is the wood used primarily as construction timber. The terms “hardwoods” and “softwoods” are not always descriptive Of all available softwood species, cedar tends to be one of the best thermal insulators. Pros of Softwood: Workability: Softwood is easier to work with and can be used across a broad range of applications. They come from coniferous (conifer) trees and have cone or needle shaped leaves. The figures with no brackets state properties parallel to the fibres (II) and the figures in brackets state properties perpendicular to the fibres (T). “The ‘fura’ is the mature tree, where the diameter of the heartwood is more than half the diameter of the stem.”. Cedar trees fall under the Cedrus genus and the Pinaceae family, which is the family of treesthat is coniferous. Material properties vary between the different wood species. Lignocellulosic Properties of Softwood. Phone: Since wood is used for a whole host of purposes in construction – structural frames, exterior and interior wall cladding, fittings, floor coverings, formwork and scaffolding, the list goes on – it is important to understand how wood behaves under different conditions. info@swedishwood.com, The timber industry’s campaign to promote the use of wood in design and construction, UK Timber Industry online information and inspiration, Your calculator for span tables, quantities, volumes, surface areas and angles, One of Sweden’s biggest and most important architectural competitions, The organisation for Swedish pulp, paper and woodworking industries, Wood is a sustainable construction material, Working environment and living environment, Factory-painted and quality-assured external cladding, Moroccan designers explore the potential of Swedish pine. The density is therefore higher in a butt log than in a middle log or top log. Due to them being non-porous they rely … A detailed compilation of the polysaccharide and ligneous composition of wood was carried out by (Fengel and Grosser, 1975). Bending strength is usually measured with the grain. When viewed under a microscope, softwoods have no vi… The reason for this is that the summerwood band, the dark part of the growth ring, is wider in southern Sweden. A summary of basic pulp properties of softwood pulp during ECF bleaching is listed in Table 1. Swedish Wood also lobbies on behalf of its members on key industry and trade issues. The bast is connected to the pith via medullary rays, which are living in the sapwood but dead in the heartwood. The time until ignition can vary greatly and depends on thermal radiation, ventilation and the presence of a naked flame. Wood is the construction material with the oldest heritage in Sweden. I use redwood for borders around cutting boards. The load-bearing capacity of wooden structures in a fire can be worked out mathematically, in line Eurocode 5 for example. They come from coniferous (conifer) trees and have cone or needle shaped leaves. The cells in the heartwood are dead and some have been clogged up with resin, which means that they can’t carry water and thus have a relatively low moisture content, 30–50 percent. Sustainability: Softwood trees grow much faster than hardwood, and are considered a very renewable source. The heartwood and sapwood of spruce has the same colour in the dried wood, making heartwood hard to identify. Despite their classification, softwood is still fairly hard and dense and is used mostly for construction purposes. They also have lignin, but of a slightly different type, and less of it than most hardwoods. Many believe that hardwood is a harder and denser material than softwood, but this is not necessarily the case. Due to the differences in density, the springwood appears as a lighter ring than the dark summerwood. Basic density is defined as the mass of the dry wood sample divided by the volume of the fully hydrated wood sample. In softwoods, medullary rays and tracheidstransport water and produce sap. Drill Bit Speed - Hardwood and Softwood - Hardwood and softwood drill speed chart Fire Wood - the Cord - The cord is the most common unit for purchasing fuel wood Metal Alloys - Specific Heats - Specific heat of metal alloys like brass, bronze and more They come from coniferous (conifer) trees and have cone or needle shaped leaves. Pine is easier to plane without getting such pick-ups. The proportion of summerwood is thus higher, which gives the mature wood a higher density and strength. A high modulus of elasticity means high stiffness. ”Swedish Wood’s aim is to increase the size and value of the market for Swedish wood and wood products in construction, interior design and packaging. The other cells are shorter, with thinner walls. Most of softwoods are used for general construction, fences, and paper pulp. Spruce usually has pitch pockets, which pine rarely has. Because of their versatility, most species can be used for a wide range of applications. balsa) are softer than most softwoods, while the hardest hardwoods are much harder than any softwood. Their cell structure is less porous than Hardwood. Knots and other fibre distortions (imperfections) also affect the wood’s technical properties. The density varies from wood to wood, within the same type of wood and in different parts of the same tree. This is despite the fact that southern Swedish wood generally has broader growth rings than wood from northern Sweden. Through inspiration, information and education, we promote wood as a competitive, renewable, versatile and natural material. Cedar is a type of coniferous wood, meaning that it is classified as a softwood and its cones/needles remain all year round. For wood this is usually stated as the basic density or for a particular moisture content, e.g. All the values relate to wood with 12% moisture content. It is attractive, easily worked, and sufficiently strong. Pine is commonly used for joinery, mouldings and internal cladding, although spruce may be used. Most soft wood have a tall pointed profile and are evergreen. In some parts of Europe, the tree ring chronologies go back over 7,000 years and in the USA they reach 8,000 years into the past. Dendrochronology is a method of determining the age of a tree. +46 8 762 72 60 There are differences between the physical structures of hardwoods and softwoods. [1] In both groups there is an enormous variation in actual wood hardness, the range of density in hardwoods completely including that of softwoods. Softwood samples stored at 50 °C had higher levels of heat release compared to samples stored at 20 °C or 60 °C. The fibre direction deviates from the direction of the forces at knots and when the fibres are not parallel with the edge of the wood. The cambium produces wood cells inwardly and bark (cork) cells outwardly. • Softwoods have needles instead of leaves. The values for strength and modulus of elasticity are average values, and refer to small test samples, with no imperfections, at an average temperature of 20°C. https://www.dummies.com/crafts/types-of-wood-for-woodworking Softwood properties: • Softwoods come from coniferous trees. They belong to the botanical group Gymnopermae plants that bear exposed seeds. Softwood is typically used in construction as structural carcassing timber, as well as finishing timber. The charring rate is around 0.5–1 mm per minute. The properties of softwood ? These fibres are about the thickness of a hair and vary in length between 0.5 and 6 mm. With pine there is a clear difference between the darker heartwood and the sapwood. For example, Balsa Wood is considered a hardwood but is one of the least dense woods and one of the lightest. Hardness refers to the ease with which a surface is damaged by external pressure, for example heels on a floor or knocks on a table top. For the plant propagation technique known as softwood cutting, see, Learn how and when to remove this template message, United States – Canada softwood lumber dispute, "A basic guide to softwoods and hardwoods", Forest Products Annual Market Review 2007-2008, International Federation of Building and Wood Workers, https://en.wikipedia.org/w/index.php?title=Softwood&oldid=993695566, Wikipedia pages semi-protected against vandalism, Articles needing additional references from October 2019, All articles needing additional references, Creative Commons Attribution-ShareAlike License, This page was last edited on 12 December 2020, at 00:22. It is important that softwood is not softer than hardwood. 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