Types of wood and characteristics of sawn timber

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None of the building materials currently on the market has such unique qualities as natural wood. It is very convenient and easy to process, so that you can do anything, at least a spoon, at least fuselage of an airplane. Wood has excellent strength, it is light and has a pleasant smell. Working with wood brings real pleasure, if you understand what kinds of wood and characteristics of lumber are.

Building materials from wood

Building materials from wood

Varieties of sections of wood

If you look at any wood bar, you can see on it a textural pattern formed by year rings. Its appearance depends on the direction in which the tree trunk was sawn. It is decided to cut it in three directions: along and across the fibers, and also at an angle of 45 degrees. If the cut is produced at an angle, then it is called tangent. It forms a texture that looks like a cone-shaped line.

Three different types of slices depending on the direction

Three different types of slices depending on the direction of the

If a cut is made along the fibers, then it is called radial. It can clearly see the parallel lines formed by the fibers. The transverse section in all its glory shows us the annual rings of the trunk of a tree. Drawing is important for the external beauty of wood products, so before you make a wooden workpiece you need to clearly identify yourself in which direction we want to have patterns.

Internal structure of wood

In order to understand the structure of the tree trunk, a full cross-section must be made. The top layer is called the bark. It is of no interest, therefore it is deleted. The next thin layer is the so-called growth zone. It is difficult to see, but if the tree is young, then after removing the bark, you can see the green fibers that are wet to the touch. They are also called cambium. After it, and the wood begins with pronounced annual rings. Professionals call it sapwood. In the center of the trunk is a darker or merging nucleus with the sapwood. It depends on the wood species, which can be sapwood or sound.

Sound tree species are represented by all conifers( cedar, pine, spruce, larch, yew) and some deciduous common species such as oak, poplar, ash. The vast majority of deciduous trees are sapwood: birch, alder, hornbeam, maple.

The density of wood cells affects the strength and other physical qualities of wood, but the drawing of annual rings and heart-shaped vessels affects the creation of artistic compositions and the possibility of using one or another raw material in the work. These are macrostructural elements, and to them can be attributed still knots, outgrowths, undeveloped shoots, deflecting the annual rings and forming a variety of pigs.

Wood with a pronounced macrostructure is the most interesting for processing, therefore, all conifers are used for crafts without exception.

. Physical characteristics of

wood. As with any building material, wood has a number of physical properties:

  • The density is measured in g / cm3 and depends on the wood species and its moisture content. The higher this index, the stronger and heavier the material, it is more durable and less prone to rot. The most dense is the wood of oak, ash, maple and larch, and the lowest density is aspen, spruce and fir.
  • The moisture content of wood indicates the degree of its quality and durability. Room-dry has 8 - 12% moisture, air-dry from 12 to 18%, and atmospheric-dry 18 - 23%.If the humidity is even greater, then such wood is called damp.
  • Sound conductivity and thermal conductivity are important qualities. Quality dry wood perfectly retains heat and sound in the transverse direction. Along the fibers, the thermal conductivity is reduced, but the sound along the trunk is spreading fine. This is even an indicator of quality and dryness.
  • Resistance to corrosion, which is higher in coniferous wood due to the presence of resin in it.
  • Texture, color, smell and gloss make it possible to determine the wood species and determine its decorative value.

All of the above physical properties are very important for the use of a particular tree species.

Mechanical characteristics of wood

Mechanical properties of different types of wood are more important. After all, they affect the strength and durability of buildings or products made of wood. Mechanical strength is the ability to resist to various static and dynamic influences from outside. The strength of a material depends on the direction in which the load acts. In connection with this, it is customary to distinguish between shear strength or shear, bending and compression. Any wood has great strength along the fibers rather than across them.

The strength test of the wooden bar in the direction of the load

Testing the strength of a wooden block in the direction of load

It should be noted that wet wood becomes less durable. The same is observed in light and loose rock.

Plasticity is a property that allows you to create bent parts from a tree. The more ductile rocks retain the shape obtained by a certain prolonged exposure. Humidity and temperature greatly increase this figure, so for the production of curved parts, the wood is exposed to hot water or steam. High buoyancy boasts beech, elm, oak, ash. This can not be said about conifers, since the structure of their fibers is too straightforward.

The hardness of wood is the ability to resist the various insertion of foreign bodies into it. There are solid types of trees, such as: beech, maple, larch, oak, ash, elm( the hardest are boxwood and acacia) and soft, such as: linden, alder, spruce, pine. The level of wear resistance of wood directly depends on its hardness.

Characteristics of different species of wood

For different purposes, this or that type of wood is used. All of them are divided into coniferous and deciduous. The first have a sharp resin smell and a pronounced macrostructure. The most common coniferous species are: cedar, pine, fir, spruce and larch.

  • Pine is the most common building material. Its color varies from pale yellow to reddish-yellow. The wood is light enough and strong. The main thing is that it is very convenient for processing. It contains a lot of resin, so it rotes badly and is not particularly afraid of precipitation. Because of its softness, it easily accepts various colorants and varnishes. Crushing during drying almost at the pine does not occur. The disadvantage is the impossibility of high-quality finishing and coloring. However, it is successfully used for the production of furniture and plywood.
  • Spruce can be put on the second place after the pine by the level of use. Resins in it are not so many, so it is more prone to rot and rainfall. The wood at the spruce is strong and light, but at the same time it has a large number of knots, which considerably reduces its consumer qualities. The advantages include white wood color and low resinity. It holds well the various fasteners. In the construction of it do not the most important details.
  • Cedar, or properly Siberian pine is in no way inferior to spruce for its building qualities, and in its resistance to rot, it far exceeds it. Despite the softness of the cedar wood, it has a good density and strength, and can be processed very well.
  • Fir is nothing special from spruce: it is easily amenable to any processing and does not perceive corrosive chemicals. It is small enough resin, because of which the wood rotates too fast without using a special treatment.
  • Larch is appreciated for its hardness and strength. Its density is such that the trunk of this tree sinks in the water. But larch wood practically does not rot.

Hardwood is usually divided into soft and hard. Their wood is odorless. He is only on a fresh cut. Hardwood species include oak, ash and birch, and to softwood aspen and alder.

  • Oak has a very high strength and resistance to rotting. Its wood has a beautiful color and texture. It does not crack and does not crumple, so oak makes furniture and luxury items and art. Tannins have powerful antiseptic properties. The most durable and beautiful oak wood is obtained when it is held for 1.5 years in running cold water. Its color turns black. From such morainic wood objects of expensive furniture are made. It is an ideal material for furniture production, but it is very inconvenient in processing because of its density and strength
  • Birch wood has an average density and hardness. It is strong and viscous enough, has a not very pronounced texture, but is uniform. The disadvantages of this material are susceptibility to severe cracking and buckling, too much shrinkage, little resistance to decay, quite frequent damage such an ailment as a wormhole. However, it can be handled with a hand tool, glued in plywood, easily polished and color-treated, makes it possible to produce a very small embossed carving.
  • Aspen has a fairly soft wood, in which there are so few knots that it can be easily processed. However, its porous structure does not allow making small details.
  • Lime is very valuable when manufacturing various carved parts for furniture production. It does not warp and does not crack at all when shrinking. Lime wood has a fairly strong structure, which is very slightly susceptible to decay.
  • Maple has a strong, dense and slightly drying wood. It almost does not warp, but quickly rot and is highly susceptible to a wormhole. This wood is well processed, glued, trimmed and painted. It is used in carved work and the manufacture of parts from the array.
  • Mahogany, which grows in evergreen tropical forests, has redwood. It is not a single species, but many with similar properties. The mahogany wood is very soft and perfectly treatable, easy to polish, and also absorbs lacquer. Some pieces of furniture are made from such wood. Its high cost does not make it possible to make the entire product out of it.

Rare wood

Rare wood species

Rare wood

Lumber and varieties

Predominantly in the forestry and in the store they sell dry wood. Raw is rarely sold. If you decide to build something or make a piece of furniture, then you will come across names of types of sawn timber, the meaning of which should be understood:

  • The log is essentially unbroken trunks of trees without bark or their long enough pieces. It is important that their diameter exceeds 25 cm.
  • The garter is the same log, but is less than 25 cm in diameter.
  • A pole is a solid trunk without bark with a diameter of less than 9 cm.
  • The plate is a half ridge that is sawn along the fibers.
  • Quarter - half a plate, sawn along the fibers.
  • A ladder, or in another way a bar with a view, is a log from both sides, which can be laid on one of two planes.
  • I call the beam a log, which is cut from four sides with a cross section of at least 100x100 mm. If it is smaller, then the product is called a bar.
  • The board is very different depending on the method of its processing and dimensions: unedged, edging, croaker, planed on four sides, sheeted, folded.
Cross sections of boards depending on the processing.

Cross sections of boards depending on the processing.

All lumber that is used in construction has its own specific names. They differ in the thickness of the product, as well as the ratio of the width to this thickness. For boards this ratio should never be more than 2. The maximum permissible thickness of the boards is 100 mm. The length of any material from hardwoods does not exceed 5 m, and from coniferous 6.5 m.

The main types of sawn timber

The main types of sawn timber

After reading this article, you got acquainted with the basic concepts and characteristics of wood. Therefore, with this knowledge, you can safely purchase lumber, in terms of terms, not worse than sellers. Today, virtually no major construction or repair can not do without the use of wood to some extent, so this knowledge will be very useful.

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