In this article we will talk about how to choose the right wood species, how deciduous and coniferous species differ and are similar, and how to distinguish them. In the article you will find information on the physical and mechanical properties of wood of different species, as well as their market value.
Furniture made of wood of African or Madagascar origin can now be found far beyond the Arctic Circle, thanks to the development of transport and communications. In this article we will try to understand the selection of wood for different needs..
At the mention of lumber and wood in construction needs, only conifers come to mind – spruce and pine, less often larch. When erecting temporary and permanent frames, truss systems, scaffolding and scaffolding, floors, indeed, coniferous sawn timber is mainly used. This happens for several reasons:
- Widespread prevalence. Conifers grow from the equator to the northern regions.
- Abundance of forests. This allows you to harvest wood widely.
- Relatively fast growth of new trees.
- Affordable price.
Together with these advantages, softwood lumber has a relatively low strength and density, a standard texture and is less susceptible to insect attacks and rotting. Flexural strength – 74-79 MPa.
How to distinguish spruce from pine (board):
- Spruce. Has an almost white color, small “dead” knots are often located – every 20-30 cm. Fine grain of wood fibers and low resin content. The fibers have “pockets” with resin, which flows out when the temperature drops (heating). Spruce is often eaten by the bark beetle even before the workpiece (characteristic holes remain).
- Pine. The color is closer to yellow-brown, a large array of fibers, “live” knots every 60–100 cm. Pine is somewhat heavier than spruce due to saturation with resin.
Among the coniferous wood material, it is worth highlighting larch, which withstands 97 MPa for bending and has an unusual property – it turns to stone in water. Therefore, the pillars of the “floating cities” of Venice and St. Petersburg are made from it. In appearance, it resembles a spruce, but 2-2.5 times heavier.
Breed Flexural strength, MPa Compressive strength, MPa Density, kg / m3 Price 1 m3, rub. Fir 51.9 33,7 550 6,700 Spruce 74.4 42.3 480 7,500 Pine 79.3 43.9 450 9,500 Larch 97.3 51.1 650 12,500
Less common trees with properties that are an order of magnitude higher than conifers. These include birch, maple, ash, oak and others..
Birch has a higher flexural strength (99 MPa) than pine, but it is lighter and less susceptible to damage. The birch block is widely used for the manufacture of tool handles and upholstered furniture frames. Color – light, almost white.
Oak wood is not only more dense (800 kg / m3), but also much harder than the others (54 MPa). This allows it to be used in industry for temporary linings, frames and timber structures in workshops. Another area of application of oak is exclusive furniture, interiors, decor and musical instruments. Exceptional durability and interesting texture of oak ensure great demand for this type of wood.
Usually the color of oak wood is from brown to dark brown. The rarity and high cost of this material is due to the fact that oak grows much longer than pine, and, accordingly, the forest resource is renewed longer.
Breed Flexural strength, MPa Compressive strength, MPa Density, kg / m3 Price 1 m3, rub. Oak 93.5 52.0 800 33,000 – 45,000 Birch 99.7 44.7 580 9,500 – 12,500 Ash 115 51.0 750 27,000 – 34,000 Maple 109.7 54.0 670 28,000 – 35,000 Elm 85.2 38.9 660 23,000
This category includes alder, aspen and linden. Due to the flexibility of the material for manual processing, they are mainly used for wood carving and the creation of art panels. They were not widely used in construction due to their low distribution and weak technical properties. Linden can often be found in filling sections of wooden fences, clapboard decoration and the installation of baths and saunas. Alder shavings are used when smoking products.
Question.Why does wood have a dark or light shade?
Answer.Darkening of wood fibers is a sign that oxidative processes have taken place in them. If they occur during the life of a tree, tannins are released in a chemical reaction, which give such strength to dark species..
Valuable wood species
This category is exotic varieties, the high price of which is due either to transport costs or due to the rarity of the breed. In the overwhelming majority of cases, they are chosen because of the appearance of the cut wood, natural color and texture. They also often have unique properties – lightness combined with flexural strength or high density combined with durability..
The density of this tree is 120-200 kg / m3. For comparison, the density of the foam is 35 kg / m3, while the tree remains a tree – it is subject to processing, splicing, bending. Ancient ancestors made canoes out of it. Thor Heyerdahl’s Kon-Tiki raft was made of balsa.
Balsa wood is soft, so products from it are mainly used for decorative purposes – panels, details of luxury furniture, souvenirs and art products. However, balsa has another, “hidden” life. This wood of exceptional lightness is used in lifejackets, floats and buoys, aircraft construction, for the production of coarse fabrics or mattress padding (fibers). Surfboards or balsa table tennis rackets are common..
This tree grows in the equatorial part of South America. It is extremely difficult to acquire it in Russia. Cost 1 m3 in Russia – from 180 thousand rubles.
This tree is called “African oak”. Density 800 kg / m3 and hardness 550 kgf / cm2 made it the benchmark for comparison with other timber species in the Philippines. This tree is of great importance for the place of growth in the culture of the people of Papua New Guinea. Some tribes do not have a written language, and merbau products are passed from generation to generation as part of the cultural heritage. African oak was used for the frame, keel and mast of the ship, sleepers and temple supports.
Merbau wood is extremely resistant to abrasion, therefore it is used in floor coverings without additional processing (staining, varnishing). It is also used to produce doors, parquet, fittings, decorative details, and a board for outdoor terraces. Merbau is a sign of luxury even in the smallest details: billiard cues, walking sticks, armrests, hunting weapon handles, interior trim for luxury cars and airplanes..
Unfortunately, the forests where the merbau tree grows are destroyed innumerable for the purpose of profit. The cost of a cubic meter of valuable timber at the cutting site is $ 11, in the USA 26 m2 finished parquet (1 m3) costs $ 2300. The 200 times price difference pushes people to illegal logging and export. 80% of commercially available merbau forest is illegally mined and exported.
The cost of parquet from merbau in Russia – from 6500 rubles / m3, terrace board (55 m2) – about 360 thousand rubles.
In the following articles, we will talk about other (unique) wood species and how they are used in practice..