The hardest wood species: wood properties, application secrets

Recommendation points

• Hornbeam
• Boxwood
• Iron tree

In this article we will tell you about unique hard wood species that are rarely found in nature and even less often found in the form of products. You will learn about the strength and toughness of these rocks and where they are used. The article also contains a comparative description of the properties of wood.

Continuing the theme of exotic wood species, we will tell you about a material that until recently was not available in Russia. The development of trade and transport made it possible to deliver exclusive products and furniture from the timber of the tropics, Africa and Oceania. Over time, these products have gained wide popularity not only as a luxury or exotic item, but also as a practical building material with unique properties..

Hornbeam

The uniqueness of this type of tree lies in the fact that it is popular not so much as lumber, but in living form. He is the only one of the listed, which can be found on the free sale.

Hornbeam grows in the Northern Hemisphere and is most common in China. Its structure resembles a bush, but it grows very slowly. It is thanks to this combination – bushiness and slow growth – that the live hornbeam has become a favorite material for masters of landscape gardening and lovers of green hedges. The green head of the tree holds its shape for up to 15 days after cutting, and the density of the branches allows for the creation of opaque living sculptures. The hornbeam has won great love in Japan, where the art of bonsai is popular – for this purpose, decorative species are specially developed.

The mechanical properties of hornbeam wood are at least impressive:

1. Density – 750 kg / m³.
2. Cross section hardness – 83.5 MPa.
3. Brinell hardness – 3.5 kgf / mm².

These indicators are an order of magnitude higher than that of the average (reference) oak. However, such properties have their price, and it lies in the disadvantages of hornbeam lumber:

1. High volumetric shrinkage. The material shrinks and cracks when dried.
2. Difficult processing. Due to the peculiarities in the structure of the fibers, the hornbeam does not lend itself well to conventional grinding.
3. Dries slowly and is difficult to handle with tools.

The undoubted advantage of such lumber is a beautiful winding structure, sometimes of different colors (dark brown and yellowish). Hornbeam is used to make piece and art products – billiard cues, musical instruments, souvenirs and some machine parts.

Boxwood

This evergreen shrub has other names – green tree, shamshite, buks, bukshpan, gevan. Such an abundance of different names is explained by the antiquity of the breed and the breadth of the growing area – Central Africa (Madagascar), Central America (Cuba, North Mexico), Eurasia.

Like the hornbeam, the boxwood has a lush, dense crown that grows slowly and keeps its shape perfectly. Alive, it is used in landscaping and park architecture..

Since ancient times, boxwood has been used as a medicine in the preparation of decoctions and infusions. Today this is not done because of the high toxicity and toxicity of all parts of the plant. Leaves are especially poisonous.

Mechanical properties of wood:

1. Density from 830 kg / m³ (dried) up to 1300 kg / m³ (freshly cut).
2. Cross section hardness – 115.5 MPa.
3. Brinell hardness – 3.9 kg / mm².

The boxwood trunk does not have a kernel, so lumber is widely used in artistic cutting, decorative sculpture and woodcutting. The felling of this tree is strictly controlled around the world, because due to its exceptional properties, it was so widely used in printing in the early 19th century that it was almost completely destroyed. The high cost of wood makes it unprofitable and irrelevant to manufacture joinery from it.

WIKIPEDIA:The area of ​​boxwood in Russia is constantly decreasing due to felling. Especially large areas of relict boxwood forests were damaged in autumn 2009 during the construction of the Olympic road Adler – Krasnaya Polyana. Several thousand trunks were uprooted and buried. Colchis boxwood is listed in the Red Book of the Russian Federation.

Iron tree

Several dozen tree species are united under this name, which grow mainly in Asian countries, Oceania and Australia. They are distinguished from all other trees by one feature – a density of more than 1000 kg / m, i.e., more than the density of water.

Parrotia persian(iron ore, demir-agach, ambur) – named after the naturalist Ivan Parrot. It grows in the relict forests of Azerbaijan. Its beautiful appearance and frost resistance made it a popular ornamental plant in Europe. Due to its rarity, the wood has not been classified, but it is known for certain about its exceptional strength. Locals have long made axes, floorboards and responsible carpentry from it. The cost of parrotia is several times higher than for wood with the same properties – relict forests are protected by the state and UNESCO.

Quebracho or mahogany– grows in the northern regions of Brazil and Argentina. Its name comes from the combination of the words quiebra-hacha (Spanish), which means “to break the ax”. Red quebracho is relatively common in Russia, so there is evidence of its tests:

1. Density – 1200 kg / m³.
2. Cross section hardness – 81.5 MPa.
3. Brinell hardness – 3.2kg / mm².

In addition to the “eternal” material for furniture, tannin is of great value in quebracho wood, which gives it a red hue. An extract is obtained from bark and wood, which is used to treat asthma, heart and circulatory diseases.

A less common type – white quebracho – has a lower density (850 kg / m³) and is rarely used in Eurasia due to the availability of cheaper local analogues.

Backout or Guaiac tree– the national symbol of Jamaica (flower). It grows on the islands of the Caribbean, South America and India. Its wood is so dense that it does not have the ability to split, and ranges from 1200 to 1450 kg / m³. Bakout resin is valuable for medicine – it is used to make medicines and chemical reagents.

The exceptional hardness and high natural oil content give the wood durability and good mechanical properties. The “track record” of the backout is the most impressive of all:

1. Details of the oldest sailing ships that have survived to this day.
2. Details of a grandfather clock with a wooden movement.
3. Bearings (!) In steering and screw mechanisms of diesel submarines and turbines of the power plant (!) Conowingo on the Susquehanna River.
4. Bowling balls, croquet sticks and batons for British police.

The list of applications makes it clear that in some cases, the backout may well replace iron..

Acquiring materials from the trees described above is extremely difficult for two reasons. First, most of them grow in the tropics or remote (from Russia) regions of the world. Second, almost all of them are under protection because of their rarity. Therefore, the acquisition of this valuable material is a separately taken task that should be planned in the long term..

However, there is a more popular and acceptable solution – the use of an imitation of a given breed from a more common and cheaper material. For example, a larch parquet board can be finished with a thin layer of querbacho and look like querbacho after installation. This approach brings the desired result, wisely saving money and natural resources..