The hardest trees in the world. Hardwoods: what are they? Types of wood depending on density
The people and history called him the Tsar Liberator. Why? On March 5, 1861, the Tsar's manifesto on the abolition of serfdom in Russia was issued.
The abolition of serfdom in our country was perhaps the loudest and largest event in the entire 19th century. From the moment the manifesto was announced, serfs received personal and civil rights.
Now serfs became full members of society. Former captives could freely marry, acquire property, and make various transactions. They could act in court, engage in trade and entrepreneurship, and also enter public service.
Members of peasant communities created rural societies, internal issues were resolved in it general meeting. Several peasant communities together formed a volost, the power in which belonged to the volost assembly.
At such gatherings, elders and volost elders were elected, as well as village elders, and members of the volost board and volost court were elected.
The main issue is the liberation of the peasantry from serfdom - Land. it was necessary to allocate land, but how? The following solution to this important issue was proposed.
Peasants and landowners entered into a voluntary agreement among themselves, called the Charter. According to this charter, the peasants ceased to be temporarily obliged and were transferred to redemption. However, for about two more years, most of peasants still served with the landowners.
Peasants had to pay a ransom for the land. Many believe that the established ransom amount exceeded the market value of the Earth by one and a half times. The state paid the landowner 80% of the ransom amount for the serf. The remaining 20% was paid by the peasants themselves. For fifty years, peasants paid the state cash, paid for them to the landowner, and even with interest.
It is worth noting some features of the allocation of land to peasants after the abolition of serfdom. The land did not belong to the peasant, but to the peasant community. The peasants were connected to the community by mutual responsibility. All payments were made collectively, with community members helping each other within reason.
All lands were divided into three types: chernozem, non-chernozem, steppe. Depending on the territory and the type of soil on it, the size of the plots was determined. The landowner was obliged to sell the peasant land no less than the nth size, and the peasant could not buy land more than the nth size.
The size of the plots was reflected in the charter and included: arable land, pastures, wastelands and an estate. Disagreements between landowners and peasants were resolved with the help of peace mediators.
The abolition of serfdom in Russia was a real breakthrough for the country. The abolition of serfdom was supposed to ensure the development of large landowner and small peasant farms in the country. The emergence of personal and civil freedoms allowed people to actively participate in the life of society and be the creators of their own destinies. More wide use received hired labor, which contributed to the development of industry in Russia.
Surely, many people know that hard wood is distinguished by such wood species as oak and ash. However, if we talk about the hardest wood, then it is “iron” wood. Moreover, in various countries of the world are considered to be “iron” different types trees, characterized by such hard and durable wood, which is often capable of surpassing iron in these indicators. This means that the wood of such trees is very difficult to process, does not float on water and sinks, and can also be used to make nails and even structural elements for cars. So which representatives of the plant world have the well-deserved title of “the most solid wood»?
This hardest tree is present in the forests of Azerbaijan and Iran. In terms of hardness, it is many times stronger than iron. If you want to walk through thickets of such trees, you will very soon realize that this is impossible due to the lack of flexibility of their trunks. Very often, such trees are used to make hedges, which grow stronger and stronger every year.
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This is the hardest tree among the “iron” ones and is found in forests Northern Ireland and Transcaucasia. The black wood has an unusual structure, is very durable and is resistant to various insect pests. Due to the high density of parrotia wood, it is successfully used for the production of wind musical instruments, machine parts and various artistic crafts. This tree is included in the Red Book.
Tiss
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This representative of the “iron” trees not only has super-strong wood, but also does not rot, which is why it received the name “non-iron tree”. Found in Transcaucasia and Far East. In the past, the wood of the “slender wood” was used to make nails and was also used to build structures located under water or underground.
Amazonian and African "iron" trees
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In Africa you can find a tree belonging to the “iron” tree - it is called azobe. In Brazil, a similar tree grows - the Amazonian “iron” tree, which is distinguished by its excellent strength and hardness of wood.
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This is the hardest tree growing in a protected forest called “Kedrovaya Pad” (Primorsky Territory). The strength exceeds the same parameter of cast iron by 1.5 times. You can even shoot this birch tree with a pistol - the bullet will simply fly off and not damage its trunk. The wood of this tree successfully replaces metal. Lives rare tree approximately four hundred years, which is a very impressive life span, because not a single birch tree is distinguished by such longevity.
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The wood of this tree, which grows up to 8 meters, was previously used to produce parts for watches, buttons, gun cleaning rods, and parts for weaving machines. And spears or arrows, which were made from dogwood wood, did not wear out.
Ulin
![](https://i0.wp.com/topkin.ru/wp-content/uploads/2015/07/ulin-massivnaya-doska.jpg)
This Bornean “iron” wood is extremely difficult to process due to the high hardness of the wood. Its smooth texture and pleasant color make ulin especially attractive in the production of parquet, solid board and furniture. You can cut this tree, but you often have to sharpen your tools. But a product made from ulin will last quite a long time.
White acacia
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This tree has wood that in our country is considered one of the hardest. Attractive texture, rich color, excellent strength, highest hardness, excellent resistance to rotting - these are distinctive features this wood. In addition, it is very easy to polish. Acacia wood is used for the production of furniture and parquet.
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It is also called “Brazilian cherry”, but has nothing to do with the “cherry” genus. The tree with high hardness has a wide crown and grows up to forty meters in length.
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The wood of this tree, which grows in Brazil, Venezuela and Colombia, is difficult to work with, but polishes well. Also, sucupira wood is not susceptible to fungi and various pests. Among the trees with durable and hard wood, one can also distinguish ebony, rosewood, and kumara. All these trees sink easily in water and have rot-resistant bark. This means that you won’t be able to make a boat from their wood, but you can make beautiful furniture.
The strength and hardness of timber is determined by several methods. Experts have long compiled a list of all trees by density. Thanks to the results of this check, craftsmen use timber strictly for its intended purpose.
Strength of wood species
The first line of this list is occupied by white acacia, widespread throughout Europe. Brazilian cherry, or jatoba, ranks second in hardness. Products made from this wood have a beautiful structure. Amaranth can be found in Central America. Timber products are characterized by dense and flexible wood. The raw material has a red-violet hue and interesting structure. The strongest amaranth wood is difficult to process, but it is from it that luxury pieces of furniture are produced.
Next on the list is ash, followed by oak. These types of lumber are very heavy and durable. In our country, Schmidt birch is distinguished by the greatest hardness. Bullets fly off it, it sinks to the bottom in a few seconds in water, and is distinguished by its self-preserving property. Products made from it do not rot and are stronger than cast iron.
Durum varieties timber products are used in various areas. For example, Brazilian cherry is an excellent material for creating canes, furniture, and parquet. The durability of acacia parquet is higher than that of oak, and over the years it acquires a more beautiful texture. After steaming, the raw material can be easily bent, which is why it is so popular when creating Viennese chairs.
Iron trees are used to make nails and bearings. These include: Schmidt birch, Amazonian tree, azobe and several others.
Lightweight, durable wood
Balsa tree, which has very light and durable wood, grows in South and Central America. Many people believe that the lightest tree is cork. However, they are very mistaken - it is almost 2 times lighter than balsa. The density of the boards of this tree is 120-160 kg/m3, and the density of cork boards is over 210 kg/m3. Products made from balsa are 9 times lighter than water, and 6 times lighter than oak.
It is worth noting that a freshly cut tree is quite heavy, because the timber contains a lot of fiber cells, which are filled with cell sap. If the wood is not dried immediately after cutting, it will rot within a few days.
These trees are characterized by a colossal growth rate: within six months after seed germination, they reach 3.5 m in height and 25 cm in diameter.
Felling is carried out in 6-10 years. At this time, the tree grows 25-30 meters in height, and the trunk diameter is 1 m (sometimes up to 6 m).
After felling, the timber is dried vertically. During drying, fiber loses moisture and becomes deformed, the cells shrink. Balsa wood is very porous, spongy, but not brittle - 6% of moisture remains in them.
Another advantage of such raw materials is the ease of processing. Craftsmen value it because, despite its low weight, the structures are quite rigid - stiffer than oak or pine. The spongy structure allows this material to be successfully used as a noise and sound insulator. The tree came to Europe relatively recently. Mass exports began during the Second World War, when they replaced balsa wood.
Today they make from balsa:
- wind turbine blades
- sport equipment
- decorations, layouts
- aircraft models
- fiber pillow filling.
Wood tensile strength
It is known that certain qualities of lumber appear under the effect of mechanical work. This:
- strength
- deformability
- technological and operational properties.
The parameters of the mechanical properties of timber are calculated using:
- sprains
- compression
- bending
- shift
Strength - the ability of timber not to collapse under the influence of mechanical work. It is directly proportional to the structure and physical condition raw materials. Strength testing is carried out using standard methods on healthy and small (section 20X20 mm) specimens under static loads using special devices. Based on the results of most processes, maximum strength is recorded, which is the maximum stress that does not destroy the raw material.
Compressive strength is calculated on specimens of a prismatic configuration. The specimen is slowly loaded until there are signs of destruction. After this, the force meter of the testing apparatus is calculated using a special formula. average value the maximum compressive strength along the fibers for all Russian varieties at a raw material moisture content of 12% reaches 50 MPa. And when testing timber for static bending, specimens in the form of a bar are used small size. The average maximum strength reaches 100 MPa.
Mechanical strength of wood
During short-term loads, mainly elastic destruction appears in lumber, disappearing after the load is removed. This indicator is also calculated by specialists using special formulas.
Due to the fact that polymers with elongated chain molecules predominate in the composition of timber, their deformability is directly dependent on the time of loading. The science of rheology studies the mechanical properties of lumber. She learns general patterns destruction of timber under loads, taking into account the time factor.
The strength coefficients of timber under long continuous loads must be studied because they are used in building structures. Experts call maximum long-term resistance a characteristic of this quality. For almost all types of load it is equal to 0.5 - 0.6 levels of maximum strength under short-term static loads.
When drawing up a project for building structures made from timber, craftsmen in their calculations use not the maximum strength of small specimens of timber, but much lower coefficients - calculated resistances.
Specific viscosity is a characteristic of the ability of a raw material to absorb work during an impact without breaking. It is determined during bending tests. This indicator for coniferous timber is two times weaker than for deciduous timber.
Hardness is the limit of resistance of lumber to indentation more than solids. To determine hardness, a device with a punch is used, the tip of which is pressed to the depth of the radius. At the end of the procedure, a trace remains in the raw material. Hardness is determined by the size of the mark. Impact hardness is calculated by dropping a metal ball with a diameter of 25 mm from a height of 50 cm onto a specimen.
The ability of lumber to resist wear is called wear resistance. It has long been known that wear on the side parts is much higher than on the end cuts. As hardness increases, wear decreases. Wet timber is more susceptible to wear and tear than dried timber.
Perhaps the most unique quality of lumber is the ability to hold fastening materials such as nails, screws, and staples. When driving a nail into the raw material, elastic destruction is created, providing the necessary friction force. It is this that prevents the nail from being pulled out. With increasing density, the resistance of timber to pulling out of fastening material increases.
Oak and ash lumber is much easier to bend than, for example, beech. Coniferous varieties are characterized by even less bending ability. It is much easier to bend timber when treated with steam. Such conditions make the raw material more pliable and make it possible, as a result of the formation of frozen destruction during further cooling and drying under load, to consolidate new uniform sample.
To compare the qualities of timber of different types, experts use specific coefficients mechanical properties, i.e. coefficients of their mechanical properties, proportional to the unit of density.
These lumber indicators are very important if an object or structure is required increased strength at low weight. All this is necessarily taken into account in transport engineering, aircraft construction, and shipbuilding.
The most strong trees in the world
Today, the hardness of wood is determined using several methods. There are ratings of all trees by density. Based on hardness, they determine where and what kind of wood to use.
The hardest woods
Based on the hardness data obtained, a list of the hardest trees has been compiled. I entered it white acacia. This tree grows in large quantities in Europe, where it came from North America.
Brazilian cherry, scientifically called Jatoba, is in second place in terms of hardness. It should be noted that this tree has nothing in common with plants of the “cherry” genus. IN South America Sucupira grows. Its wood is not only practical, but also decorative, as it has interspersed light veins that contrast with the reddish-brown wood. It is known that fungi and pests are not dangerous to succupire. Despite the fact that wood is difficult to process, it can be sanded well.
There is such a hard wood as African turbidity. The unusual thing is that its structure is similar to teak, and its color resembles walnut. IN Central America there is a tree amaranth, which has dense but flexible wood with a red-violet hue and a large, expressive structure. Amaranth is difficult to process and varnish, and individual accessories and expensive furniture are made from its wood.
Merbay- another type of hardwood. It is easy to process, easy to polish and resistant to moisture. These properties make it ideal for the production of parquet and bathroom decoration. The well-known Canadian maple growing in North America, another name for sugar maple. This solid tree is a symbol of Canada.
Yarra- Australian eucalyptus. Due to the similarity of its wood to mahogany, the tree is also called Australian mahogany. Wood is considered hard rosewood. His homeland is Brazil. It is an indispensable material for the manufacture of musical instruments and furniture for presentable objects.
Next on the list is ash with very hard wood, behind it - oak, with heavy and durable wood. It is impossible not to say about bouquet. The properties of its wood allow it to be widely used.
The hardest tree in Russia
Russia is rich in forests. Birch Schmidt- a resident of the Kedrovaya Pad nature reserve, located in Primorye, is the hardest in the country. This birch is one of the representatives of the so-called iron trees. Due to the extremely hard wood, bullets bounce off it, it instantly sinks in water, has the property of self-preservation, does not rot and is stronger than cast iron. It is believed that bearings for cars can be made from this tree..
Birch got its name in honor of the botanist named Schmidt who discovered it. This tree grows on the slopes of ravines near rocky outcrops, as it loves rocky soil. Birch always has an inclined trunk. Usually it is comb-shaped and does not exceed eighty centimeters in girth. The iron birch reaches a height of twenty-five meters, but the crown begins only at a height of eight meters. These trees are considered long-lived. On average, the Schmidt birch lives about three hundred and fifty years.
What is hardwood made of?
Hardwoods have many uses, depending on the species. So, canes, billiard cues, furniture, and parquet are made from Brazilian cherry, which is called jatoba. But this wood is not used in shipbuilding, as it deteriorates in sea water.
Acacia wood has a yellow tint. It was also known to cabinetmakers because it does not rot or wear out. Parquet is made from acacia wood, which is considered stronger than oak, and it becomes more beautiful over the years.
Marbau wood, due to its increased hardness, is used during construction public buildings, and also make parquet out of it. It is used when decorating wet rooms, as it is not afraid of water.
From durable wood ash was previously used to make not only hunting tools, but also military weapons, made spears and clubs. It is known that when beech wood is steamed, it bends easily. This property is indispensable in the manufacture of furniture. round shape, including Viennese chairs. Beech is used to make gun butts, weaving shuttles and even musical instruments. In addition, plywood and containers are made from beech, beech parquet and measuring instruments are known.
The tree with the strongest wood
It is reliably known that the strongest, in other words “iron” wood is from trees that are called “iron trees”. It is so strong that it sometimes exceeds iron in this indicator. You can even make nails and machine parts from it. There are several such types of trees and they grow in different parts planets. Here are some examples of these miracle trees.
Birch Schmidt, whose wood is one and a half times stronger than cast iron, grows in the Primorsky Territory; another owner of iron wood grows in Brazil - this Amazon tree, in Africa such a representative is called azobe. Taxus (or yew) also belongs to the iron trees, it is absolutely not susceptible to rotting, it is also called “non-rotary wood”. Azerbaijan and Iran - homeland iron wood entitled Temir-Agach, and in the Northern Irish and Transcaucasian forests it grows Persian parrotia.
The trees are record holders not only in strength, but also in size. According to some data, the most a big tree in the world has reached a height of more than 150 meters.
The main parameters by which industrial wood is selected for furniture production: strength, resistance to deformation, wear resistance. All these three qualities are combined into one indicator - wood density, that is, the ratio of the mass of the tree to its volume.
Types of wood depending on density:
A) Soft (up to 540 kg/m3) – spruce, pine, aspen, linden, fir, poplar, chestnut, alder, cedar;
B) Hard (550-740kg/m3) – larch, birch, oak, elm, beech, sycamore, Walnut, maple, apple, ash;
C) Very hard (from 750 kg/m3) – iron birch, rowan, white acacia, hornbeam, dogwood, boxwood, pistachio tree.
Let's consider the breeds most in demand in furniture production:
1. Pine
Wood color– brown, beige-yellow, white with light pink streaks. The best material for making furniture is considered to be pine trees growing on hills with sandy soils or on dry hills. In such wood, the annual layers will be pronounced and narrow, close to each other. Pine grown in an area with high humidity will have a loose structure, and blanks from it will have to be dried for a long time before being put into production. Pine wood is soft, easily scratched and damaged.
Pros:
- flexibility in processing. Pine is easily planed along the grain, but difficult to plan in the transverse direction. When cutting, the opposite is true—a log cuts across easily, but poorly along lengths.
- easy to glue;
- depending on the color and structure of the wood, pine is used both for making furniture with subsequent varnishing, and for frames, and various designs with hardwood veneer veneer;
- like all conifers, it has a pleasant smell and releases phytocindes, which are considered medicinal.
2. Spruce
Spruce wood is softer than pine. In addition, the trunk contains a large number of knots that make it difficult to process wood for the manufacture of furniture panels. Compared to pine, spruce absorbs moisture better and begins to rot faster. Due to its inexpressive texture and low strength, spruce is most often used for mosaic finishing or in structures that do not experience significant loads during operation.
Pros:
- spruce wood is practically not subject to warping;
- sticks well.
Along with spruce it is also used Siberian fir- these two trees have similar indicators.
3. Larch
The wood of this coniferous tree valued for its unusual reddish-brown hue and high performance. From disadvantages of larch– a large amount of resins, which quickly damages tools and causes difficulties in processing. If improperly dried, internal cracks form on larch wood.
Pros:
- high moisture resistance;
- excellent strength indicators (the best among conifers);
- little susceptible to warping;
- used for making carved parts.
4. Cedar
Yellowish-white cedar wood is not very strong and dense, so it cannot withstand heavy loads.
Pros:
- resistance to rot and wormhole;
- suitable for carving;
- has a specific woody aroma.
5. Yew
Red-brown with light and dark veins, yew wood is highly durable, but also big amount knots.
Pros:
- not subject to wormhole,
- easy to plan and sand,
- insensitive to atmospheric changes.
6. Oak
On a radial section of an oak trunk, large pith rays and light sapwood are clearly visible. Oak is the most widely used hardwood in the manufacture of solid wood furniture, due to its excellent combination of strength and beautiful texture. If an oak tree lies in water for a long time (several decades), its wood acquires a rare dark purple color with a green tint. Oak wood is difficult to polish and requires equipment with highly hardened cutters.
Pros:
- despite the high viscosity of wood, it is processed quite well;
- bends easily;
- resistant to rotting;
- lends itself well to artificial aging techniques.
7. Ash
Wood for many qualities looks like oak, but lighter and does not have pronounced medullary rays. Ash must be subjected to antiseptic treatment, since in humid conditions the wood is quickly damaged by wormholes. Poorly polished.
Pros:
- bends well after steaming;
- cracks little when dried;
- when bleached, it acquires an unusual shade of gray hair.
8. Beech
Beech wood strength is not inferior to oak, but is highly hygroscopic, so it is not recommended for the manufacture of furniture that will be used in high humidity(bath, kitchen). Poorly polished.
Pros:
- high decorative qualities: beautiful texture both in radial and tangential cuts,
- quick to dry, does not crack;
- easy to process: pricks, saws, cuts, bends;
- It is perfectly bleached and painted using special solutions - it practically does not change the beautiful natural shade when varnishing.
9. Hornbeam
It has hard, dense wood of a grayish-white color. It is often called white beech, but hornbeam has a less pronounced texture and often has a cross-ply structure, which makes the tree difficult to split.
Pros:
- after proper drying, the hornbeam becomes harder than oak;
- not subject to warping;
- lends itself well to etching and finishing.
10. Common birch
Birch wood, despite its high density, is not resistant to rotting, therefore it is used primarily for the manufacture of plywood, peeled veneer, and chipboard. It takes a long time and doesn’t dry well, is susceptible to wormholes, cracks a lot, and warps.
Pros:
- homogeneous structure and beautiful colour wood;
- bends well;
- in the production of solid wood furniture it is used as an imitation valuable species(stains well when etched).
Karelian birch is distinguished separately, which has higher performance indicators, is known for its unusual texture and pink wood It is expensive, so it is used mainly for veneering solid wood furniture.
11. Maple
Despite the fact that it is dense Maple wood rarely cracks, He not resistant to dampness. Bird's eye and sugar maple are the most prized maples because of their characteristic beautiful structure.
Pros:
- easy to prick, well processed: cut, polished;
- has a homogeneous structure without pronounced fibers;
- when painted, it successfully imitates valuable species;
- Maple wood does not have a pronounced core, so it is easily painted, varnished, and stained.
12. Alder
Soft breed, without a pronounced structure. Alder wood quickly darkens in air, so it is used mainly in painted form (black or mahogany). Feature of alder: susceptible to wormhole in dry places, but resistant to rot in wet conditions.
Pros:
- dries quickly,
- easy to carpenter,
- polishes well
- warps slightly.
13. White acacia
The hardest hardwood, therefore has high resistance friction and is elastic. In dry form it is difficult to process, so it is used mainly for facing soft rocks.
Pros:
- perfectly polished;
- When exposed to air, the wood darkens, causing the texture to acquire a bright yellow-brown color and expressive texture.
14. Walnut
How older tree, the more valuable and darker its wood. The most expensive variety is American black walnut.
Pros:
- a wide variety of shades;
- dense but malleable wood;
- easy to paint, thanks to the high content of tannins (from tinting under ebony until smooth white).
15. Linden
It is used in production for the production of figured turned elements. It contains few tannins, so it practically does not stain, but it can be stained very well (with the correct concentration of the solution, linden wood can be given the appearance of more valuable tree species). Needs antiseptic impregnation, as it is highly susceptible to wormholes.
Pros:
- resists moisture well,
- wood is durable and plastic,
- has a beautiful white and creamy hue.
As you can see, each wood has its own advantages and disadvantages, based on which you can choose a certain type for making furniture from solid wood.