Cork tree: description. Amazing properties of the bark. Technical traffic jam. Material Features, Characteristics and Application Bark Harvesting Process
Fellems. First, a layer of phelloderm cells is formed, which forms a layer of phellogen cells. Phelogen cells are divided into two parts: upper and lower. The upper cell (fellema) immediately dies and is covered with a thick layer of suberin (a substance that does not allow water and gases to pass through). The lower cell continues to divide, forming a phellem. In some plants (for example, pine, tulip tree, euonymus), the cork consists of thin-walled corky cells and phalloids - cell layers with lignified, but not corked walls.
The cork performs the following functions:
- protection against mechanical damage,
- protection against the penetration of pathogens,
- dry protection,
- mechanical support due to the rigidity of the phellem cells.
see also
Notes
Literature
- Biological Encyclopedic Dictionary / Ch. ed. M. S. Gilyarov; Editorial: A. A. Baev, G. G. Vinberg, G. A. Zavarzin and others. - 2nd ed., corrected. - M .: Soviet Encyclopedia, 1989. - S. 506. - 864 With. - 150,600 copies. - ISBN 5-85270-002-9
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See what "Cork (biology)" is in other dictionaries:
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Wood is one of those building materials that have been known to mankind since ancient times. The volume of its consumption is growing every year, and therefore many species are on the verge of extinction.
The latter also includes the cork tree, which has been used by man for thousands of years.
It belongs to the genus of oaks. The difference from relatives is that by about five years of age, its branches and trunk are covered with thick bark with unique properties. But you can only take it off by the age of 20. Note that you can do this up to the age (tree, of course) of 200 years!
After the first collection, at least 8-9 years are required, during which the bark is restored. A tree aged 170-200 years produces approximately 200 kg of high quality raw material.
The peculiarity of this oak is also that it belongs to the evergreen species. The leaves resemble those of Russian oaks, but are covered with a significant layer of down below. The cork tree itself is quite large: the height can reach 20 meters, and the diameter of the trunk is a meter.
Latin name - Quercus suber. It grows at an altitude of no higher than 500 meters above sea level. Most of the oaks of this species are found in Portugal, which is why the country's budget receives considerable cash injections from the export of cork, which annually increases its value.
Since ancient times, man has known that the cork tree provides this most valuable raw material, and therefore it has long been cultivated culturally. Note that there is a false representative of this genus, Q. crenata, which is quite widespread in southern Europe. Its cork layer is so small that the tree is bred exclusively for decorative purposes.
Only in Portugal more than 2 million hectares are occupied by Quercus suber oak plantations! In addition, approximately the same number of territories are used for this in all of Southern Europe.
During the year, all plantations produce more than 350 thousand tons of bark, but this amount has long been insufficient to meet demand. That is why the wild cork tree was almost completely destroyed.
By the way, what is the uniqueness of cork as a material? The fact is that it is the structure of which resembles a honeycomb in a beehive.
Each cubic centimeter of this material can contain up to 40 million of these honeycombs, which are separated from each other by partitions of the cellulose component.
Simply put, each capsule is filled with air, so that even a small piece of cork is very elastic. This property gives the material complete water resistance and the ability to restore its original state even after strong pressure.
That is why the cork tree (whose photo is in the article) has received such wide appreciation from furniture makers.
In addition, the bark contains suberin (a mixture of fatty acids, waxes and alcohols). It is unique in that it gives the tree refractory and anti-rotten qualities. There are cases when, during forest fires, cork oaks remained completely intact, with the exception of scorched bark and leaves dried from the heat.
Thus, the bark of the cork tree is a unique material given to man by nature.
In our modern times, construction keeps pace with the times. There are many kinds of finishing materials in the world. Today we will talk about a tree that gives us such a wonderful material as cork. It has been used by people since ancient times, not only in construction, but also in industry. The bark, which after proper processing turns into a cork, is formed in many plants.
In large quantities, sufficient for industrial use, it can be obtained from only three trees: the Amur cork tree (Amur velvet), Chinese variegated oak and cork oak. Cork is the top layer of the bark with deep cracks. Thanks to its dead cells, impregnated with suberin, it does not allow water or gas to pass through. It is worth getting to know the cork oak, which gives such a desired product.
Cork tree: description
From this plant it exudes strength, because oak has been considered a symbol of power and greatness since ancient times. The cork tree grows up to 20 meters in height. The crown is in the form of a tent with powerful branches. In plantations, this plant acquires a cylindrical shape.
The bark on thick branches and trunk is covered with an impressive cork layer. The cork leaf is oval or elliptical, 4-7 cm long and 1.5-3.6 cm wide. Leaves can be with small sharp teeth or entire. The top is shiny green, the bottom is gray densely pubescent. Leaves live 2 years, then fall off.
Acorns ripen on a short fruiting 2-3 pieces. In the first year of a tree's life, it is already possible to harvest acorns. Their size is about 3 cm in length and 1.5 cm in diameter. The plush is gray-pubescent and is 1/2-1/3 the size of the fruit.
cork bark
Cork oak is capable of regenerating bark layers. Cork formation is very slow, in one year it grows to approximately 7-8 mm of valuable layer.
An oak with such an unusual bark grows in areas with extremely hot and dry climates. By rewarding this plant with a cork layer, nature made sure that it was protected from overheating and drying out. Everyone knows how hot and merciless the subtropical sun can be.
Cork oak bark has small pores that contain air, so it is considered a wonderful insulator and protective layer of the plant.
Where is cork oak found in nature?
The cork tree grows in the wild in the coastal belt of Portugal. This country is rightfully considered the leader in cork production. It is here that the greatest variety of products from this raw material is observed. You can buy anything: a bag, wallet, shoes, souvenirs... It is also known that in 2010 a bride ordered a wedding dress made of cork, in which she walked down the aisle.
Amazing oak plantations are located in Italy, Spain, Morocco, France, Algeria and Tunisia. These plantations occupy an area of about 2-2.5 million hectares. Every year, the owners of cork plantations harvest 300-360 thousand tons of cork.
The process of harvesting the bark
Harvesting bark is a very complex and time-consuming process. Collectors must climb ladders to a great height in order to find a layer of at least 3 cm. Having found the right place on the tree, the worker makes a cross cut of the cork around the circumference of the trunk, the same is done below. Then the top and bottom are connected with one cut going from above, a wooden device is inserted between the dead bark and the bast, and the cork layer is very carefully separated.
The collected raw materials are stacked in special rooms for drying, where they are stored for several weeks, awaiting the next stage of processing.
On industrial plantations, the first crop of bark is harvested from fifteen-year-old trees. The best raw cork can be obtained from oak aged 30 to 150 years. Only after the third harvest is the bark of the highest quality.
The process of removing the bark is traditionally considered manual, this occupation was practiced a thousand years ago. The cork tree does not suffer from such processing if everything is done carefully and correctly. The bark grows back over time and becomes smoother every year, which increases its value. Harvested once every ten years. If we take into account the fact that this plant can live up to 200 years and even longer, then cork is collected about twenty times during its life.
Industrial use
As mentioned earlier, cork bark has been successfully used by mankind since ancient times. The peoples of the Mediterranean made shoes from cork and used it in the manufacture of gear. Our ancestors also clogged vessels with wine, water, vinegar and oil with it. The chroniclers of Ancient Rome in their descriptions talk about the use of cork bark in the construction of prefabricated housing as an excellent heat insulator. Such material was especially appreciated in field conditions.
In the modern world, cork raw materials have become even more popular. Cork is valued as an interesting finishing and building material. Wallpaper, linoleum, parquet, panels are made from it... Light and strong soles, rescue water tools, souvenirs are also made from this amazing bark... Cork is of considerable importance for winemakers. After all, only through such a high-quality blockage can wine breathe for many years.
Phellema (phellema), the outer part of the secondary integumentary tissue of a plant - the periderm. It develops from phellogen (cork cambium) cells during their division in the tangential direction (parallel to the surface of the axial organ). Biological encyclopedic dictionary
