A tree is one of those building materials,which are known to mankind since ancient times. Volumes of its consumption grow every year, and therefore many species are on the verge of total extinction.
It refers to the genus of oaks. The difference from relatives is that by about five years, its branches and trunk are covered with a thick bark with unique properties. But you can shoot it only by the age of 20. Note that this can be done up to the age (tree, of course) 200 years!
After the first collection, it takes at least 8-9 years, during which the bark is regenerated. A tree aged 170-200 years gives about 200 kg of high-quality raw materials.
The peculiarity of this oak is also that itrefers to evergreen species. The leaves resemble those of Russian oaks, but the bottom is covered with a considerable layer of down. The cork tree itself is quite large: the height can reach 20 meters, and the diameter of the trunk is a meter.
The Latin name is Quercus suber. It grows at a height of no more than 500 meters above sea level. Most of all oaks of this species are found in Portugal, which causes the country's budget to receive large cash inflows, resulting from the export of cork, which annually increases its value.
A man from ancient times knew that a cork tree givesthis is a valuable raw material, but because it has long been cultivated culturally. Note that there is a false representative of this genus, Q. crenata, which is fairly widespread in southern Europe. The cork layer is so small that the tree is bred exclusively for decorative purposes.
Only in Portugal the plantations of oak Quercus suber employ more than 2 million hectares! In addition, approximately the same number of territories is used for this purpose throughout Southern Europe.
For a year all plantations give more than 350 thousand tonsbark, but this amount has long been in short supply to meet demand. That is why the wild-growing cork tree was almost completely destroyed.
By the way, what is the uniqueness of cork as a material? The fact is that it is a natural polymer, the structure of which resembles a honeycomb in a bee hive.
Each cubic centimeter of this material can contain up to 40 million such honeycombs, which are delimited between themselves by means of partitions from 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 full water resistance and the ability to restore the original state even after strong pressure.
In addition, the composition of the cortex includes suberin (thismixture of fatty acids, waxes and alcohols). It is unique in that it gives the wood refractory and antinoise qualities. There are cases when, in forest fires, the cork oaks remained completely intact, except for the scorched cortex and dried leaves from the heat.
Thus, the bark of the cork tree is a unique material, given to man by nature.
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