Cork layer of wood. Cork oak is an amazing tree and its features. How to cut a cork

Fashion & Style

I intend to show how information borrowed from encyclopedic sources and implemented in literally, for example, to obtain cork products, can lead to the death of plants. After analyzing the above terms, I offer the appropriate clarifications. I express the hope that this work will be useful for the same specialists; for entrepreneurs who want to resume the cork processing industry in Russia using domestic raw materials; for forest growers who have decided to resume the cultivation of the domestic cork tree and to promote, by multiplying the cork resource base, the implementation of the true rules of biological construction; for consumers of cork products in various industries - from space technology to winemaking, sports, etc.; for readers who want to broaden their horizons.

It is appropriate to recall that ninety years ago, our society, which refused to study the so-called dead languages (Latin and Ancient Greek) in the system of secondary education, made a giant leap ... backwards in the process of familiarization with the universal culture. It should be recognized that the language of the nation promotes communication and unity of a certain group of people, and dead languages are the feeding root system giant tree Indo-European languages.

Amur velvet cut

It is difficult to imagine the realities of those distant years, but their negative consequences are manifested even today. Surely anyone can independently answer the question: what level of knowledge did university graduates of those times have, if we recall that most of the youth "mastered" the program high school for 3 years (for 4 - on the job) and without exams enrolled in any institution? But among the Rabfakovites there were also those who had passed the educational program (courses for the elimination of illiteracy). What kind of Greek, especially ancient, are we talking about here?

But the vast majority of proletarian peers of the beginning of the last century - our grandfathers and fathers - passed through the system of workers' faculties (1919 - 1939). old world turned out to be destroyed to the ground, and whoever was a nobody ... However, the result of the activities of the former worker former head of our state, the current president of Russia is defined as "stinking Khrushchev". That is why today a full-fledged Russian specialist, who has an impeccable command of terminology, and it is based mainly on dead languages, is more likely to be understood in Europe and overseas than in his own country. And it's sad to admit it. Based on the foregoing, I apologize to botanists and dendrologists for the fact that, for the sake of clarity, special terms will be omitted: periderm, phellogen, phelloderm, epiderm, meristem, xylem, phloem, tracheids, sclereids, etc.

As a final preface, a household anecdote. One corresponding member of the Russian Academy of Agricultural Sciences on a bet (100 US dollars) was going to show a dictionary interpretation of the concept of cork noses, but, to his great surprise, he could not find this word even among 160 thousand units of the Russian Spelling Dictionary (Moscow, 1999).

Cork oak bark at the border of cyclic removal

True, the second debater did not risk anything, since his previews of dictionaries of botanical terms in the library of the Botanical Institute of the Russian Academy of Sciences (St. Petersburg) for more than a hundred years (from Petunnikov A., 1898) did not reveal either the word or its semantics used in the scientific literature at least since the end of the 20s of the last century (Kern E.E., 1929) for many decades (Krechetova N.V., 1986) without comment. Only one author ventured to give an unstandardized definition: "cork-bearing plants are those that produce raw materials consisting of cork tissue and are used mainly as a sealing and insulating material" (Nikitin A.A., 1950). Obviously, the author borrowed an analogy in the definition of industrial crops that are raw materials for industry: rubber, medicinal, oil-bearing, honey, spinning, ether-bearing, sugar-bearing, etc. Perhaps this borrowing came from a desire to simplify the situation.

The absence of the normative concept of cork noses in dictionaries, in my opinion, can be easily explained if you get acquainted with the dominant word cork. According to encyclopedic data, cork is a secondary integumentary tissue of plants, consisting of polygonal microcells that are tightly adjacent to each other (without intercellular spaces) and die off when ripe.

The process of death is accompanied by corking, that is, cell membranes are impregnated with a wax-fat-like substance (suberin), which makes them impermeable to gas and water vapor. The shells of cork cells typically consist of several layers: the median lamina (a layer of intercellular substance), the cork (suberin) lamina, and the cellulose layer adjacent to it from the inside of the cell, often lignified. The qualities of suberin, unique in no substance, have been known since 1815.

Actually, the phenomenon of cork formation in nature is very common, even more common than we imagine. Cork can occur in both woody and herbaceous plants. Moreover, the cork is formed on various organs: in woody plants, as well as in most perennial herbaceous plants - on stems and roots; in annuals - in the hypocotyl knee and on the roots.

The same sample from the side of the previous removal

The role of cork in the life of plants is great and diverse: it protects against excessive evaporation of water, from damage by bacteria, fungi and insects, from mechanical damage, as well as from the effects of temperature - overheating and hypothermia. One of the special functions of cork is the healing of various damage to plant tissues, the so-called wound plug. The latter can be observed with the naked eye, for example, on a cut potato tuber. It is curious that the same cork is the cause of leaf fall. Under certain conditions, at the point of attachment of the leaf stem to the branch, an intensive accumulation of cork occurs, metabolism decreases, mechanical bonds weaken and the leaf can come off due to its weight. One scientist even made calculations showing that about 33,000 kg of leaves are annually dumped on the ground per hectare of a forty-year-old birch forest (Kern E.E., 1929).

There is very little left: to find out the proportion of cork in this solid mass and how to extract it from there ...

Thus, the presence of cork in a plant does not allow it to be mechanically attributed to industrial crops, and therefore the use of the non-standardized concept of cork-bearing plants should be recognized as incorrect.
Let's understand the term cork products. How were they obtained, how did the cork get into them? The apparent answer is given by an extensive reference literature. I will quote only a few sources, arranging them in chronological order to illustrate the process of clarifying the concept.

The "Explanatory Dictionary of the Great Russian Language" contains the following notes: "cork, made of cork, bottle cork, cork oak bark, Quercus suber, cork stopper" (Dal V.I., 1866).
"Cork-bearing plants of the USSR": "the main cork-producing plants are cork oak, western or Portuguese oak (Q. occidentalis), false cork oak (Q. pseudosuber), variable oak (Q. variabilis), Amur cork tree (Phellodendron amurense Rupr.), Japanese velvet tree (Ph. Japonicum).The formation of cork layers is also noted: in cork birch bark (Ulmus suberosa), leafy elm (U. foliaceae), rough elm (U. scarba) (Nikitin A.A., 1950 ).

View from the side of the subsequent removal (after 9 years)

"Big soviet encyclopedia", v. 34: "cork products are products made mainly from the bark of a cork oak and partly from the bark of a velvet tree" (Moscow, 1955).
The "Historical and Etymological Dictionary of the Modern Russian Language" explains: "Cork - 1. Bushing, plug (in the neck of a bottle or in the hole of some other vessel, apparatus) ... 2. Material obtained from the bark of a cork oak."

“In Russian, the word cork has been known since the beginning of the 18th century in the meaning of “a plug on the hole of a tool” in the form of probes. modern meanings it has been noted in dictionaries since 1782 (Chernykh P.Ya., 1994).
"Modern dictionary Russian language" gives, in my opinion, a more approximate interpretation: "Cork, 1. The outer layer of the bark of some woody plants (mainly cork oak. Light and soft porous material obtained from such bark" (Kuznetsov S.A., 2004).

I note the commonality of all sources: to produce a cork product, raw materials are required, which are obtained by “peeling off” the bark (Nikitin A.A., 1950), containing the cork, from a certain tree. The search for a milder treatment of the plant led to the replacement of "stripping" with "barking" ("Russian Spelling Dictionary", 1999). Unfortunately, with close acquaintance, this term did not satisfy my topic; wood debarking - cleaning wood from bark. Barking is subjected to the so-called. pulpwood, as well as mine racks and ridges for the match industry "(TSB, vol. 30, 1954). Therefore, I had to turn to the scientific and technical literature for clarification in order to understand the technology for removing the bark or its part and why few are able to endure this operation trees are almost painless.For clarity of presentation, I suggest sections of cork oak (Fig. 1) and Amur velvet (Fig. 2).

From the works (Ioelson M.D., 1894; Kern E.E., 1928; Yakimov Yu.K., 1934; Popov V.V., 1935; Tsimek A.A., Emashev S.D., 1952) follows that the trunk of a tree (cork oak or Amur velvet) consists of wood and bark. The bark, in turn, contains two clearly separated layers: the inner one, bast, adjacent to the wood, and the outer one, cork, cut through with cracks. The bast (mother) layer up to 15 mm thick for velvet and up to 50 mm for cork oak consists of long fibers and serves to carry nutrients from the branches down the trunk. The outer cork layer (crust - according to the definition of the "Small Biological Encyclopedia", edited by Prof. P.Yu. Schmidt, 1924) consists of dead cells and is up to 70 mm thick or more (Fig. 3). The purpose of the peel is to protect the tree from frost, overheating and other external influences.

A significant difference from known plants, in the bark of which cork is present (except for mistletoe and the Cornegio cactus), but is inaccessible to humans, is that only cork oaks and Amur velvet have a thick crust and are quite thick. bast layer. At the boundary of these layers, mechanical bonds are very weak (!!!). It is precisely because of this that these trees allow at a certain time through certain cycles to remove the corked part of the bark (crust) from themselves to the bast (mother layer). The bast for the first time after removing the peel protects the tree from the sun, withering winds, temperature changes, etc .; in place of the removed plug, a new one quickly grows, which, in terms of consumer properties, improves from removal to removal (Fig. 4).

It is known from practice that it is the insignificant thickness of the bast layer that also determines its lower regenerative functions. Therefore, if you remove the bark from a plant without even touching the bast, then it, as a rule, will die. The consequences of collecting cork outgrowths from elms according to the methods described by A.A. Nikitin (1950); cutting off branches and beating them with mallets, manually breaking off the bark with outgrowths, manually breaking off the outgrowths and cutting off the outgrowths with a knife. "And although the latter method, according to the author, turned out to be the most effective: up to 2 kg of cork can be collected per day, all these methods must be classified as barbaric, and it is obvious that a reasonable person should not act in such a way.

1 - end section; 2 - radial section; 3 - tangential section

1 - core; 2 - core rays; 3 - core; 4 - cork layer; 5 - bast layer; 6 - sapwood; 7 - cambium; 8 - annual layers.

Sapwood and heartwood

Studying the macroscopic structure of wood, it can be found that in some species the wood is colored evenly, while in others central part darker than outside. The dark-colored part is called the core, and the outer light zone is called sapwood. In some species, the central part, not differing in color from the outer, contains (in a growing tree) significantly less water and is called mature wood. Species with a core are called sound, and rocks with ripe wood are called ripe wood. If there is no difference in color or water content between the central and peripheral parts of the wood, then the rocks are called bleached.

It is believed that the core is formed in all breeds, only in some of them its dark color always appears or under certain conditions, while in the rest it remains light. Therefore, mature wood is an unpainted core.

The colored core among conifers has larch, pine, cedar, yew, juniper; among hardwoods - oak, ash, elm, elm, elm, walnut, poplar, willow, mountain ash, etc. Sapwood includes many hardwoods - birch, alder, linden, hornbeam, maple, boxwood, pear, hazel, etc. Ripe spruce and fir have wood among coniferous species, and beech, aspen and some others among deciduous species.

At an early age, the wood of all species consists only of sapwood, and only over time does a core form in some species. In some species, the formation of the core begins early (in oak, for example, in the 8-12th year) and the sapwood is narrow. In other species, the core is formed much later (in pine at the age of 30-35 years), which leads to the presence of a wide sapwood. The transition from sapwood to heartwood can be abrupt (yew) or gradual (walnut). With age, the diameter of the trunk increases, and the proportion of the core increases due to the transition of part of the sapwood into the heartwood. So, in an oak, the volume of the core with a trunk diameter of 15 cm is approximately 50% of the volume of the sapwood; with a diameter of 30 cm, the core is 3-5 times larger than the sapwood in volume, and with a diameter of 60 cm, the sapwood accounts for only 10% of the volume of the core.

The size of the sapwood depends on the growing conditions. So, in oak, the widest sapwood is observed in the trunks of trees growing on solonetzic soils, and the smallest - in floodplain oak forests. In pine trunks from the Komi Republic, the relative content of sapwood increases with the deterioration of growing conditions. The width of the sapwood along the height of the trunk in conifers (pine, spruce) gradually decreases, while in oak it remains almost unchanged; at the same time, the proportion of stem cross-sectional area to sapwood increases up the stem. For pine from the Komi Republic and Krasnoyarsk Territory the width of the sapwood increases with age, and after 100-120 years it begins to decrease, mainly due to a decrease in the width of the annual growth of wood.

In a growing tree, the sapwood serves to conduct water up the trunk (from the roots to the crown) and to deposit reserve nutrients.

The formation of the nucleus depends on the breed, age, growing conditions and other factors; to a certain extent, it is associated with the vital activity of the crown. The process of nucleation consists in the death of living elements of wood, blockage of waterways, deposition of resin and calcium carbonate. The wood in this zone is impregnated with tannins and dyes, as a result of which it darkens, its density slightly increases, and resistance to decay increases.

Due to the blockage of the waterways, the wood of the core is not very permeable to water and air, which is positive when making containers for liquid goods from wood and negative when impregnating wood with antiseptics (the core is usually not impregnated). In a growing tree, the core gives stability to the trunk, at the same time, the core can serve as a storage for water (oak, elm).

annual layers. Every year a layer of wood is deposited on the trunk. Schematically, the trunk can be represented as a system of cones mounted one on top of the other. If the lower cross section shows ten concentric semicircles, and the upper one shows five, then it took 3 and 8 years, respectively, for the tree to reach the height at which the cross sections were made. On a transverse section, the annual layers look like concentric annular bands of different widths.

Annual layers are noticeable in many species, but especially well in conifers. On the radial section, the annual layers have the form of longitudinal parallel stripes, and on the tangential section, they look like sinuous 11-shaped strips.

The width of the annual layers varies greatly depending on many factors: breed, age, growing conditions, position in the trunk. The narrowest annual rings (up to 1 mm) are formed in slow-growing species (boxwood), and the widest (1 cm or more) are characteristic of rapidly growing species (poplar, willow). In the trunk of a tree, the annual layers are wider than in the branches. At a young age and under favorable growth conditions, wider annual layers are formed.

Along the radius of the trunk, the width of the annual layers does not remain constant and changes as follows: at the core there is a number of relatively narrow annual layers, then a zone of wider layers follows, and further towards the bark, the width of the layers gradually decreases. The area of the annual layer first increases quite rapidly in the direction from the core to the cortex, reaches a maximum, and then gradually decreases.

The intensity of annual growth is influenced by the peculiarities of the meteorological conditions of a particular year, and long-term climate changes can be traced by the width of the annual layers. These questions are considered by the scientific discipline dendroclimatology. By examining the width of the annual layers and using dendrochronological scales compiled for different regions of the country, it is possible to determine the time of manufacture of wooden products and structures. The dendrochronological method (V. E. Vikhrov, B. A. Kolchin) found wide application for dating archaeological finds made of wood.

Along the height of the trunk, the width of the annual rings normally increases from the butt to the top, which makes the trunk full-wood, i.e. close in shape to a cylinder. However, free-growing trees have the widest annual rings in the lower part of the trunk, which gives the trunk a cone shape (tapered trunk).

In some species, undulations of the annual layers are observed in the transverse section, for example, in the hornbeam, yew, juniper; in beech and alder, the boundary between the annual layers at the places where it is crossed by wide medullary rays (see below) is bent inward (toward the core), which also gives the layers a wavy appearance.

Annual rings on opposite sides of the trunk are sometimes unequal in width; if such unevenness extends to a large number of neighboring annual layers, then the trunk acquires an eccentric structure, the cause of which is often the uneven development of the crown and root system (edge trees) or the action of the wind, causing the trunk to bend. Especially clearly visible eccentric structure in the side branches; in hardwoods, the core of the branch is shifted closer to the underside, and in conifers - to the top.

In many species, it is clearly seen that the annual layer consists of two parts: the inner, lighter-colored and softer part facing the core, the early wood (it forms in the first half of the growing season), and the outer, darker and harder part facing the bark, - late wood. The difference between early and late wood is more pronounced in softwoods (especially larch) and to a lesser extent in many hardwoods, so the annual rings are clearly visible in softwoods and often poorly visible in hardwoods.

In a growing tree, water moves up the trunk along the early wood of the annual layers, and the late wood performs mainly mechanical functions. Depending on the species, age, growing conditions, position in the trunk, the ratio between early and late wood can vary greatly.

In coniferous species, the content of late wood in the annual layers in the direction from the core to the bark first increases, reaches a maximum, and then decreases in the layers located closer to the bark. According to the height of the trunk, the content of late wood decreases in the direction from the butt to the top and can decrease by 1.5-2 times.

The properties of early and late wood of the annual layer are significantly different. In some breeds, the differences are especially pronounced. For example, in larch and oak, according to V. E. Vikhrov, late wood is denser than early wood (2.3 and 1.5 times, respectively), dries out more (1.8 and 1.4 times), is stronger in tension ( 3.4 and 2.3 times).

In spruce, according to I. S. Melekhov, the tensile strength along the fibers of late wood is 2.7 times greater than that of early wood. The stiffness of late wood is also significantly higher than that of early wood. Since late wood is denser, stronger and darker than early wood, the density, strength, and also, to a large extent, the color of the wood as a whole depend on the amount of late wood.

core rays. On the cross section of some species (for example, oak), light shiny lines are clearly visible, diverging from the core to the bark along the radii and called core rays. Core rays are present in all types of wood, but only in a few species are they so wide that they are clearly visible in a cross section with the naked eye.

The width of the core rays, measured on the cross section of the trunk, varies depending on the breed from 0.005 to 1 mm. Three types of beams are distinguished by width:

1) very narrow, invisible to the naked eye;

2) narrow, hard to see with the naked eye;

3) wide, clearly visible to the naked eye.

The latter can be true or false wide (aggregate), i.e. consisting of a bundle of closely spaced narrow rays.

Real wide beams have oak, beech and sycamore; false wide (aggregate) rays - hornbeam, alder and hazel. Narrow, but still visible to the naked eye, the rays of the wood of maples, elm species (elm, elm, elm), linden, dogwood and some others. Very narrow rays, which can only sometimes be seen on a strictly radial cut (preferably a split), are characteristic of the wood of all coniferous and many hardwoods (ash, birch, aspen, poplar, willow, pear, mountain ash, etc.). In some breeds, the rays expand when crossing the boundaries of annual layers (beech).

On a radial cut of wood core rays are visible in the form of transverse shiny stripes or spots, colored darker or lighter than the surrounding wood. The width of the strips depends on the height of the rays, and the length depends on the degree of coincidence of the cut plane with the direction of the beam. In some breeds, these stripes form on a radial section. beautiful drawing(sycamore, maple, elm, etc.).

On a tangential cut core rays have a spindle or lenticular shape; their height, depending on the species, varies widely (from 50 mm in oak to fractions of a millimeter in conifers).

In a growing tree, the medullary rays serve mainly to conduct water and nutrients in a horizontal direction and to store reserve nutrients in winter. They perform a specific mechanical function.

The number of core rays in wood is very large. So, in pine and birch, there are more than 3000 rays per 1 cm2 of the surface of the tangential section, and in juniper, in which the core rays are extremely narrow, up to 15,000. Most of the core rays are located in the lower part of the trunk. Higher up the trunk (towards the crown), the number of rays decreases, and in the crown region it slightly increases. The number and size of the medullary rays (width and height) increase in the direction from the core to the cortex. The volume of the core rays depends on the breed, and in the same breed - on the growing conditions. The volume of the rays is sharply different in deciduous (deciduous) and evergreen (coniferous) species. In coniferous wood, the core rays account for an average of 5-8% of the total volume of wood, deciduous - about 15%, i.e. 2.5 - 3 times more. Even larch, shedding needles for the winter, contains almost twice as many rays (by volume) than evergreen conifers (pine, spruce) grown under the same conditions as it.

Core repetitions. This is the name of the brownish or brownish lines, stripes or specks visible on the longitudinal sections of the wood of some hardwoods, located mainly at the boundaries of the annual layers. In their color and structure, they resemble the core. Previously, it was believed that core repetitions (veinlets) arise as a result of damage to the cambium by insects. N. E. Kosichenko, V. V. Korovin believe that these microstructural anomalies can also be caused by other reasons. They are found mainly in the lower part of the trunk of deciduous species (birch, alder, mountain ash, pear, maple, willow, etc.) and occasionally in conifers (fir). The presence of these formations in the wood of some species is so constant (in birch) that they can serve as a diagnostic feature in recognizing the species from wood.

Vessels. On the cross section of the wood of some hardwoods (oak, walnut, etc.), you can see small holes, which are cross sections of vessels. Vessels have the form of tubes of different sizes and are a characteristic element of the structure of hardwood (coniferous species do not have vessels). In a growing tree, water rises through the vessels from the roots to the crown.

Vessels are divided into large, clearly visible to the naked eye, and small, not visible to the naked eye. In a number of breeds, small vessels are collected in groups that can be detected without a microscope. Large vessels are more often concentrated only in the early zone of the annual layer and form a porous ring on the transverse section (for example, in oak), less often large vessels are evenly distributed over the annual layer (for example, in walnut). Collected in groups of small vessels in the presence of large vessels in the early zone, they are located in the late zone, where they are noticeable due to their lighter color. If there are no large vessels, then small vessels in most rocks are scattered throughout the entire layer; however, their number and magnitude somewhat decrease towards the outer boundary of the layer.

The described distribution of vessels makes it possible to divide hardwoods into annular vascular species with a ring of large vessels in the early zone of each annual layer and scattered vascular species, in which the vessels, regardless of their size, are more or less evenly distributed over the annual layer.

The sharp difference between the early and late zones makes the annual rings in ring-vascular rocks clearly visible. At the same time, in scattered-vascular rocks there is no difference between these zones, so the annual layers have a homogeneous structure, and the boundaries between them are poorly visible.

Ring-vascular hardwoods are oak, ash, edible chestnut, elm, elm, elm, velvet tree, pistachio and some others. The majority of hardwoods belong to scattered vascular; among them with large vessels - walnut and persimmon, and with small vessels - birch, aspen, alder, linden, beech, maple, plane tree, poplar, willow, mountain ash, pear, hazel, etc.

Accumulations of small vessels in the late zone form a different pattern. The radial grouping of small vessels in the form of light tongues of flame is characteristic of oak and chestnut; tangential grouping - wavy, sometimes broken lines - for elm, elm, birch bark. A scattered grouping in the form of individual light dots is observed in ash.

On longitudinal sections, vessels, especially large ones, are visible in the form of grooves. Vessels rarely pass strictly vertically in the trunk; on longitudinal sections, the grooves are relatively short, since only part of the vessel enters the section. The diameter of large vessels is 0.2-0.4 mm, small - 0.016 - 0.1 mm. The length of the vessels usually does not exceed 10 cm, but in oak it reaches 3.6 m, and in ash it even reaches 18 m. The volume of vessels in different species varies widely, and for each species it depends on the growing conditions. Along the radius of the trunk, the size of the vessels first increases in the direction from the core to the cortex, reaches a maximum, after which it remains constant or slightly decreases. Along the height of the trunk, the number of vessels and their cross-sectional area increase in the direction from the butt to the top.

Vessels, being weak elements, reduce the strength of felled wood. The presence of vessels explains the increased permeability by liquids and gases of hardwood in the direction along the fibers.

Resin passages. For the wood of a number of coniferous species, the presence of resin passages is characteristic - thin channels filled with resin. They are found in the wood of pine, cedar, larch and spruce; there are no resin passages in the wood of fir, yew and juniper. According to the location in the trunk, vertical and horizontal resin passages are distinguished; the latter pass along the medullary rays and form a common resinous system with vertical passages. Thanks to this system, extraction of resin by tapping is ensured. With the naked eye, only vertical resin ducts can be seen, which are visible on the transverse section mainly in the late zone of the annual layers in the form of whitish dots.

The largest resin passages in cedar - their average diameter is 0.14 mm; the diameter of the resin passages in pine is 0.1 mm, in spruce 0.09 mm, in larch 0.08 mm; the length of the moves is within 10-80 cm.

Pine has the largest number of resin passages, quite a lot of them in cedar, fewer in larch, and even fewer in spruce. In the last two species, resin passages occupy no more than 0.2% of the total volume of wood. However, even in species with large and numerous resin canals, their share in the total volume of wood is less than 1%. Therefore, the passages themselves cannot affect the properties of the wood, but the resin filling them increases the resistance of the wood to decay.

Determination of the species by the macrostructure of wood. Each breed differs in the structure of wood, which determines the originality of its properties. An assessment of the physical, mechanical and technological properties of wood with sufficient accuracy for practice can be made according to reference data, if the breed is known.

To establish the genus, and sometimes the species of a woody plant (species identification), signs characterizing the macrostructure of wood are used. These features include: the presence of a nucleus; the width of the sapwood and the degree of sharpness of the transition from the heartwood to the sapwood; the degree of visibility of the annual layers and their outlines on the cross section; clarity of the boundary between early and late wood of annual layers; the presence, size, color and number of core rays; dimensions, nature of grouping and condition (empty or filled) of vessels in hardwood; the presence, size and number of vertical resin passages in coniferous wood; core repetitions in the wood of some hardwoods.

In addition to these main features, some additional features are taken into account when determining breeds. The need to use them arises in cases where the main features are not clearly expressed. Additional features include gloss, texture, density and hardness.

The wood of some species has a characteristic color, which makes it easier to identify the species. However, the color of the wood may not always serve as a sufficient basis for identifying the species. The fact is that the normal color of wood can change under the influence of external physical and chemical factors, as well as due to fungal infections. The gloss of wood has some diagnostic value.

When cutting anatomical elements, one or another pattern is formed on the surface of longitudinal cuts of wood. A particularly characteristic pattern-texture is formed by core rays. For example, according to the texture of the surface of a tangential section of a beech, this species is unmistakably determined. Sometimes, interrelated properties are involved as an additional feature: the density and hardness of wood.

A rough estimate of the density (weight) and hardness of specimens can be especially useful for identifying diffusely vascular hardwoods, the main features of which are often not pronounced enough.

Original taken from marinagra in Cork: easy, but not easy

Miracle tree and the national symbol of Portugal - that's what the cork oak is!
We are unfair to the cork: it gets from us all the time! "Stupid as a cork", "flew out
like a cork "... The cork causes very unpleasant associations - an ear plug,
traffic jam. An exception is, perhaps, a wine cork. In fact
Cork is a very useful, environmentally friendly and beautiful material.

Serra di Monchichi mountain range in the province of Algarve

To the evergreen cork oak (Quercus suber), supplier of the bark, which is known
we were treated with respect already in antiquity, like a "cork":Pliny the Elder mentioned
in his "Natural History" that in ancient Greece cork trees were dedicated to
Jupiter and were considered a symbol of freedom, only priests were allowed to cut them. "Father
Botany" the ancient Greek philosopher Theophrastus described as a miracle property of cork
oak to restore the bark after it is removed.

Cork grove in the Algarve

It is difficult to say what a greater miracle is the ability of cork oak to regenerate or
unique properties of its bark. The structure of cork can be compared to a honeycomb.
Her cells are like watertight "honeycomb" capsules filled just like
and intermediate spaces, by a gas that differs from atmospheric air those
that does not contain carbon dioxide. Cork is one of the lightest solids, she is strong,
elastic, resilient, can be compressed under pressure and restore its original
form, does not pass heat, sound, liquid, gas. Cork does not sink in water, does not support
burning, does not absorb smells, is steady against friction.

old cork tree

Cork has been used since time immemorial, it was used to make bushings for jugs,
fishing floats, soles, ship tackle. Finest hour traffic jams frowned,
when they were made important discoveries in the field of wine storage: in the 17th century wine
moved from barrels to bottles, and at the turn of the 17th and 18th centuries, bottles began to clog
traffic jams. The honor of this discovery is traditionally attributed to the French monk-
Benedictine Pierre Perignon, who was engaged in the production of champagne.
(Although the name of the monk-winemaker is immortalized in the famous brand of champagne "Dom
Pérignon," he is not the first to think of corking a bottle of wine,
but let's not deviate from the topic).

The only drawback of wine corks was that long-term storage of wine
they dried up. Finally, at the end of the 18th century, pot-bellied wine bottles "lost" so much
that it became possible to store them lying down. A tight-fitting cork, in contact with liquid,
could maintain elasticity for many years, it was impossible for winemakers to wish for better.

cork tree leaves

Extraction and processing of cork is carried out wherever the cork oak grows - in the south
Western Europe and North Africa, but unconditional leadership (more than 50%
production) belongs to Portugal, followed by more than twofold
followed by Spain. Approximately one third of the cork forests of our planet, about 70 million
trees, grows in Portugal, mainly in its southern regions of Alentejo and Algarve. Here
ideal climate for cork oak: moderately rainy autumn, mild winter, hot and
dry summer, suitable soil and altitude (400-500 meters).

Cork oak restoring the bark

The cork oak "sobreiro" is an equally important part of the culture of Portugal and an indispensable
belonging to the local landscape, as in Russia, is a birch. And, just like in Russia - birch,
poets dedicate poems and songs to cork oak, artists depict it in paintings,
as did in 1905 the Portuguese king-painter Carlos the First. In 2011
the Portuguese Parliament, on the initiative of public organizations, unanimously approved
Draft resolution on granting the cork oak the status of the National Tree of Portugal,
along with symbols such as the flag and coat of arms.

To Orol Carlos the First. Cork tree.
Cardboard. pastel, 1905

Cork oaks are very beautiful. Low (up to 20 meters), with wide sprawling
crowns, they seem to grow in breadth. The ocher-red trunks of the freshly liberated
from the bark of trees are adjacent to the darker trunks of oaks, building up the bark.
On each tree, some number is written in white paint: 4, 7, 8 ... What does this mean?
Cork oak allows a person to cut his precious bark only on certain
conditions. Firstly, the tree from which the bark is removed must be at least 25 years old. Yes
and then the first bark of a young oak, which is called "virgin" (cortiça virgem), low
quality, its use is limited. To get a quality bark, you have to wait
second, and better - the third harvest. When will the bare trunk become corked again and
can it be removed? Only through 9-10 years! The inscriptions on tree trunks are
the last digit of the year of removal of the bark: 8 - read "2008", which means that the tree will be able to give back
bark not earlier than 2017.

Grove of cork oaks

tree with fresh bark

Cork is mined only in summer months when the tree is growing
and its tissues are saturated with moisture. According to tradition, the collection of the bark begins on the May new moon.
and finish in mid-August. Many locals take vacations for the main
job to get hired for a summer cork harvest. Cork keeps afloat poor south
Portugal, like a cork belt - an inept swimmer. Worker gets for collecting cork
80-120 euros per day - high pay for agriculture! Collectors are not paid
for production, as it would be logical to assume, but for working hours, so that in pursuit
for profit, people did not show haste and did not harm the trees.Suitable for
processing of trees is prohibited from removing more than 70% of the bark. When the dry hot blows
wind, work stops: the wind can dry up the exposed underbark and
damage the tree.

cork tree cut

peeled bark

Over the centuries, the cork collection technique has not changed: the bark is removed from the trunk and thick branches
special hatchet with a long handle. If the tree answers the first blow of the hatchet
characteristic dull sound - the bark is ripe. First, the bark is cut around and along, and
then they are torn off with the help of the pointed end of the ax handle. The skills of this fine and
responsible work - one wrong move and the tree will be damaged! -
are passed down from father to son.

Cork is ready for processing!

Cork cases for bottles and jars of honey

Cork - absolutely non-waste production. All that's left of strips of bark
after the wine corks have been cut, it is ground into cork crumbs,
which is pressed with an adhesive mixture into blocks, aged and cut into
plates of various lengths, thicknesses and qualities. And what only of these plates is not
do! The range is widest, from construction and industry to
automotive industry and high-tech materials for spacecraft.
Pressed cork is used to make life belts, tropical helmets,
furniture, floor coverings, carpets and rugs, indispensable supports in the household
under hot dishes, bottle caps and all kinds of caps, floats, shoe
soles, insoles, packing material.

Cork postcards

Modern designers are increasingly appreciating not only the lightness and strength of cork, but also its
beauty and decorative expressiveness. From the thinnest, up to 4 mm, layers of cork "fabric"
They make original and by no means cheap things. Showcases of Portuguese shops
fill cork umbrellas, bags, wallets, purses, toilet bags, cosmetic bags, pencil cases,
glasses, hats, caps, shoes, slippers, belts, ties, women's jewelry, covers,
key chains, lampshades, dishes, jewelry boxes, fans, photo frames, postcards.

Showcases with cork wonders

"Save the tree, buy the cork"

In stores with cork miracles, you can often see a poster "Save a tree, buy kork" -
"Save the tree, buy the cork." Cork oak with its ability to regenerate -
ecological dream, fully renewable natural resource. Mining carefully
plug, a person does not cause any damage to nature, and at first glance it may seem
that cork forests in Portugal are not threatened. Here already in the Middle Ages
there were laws to protect cork trees. These days, corruption and illegal
felling trees is punishable by a fine of many thousand and deprivation of the right to use
land for 25 years. Many landowners believe that cork protection laws
trees are even too strict: so as to cut down withered or infected
pest control of the tree requires a government permit. Bye, with true
Portuguese slowness, this permission comes, the sick tree has time
infect neighboring oaks.

Such harsh laws had to be adopted after the 1970s were cut down
500,000 acres of cork oaks to be planted in their place imported from Australia
eucalyptus. It is more profitable to sell wood from fast-growing eucalyptus trees than cork, however
eucalyptus with its soil-draining roots is not at all the tree that this
edge. Ecological damage is huge and, it seems, irreparable: near eucalyptus groves
withered cork oaks can be seen more and more often.

Winemakers dealt another blow to the cork oak. More than 200 years ago, it was the need
in whole wine corks has revived the craft, now the replacement of natural corks
plastic, synthetic ersatz, metal leads to a reduction in production. Although
many winemakers still believe that only a solid cork is worth corking
bottles of vintage wine, prospects for the craft - and with it the cork oak -
disturbing. After all, if the forests lose their economic value, the locals
stop taking care of them and protect them from devastating forest fires. Loss
oaks, in turn, jeopardizes one of the most important ecosystems in Europe, threatens
desertification, disappearance rare species animals and plants, including
including the Iberian lynx, which likes to make a lair in the hollows of old cork
trees.

Not only that: cork oak, especially in the first decades of life, when there is an intense
bark growth, is the record holder among plants for the accumulation of carbon, it absorbs it in five
times more than other trees, and how important this is for reducing greenhouse emissions
gases into the atmosphere, no need to explain. What, however, troubles can arise in
world because of a common wine cork... The motto "Save the tree, buy the cork" can be refined:
"Save cork oak, buy cork." However, perhaps everything is not so bad: in the last
a decade in the circle of winemakers there has been a "cork renaissance", more and more often you can hear
from them that nothing can replace a natural cork!

When uncorking a bottle of wine, pay attention to the cork: how solid, solid,
with manufacturer's logos, or pressed from cork chips, or maybe even
synthetic. And if you come across a real beautiful cork, do not rush to throw it away.
After all, cork is easy, but not at all easy!

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 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 by plantations oak Quercus suber, more than 2 million hectares are occupied! 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 (this is a mixture 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, cork tree bark is unique material given to man by nature.

Question: 2 CLASS: I WILL DO THE BEST AND PUT 2 STARS. TASK #1 READ THE FIRST SENTENCE. GIVE IT A CHARACTERISTIC FOR THE PURPOSE OF THE STATEMENT AND INTONATION. TASKS №2 FIND IN THE TEXT WORDS WITH A SEPARATORY SOFT SIGN. WRITE THEM DIVISION INTO SYLLABLES FOR TRANSFER. TASKS №3 FIND IN THE TEXT WORDS WITH COMBINATIONS ZHI-SHI. THINK 2 MORE WORDS. ASSIGNMENT №4 WHAT DOES THE AUTHOR COMPARE TO THE CORK LAYER OF TREES? TASKS №5 IS IT POSSIBLE TO TRAMP SNOW AROUND TREES?

2 CLASS: I WILL MAKE THE BEST AND PUT 2 STARS. TASK #1 READ THE FIRST SENTENCE. GIVE IT A CHARACTERISTIC FOR THE PURPOSE OF THE STATEMENT AND INTONATION. TASKS №2 FIND IN THE TEXT WORDS WITH A SEPARATORY SOFT SIGN. WRITE THEM DIVISION INTO SYLLABLES FOR TRANSFER. TASKS №3 FIND IN THE TEXT WORDS WITH COMBINATIONS ZHI-SHI. THINK 2 MORE WORDS. ASSIGNMENT №4 WHAT DOES THE AUTHOR COMPARE TO THE CORK LAYER OF TREES? TASKS №5 IS IT POSSIBLE TO TRAMP SNOW AROUND TREES?

Answers:

1. According to the purpose of the statement, it is interrogative, because ends with a question mark. Intonation: non-exclamatory. Because there is no exclamation here. 2. Leaves, trees / 3. From the text: Life, skin, living, fluffy. His own words: Dwelling, tire. 4. Dead layer. 5. No, because best protection for trees, a fluffy snow cover.