Defects of wood
Changes of appearance of wood, infringement of integrity of fabrics and cellular covers, correctness of its structure and the damages of wood lowering its quality and limiting possibility of its application, name defects. Defects of wood of the mechanical origin, arising in it in the course of preparation, transportation, sorting and machining, name defects.
As a rule, defects reduce durability and decorative effect of forest products, therefore a wood rating define with the obligatory account of defects available in it.
Defects of wood (GOST 2140-71) are subdivided into following groups: knots, cracks, defects of the form of a trunk, defects of a structure of wood, chemical colourings, mushroom defeats, damages by insects, foreign impurities and defects, deformations. Each group of defects is subdivided into kinds and versions.
The Majority of defects is formed in a growing tree owing to abnormal conditions of its growth, climatic influences, and also various mechanical damages. The significant amount of defects can be formed in the prepared wood (cracks, damages by insects). Decay arise in growing trees and forest products.
Knots represent the bases of branches, prisoners in trunk wood. Wood of knots differs more dark colour and has independent system of year layers.
Classification of knots. Under the cut form on a surface sortimenta distinguish knots round, oval and oblong. The knots cut in such a manner that the relation bolshego of diameter to the smaller does not exceed two, name round. At oval knots this relation more than two, but no more than four, at oblong more than four.
By position in sortimente knots subdivide on plastevye, kromochnye, rebrovye, face and sshivnye (the knots which longitudinal section leaves simultaneously on two edges of the same party sortimenta).
On a relative positioning distinguish knots scattered, group and branched out. Any knots located odinochno and otstojashchie from each other on length sortimenta on distance, exceeding its width, name scattered. Round, oval and rebrovye the knots which are in quantity two or more on piece sortimenta, which length it is equal to its width, name group. Two oblong knots of one mutovki or one oblong in a combination with oval or rebrovym a knot of the same mutovki, irrespective of presence between them the third, name branched out. More often they meet at coniferous breeds.
On degree of accretion knots subdivide on accrete, partially accrete, not grown together and dropping out not grown together. The knots, which year layers have grown together with surrounding wood throughout not less 3/4 of perimetre of a cut of a knot, name accrete. The knots, which year layers have grown together with surrounding wood on an extent less than 3/4, but more than 1/4 perimetres of a cut of a knot, name partially accrete. The knots, which year layers have no accretion with surrounding wood or have grown together with it throughout no more 1/4 of perimetre of a cut of a knot, name not grown together. Not grown together knots not having accretions with surrounding wood and keeping in her leaky, name dropping out not grown together. To them carry also apertures from the dropped out knots.
On a condition of wood knots share on healthy, light healthy, dark healthy, healthy with the cracks, decayed, rotten and tobacco.
The Knots having wood without signs of soft decay, name healthy. The healthy knots, which wood it is close on colour to surrounding wood, name light healthy. At dark healthy knots wood is plentifully impregnated by pitch, tannic and other substances, it is much more dark some surrounding wood and is frequently non-uniformly painted.
The Healthy knots having one or several cracks, name healthy knots with cracks. Knots with the soft decay occupying no more of 1/3 areas of a cut of a knot, name decayed, and 1/3 of area of a cut of a knot occupying more - rotten. The decayed or rotten knots in which vygnivshaja wood is in full or in part replaced by friable weight of rzhavo-brown or whitish colour, name tobacco.
On an exit on a surface knots happen unilateral (the leaving on one or two adjacent parties sortimenta) and through (leaving on two opposite sides sortimenta).
The Most qualitative bessuchkovaja wood is in the bottom part of a tree trunk (komlevye logs).
Knots - the most widespread and inevitable defect of wood. Knots, especially kromochnye, oblong, sshivnye and group, reduce durability of wood at a stretching along fibres and a bend. At cross-section compression and longitudinal skalyvanii knots raise durability of wood. Tobacco knots specify in presence in decay wood.
Cracks represent ruptures of wood along fibres.
Classification of cracks. Cracks are subdivided on metikovye, frosty, cracks of shrinkage and otlupnye.
Metikovymi cracks name radially directed internal cracks in a kernel or the ripe wood, departing from a core and having the big extent on length sortimenta. Such cracks arise in a growing tree and increase in the cut down wood in the course of it prosyhanija. Metikovye cracks in round forest products happen only at end faces, in piloproduktsii - both at end faces, and on lateral surfaces.
Frosty cracks - radially directed external cracks passing from zaboloni in a kernel and having considerable extent on length sortimenta. Such cracks arise in a growing tree and are accompanied by formation on a trunk of characteristic platens and crests of the expanded wood and a bark. In round forest products frosty cracks happen on a lateral surface in the form of the long and deep cracks surrounded with platens or crests, at end faces - in the form of deep radial cracks to the year layers widened about them, in piloproduktsii - in the form of long radial cracks with the year layers widened and bent about them and dark (at coniferous) the pitched walls.
Otlupnye of a crack - cracks in a kernel or the ripe wood, passing between year layers and having considerable extent on length sortimenta. These cracks arise in a growing tree and increase in the cut down wood in the course of its drying.
Shrinkage Cracks are the radially directed cracks arising in cut down wood under the influence of internal pressure in the course of its drying. From metikovyh and frosty cracks they differ in the smaller extent on length sortimenta (no more than 1 and smaller depth.
The Cracks leaving on a lateral surface sortimenta or on a lateral surface and an end face, name lateral; leaving on plast or on plast and an end face - plastevymi; leaving on an edge or an edge and an end face - kromochnymi, leaving only on end faces sortimenta - face.
Defects of the form of a trunk
To defects of the form of a trunk carry sbezhistost, zakomelistost, outgrowths and curvature.
Sbezhistost represents gradual reduction of a thickness of round forest products or width of not edging saw-timbers on all their extent, exceeding size normal sbega, equal 1 sm on 1 m of length sortimenta. Sbezhistost increases quantity of a waste at a cutting of round forest products and raskroe piloproduktsii.
Zakomelistost is a sharp increase in diameter komlevoj parts of round forest products or width not edging piloproduktsii when diameter (or the width) komlevogo an end face not less than in 1.2 times exceeds diameter (or width) sortimenta, 1 m measured on distance from this end face. Zakomelistost distinguish roundish (sortiment has the roundish form of cross-section section) and ridge (the cross-section section sortimenta has zvezdchato-lopastnuju the form).
Zakomelistost complicates application of round forest products to destination, increases quantity of a waste at their cutting and raskroe piloproduktsii, causes occurrence in piloproduktsii and an interline interval of a radial inclination of fibres.
Outgrowths - a sharp local thickening of a trunk of the various form and the sizes, have svilevatuju wood. Outgrowths meet on all breeds of wood, more often on the deciduous. Outgrowth presence complicates application of round forest products to destination and complicates their processing. Wood of outgrowths owing to pereputannosti fibres, presence of curls and eyes differs very beautiful structure, therefore is highly appreciated in manufacture of furniture and art products where it apply mainly in the form of a facing interline interval.
Curvature - a curvature of a longitudinal axis sortimenta. It happens simple and difficult. Simple curvature is characterised only by one bend sortimenta, and difficult - several bends sortimenta.
Defects of a structure of wood
Defects of a structure of wood concern: an inclination of fibres, kren, traction wood, svilevatost, a curl, eyes, a pitch pocket, a core, a double core, the stepson, suhobokost, prorost, a cancer, zasmolok, a false kernel, pjatnistost, internal zabolon, a water layer.
The Inclination of fibres is neparallelnost fibres of wood of a longitudinal axis sortimenta. The inclination of fibres can be tangentalnyj and radial.
Tangentalnyj find out an inclination of fibres in round forest products on a lateral surface and tangentalnyh surfaces piloproduktsii and an interline interval on neparallelnosti serdtsevinnyh beams, pitch courses, cracks and strips of mushroom defeats of a longitudinal axis sortimenta.
The Radial inclination of fibres find out in piloproduktsii and an interline interval on radial surfaces on neparallelnosti year layers of a longitudinal axis sortimenta, and on tangentalnyh surfaces - on drawing vyklinivanija and cuttings of year layers. The radial inclination of fibres meets in piloproduktsii and an interline interval, made of the round forest products having defects of the form of a trunk (sbezhistost, zakomelistost, curvature).
The Inclination of fibres raises durability of wood at splitting, complicates its machining, lowers ability to a bend, and also durability piloproduktsii and an interline interval at a stretching along fibres and a bend. The tangentalnyj inclination of fibres in saw-timbers leads to the raised longitudinal shrinkage and korobleniju.
Kren - local change of a structure of wood of coniferous breeds in the compressed zone of trunks and the branches, shown in the form of seeming sharp increase in width of late wood of year layers. At end faces of forest products kren it is observed in the form of bow-shaped, is more rare than ring sites of phaeochrous wood; on a lateral surface piloproduktsii and an interline interval - in the form of the same colour of strips.
Kren is formed mainly in wood of a fur-tree and is peculiar bent and naklonno to standing trunks, and also all branches.
Distinguish kren local and continuous. Local kren looks like the narrow bow-shaped sites grasping one or several year layers. Continuous kren grasps a considerable part of the area of cross-section section of a trunk, sometimes half and it is more. It is located on one party from a core.
Kren raises hardness of wood and its durability at compression and a static bend; reduces impact strength at a bend and durability at a stretching; increases shrinkage along fibres, causing it rastreskivanie and longitudinal koroblenie piloproduktsii; reduces water absorption of wood and that complicates it propityvanie, and also worsens appearance of wood.
Traction wood - local change of a structure of wood of deciduous breeds in the stretched zone of trunks and the branches, shown in sharp increase in width of year layers in the stretched zone, their more light colouring and occurrence of an original serebristo-matte reflexion. Forest products with traction wood on cross-section and longitudinal raspilah have a fluffy-velvety surface. This defect is observed at end faces in the form of bow-shaped sites, on radial surfaces piloproduktsii and in an interline interval from wood with distinct year layers (an oak, an ash-tree) - in the form of narrow strips-tjazhej. In forest products with poorly expressed year layers (a maple, a birch) to define traction wood very difficultly.
This defect raises durability of wood at a stretching along fibres and impact strength at a bend, reduces durability at compression along fibres and a static bend, raises shrinkage in all directions, especially along fibres that promotes occurrence koroblenija and cracks, complicates processing, leading to formation of hairiness and mshistosti surfaces.
Svilevatost - a twisting or chaotic arrangement of fibres of wood. It meets on all tree species, more often on deciduous, and mainly on forest products from komlevoj trunk parts. Svilevatost happens wavy and confused. Wavy svilevatost it is characterised more or less correct arrangement of fibres of wood, confused - a chaotic arrangement of fibres of wood. Svilevatost reduces durability of wood at a stretching, compression and a bend, raises durability of wood at splitting and skalyvanii along fibres, complicates milling and tesku wood.
The Curl - the local curvature of year layers caused by influence of knots or prorostej; meets in the form of partially cut, skobkoobrazno the bent concentric contours formed by bent year layers.
Distinguish a curl unilateral and through. The unilateral curl leaves on one or two adjacent surfaces sortimenta, and through - on two opposite sides sortimenta.
The Curl, especially through, reduces durability of wood at compression and a stretching along fibres and at a static bend, and also impact strength at a bend. Durability of wood considerably decreases at an arrangement of curls in the stretched zone of dangerous section.
Eyes are traces of the sleeping kidneys which have not developed in runaway. Diameter of eyes does not exceed 5 mm.
Depending on an arrangement eyes happen scattered and group. The scattered eyes settle down odinochno and will defend one from another on distance more than 10 mm. Group eyes are concentrated in number of three and more and will defend one from another on distance no more than 10 mm.
Depending on colour distinguish eyes light and dark. Wood of light eyes is close to colour of surrounding wood, and dark - is much more dark than it.
In small sortimentah the eyes which are in dangerous section, reduce their durability at a static bend and impact strength at a bend.
The Pitch pocket represents a cavity in the year layer, filled with pitch. It is observed on tangentalnyh surfaces in the form of oval flat deepenings, on radial surfaces - in the form of narrow longitudinal cracks, at end faces - in the form of short bow-shaped cavities. The pitch pocket meets in wood of coniferous breeds, more often at a fur-tree.
Distinguish a pitch pocket unilateral and through. The unilateral pitch pocket leaves on one or two adjacent, and through - on two opposite sides sortimenta.
In fine details pitch pockets reduce durability of wood. Pitch following from pitch pockets spoils a surface of products and interferes with their obverse furnish and pasting.
The Core - the narrow central part of a trunk consisting of a friable fabric; it is characterised brown or more light, than at surrounding wood, colour. At end faces sortimenta it is observed in the form of small (to 5 mm) a speck of the various form, on radial surfaces - in the form of a narrow direct strip. Sortimenty which have this defect, are subject rastreskivaniju.
The Double core is characterised by presence in sortimente two cores. In round forest products it is observed at the top end faces in the form of two cores with the independent systems of year layers surrounded from periphery with one general system.
The Double core complicates processing of wood and increases quantity of a waste. Sortimenty with a double core easily rastreskivajutsja.
The Stepson - lagged behind in growth or the died off second top which is passing through sortiment at an acute angle to its longitudinal axis on a considerable extent.
This defect is observed on a lateral surface of round forest products in the form of strongly extended oval at which one diameter exceeds another more than in 4 times, in piloproduktsii and an interline interval - in the form of the same oval or the extended strip.
The Stepson breaks uniformity of a structure of wood, and in piloproduktsii sometimes and its integrity, reduces mechanical properties of wood, especially at a bend and a stretching.
Suhobokost is the site which has become lifeless in a growing tree of a surface of a trunk. It arises in places of damages (a burn, a bruise, zarub), is usually deprived a bark, is extended on length of a trunk, is deepened in relation to its other surface and along the edges has flows in the form of wood and bark platens. Suhobokost it is often accompanied by development in adjoining wood zasmolka, zabolonnyh mushroom colourings, mushroom jadrovyh stains and strips jadrovoj decay. This defect breaks correctness of the form of round forest products and integrity of wood, causes a local curvature of year layers.
Prorost - the site which has acquired wood of a surface of a trunk with the become lifeless fabrics and a radial crack departing from it. It arises in a growing tree at zarastanii the damages put to it and is frequently accompanied by development in adjoining wood zasmolka, mushroom jadrovyh stains and strips jadrovoj decay.
Depending on an arrangement in sortimente distinguish following versions prorosti: opened, unilateral opened, through opened, closed, accrete.
Opened prorost leaves on a lateral surface sortimenta or on a lateral surface and an end face; unilateral opened prorost - on one or two adjacent parties sortimenta; through opened prorost - on two opposite lateral faces sortimenta; closed prorost - on an end face also has no exit on its lateral surface. Accrete prorost represents a trace from closed prorosti in the form of a seam svilevatoj wood on an interline interval surface.
Depending on colour prorost happens light and dark. At light prorosti wood on colour is close to surrounding and does not contain bark inclusions, and at dark wood is much more dark surrounding or contains bark inclusions.
Prorost breaks integrity of wood and is accompanied by a curvature of adjoining year layers.
The Cancer is the wound which has arisen on a surface of a trunk of the growing tree as a result of activity of parasitic mushrooms and bacteria. It can be opened and closed. At an open cancer a wound not grown, with a flat or profound bottom, step edges and flows on periphery, at closed - an overgrown wound with abnormal thickenings of fabrics of a bark and wood near the amazed places.
The Cancer changes the form round sortimentov and a wood structure; at coniferous breeds it is accompanied strong smolotecheniem and zasmoleniem wood; complicates use sortimentov to destination and their machining.
Zasmolok - the site of wood plentifully impregnated with pitch. In round forest products it is found out on presence of wounds and a pitch congestion, in piloproduktsii and an interline interval the tarred sites are much more dark some normal wood surrounding them. This defect meets only in wood of coniferous breeds.
Zasmolok essentially does not influence mechanical properties of wood, however considerably reduces impact strength at a bend, reduces water penetration of wood, complicates obverse furnish (colouring, varnishing) and wood pasting.
The False kernel represents dark colouring of different shades, intensity and uniformity of an internal part of a trunk without fall of hardness of the wood, arising in growing trees of some breeds (a birch, a beech, an alder, a maple, etc.). Under the form on a trunk cross-section the false kernel can be round, zvezdchatym or lopastnym, sometimes happens eccentric. It has dark-brown or red-brown colouring, sometimes with a lilac, violet or dark green shade. From zaboloni the false kernel is separated dark (less often light) by a border. On longitudinal sections looks like a wide strip of one or several colours.
This defect meets only in wood of deciduous breeds. It spoils appearance of wood, differs the bad permeability lowered by durability at a stretching along fibres and the big fragility. At a birch the false kernel is easy rastreskivaetsja. To rotting the false kernel surpasses In firmness zabolon.
Pjatnistost represents local colouring zaboloni in the form of stains and strips without decrease in hardness of the wood, close on colour to kernel colouring. Defect arises in growing trees, happens several kinds: tangentalnaja, radial pjatnistost, the proveins, the scattered proveins, group proveins, traces from proveins.
Tangentalnaja pjatnistost - stains on the face cuts, extended in tangentalnom a direction on year layers; on longitudinal sections it is observed in the form of numerous narrow and long strips.
Radial pjatnistost - stains on the face cuts, extended in a radial direction lengthways serdtsevinnyh beams; on longitudinal sections it is observed in the form of narrow vyklinivajushchihsja by both ends of longitudinal strips. Radial pjatnistost it is formed as a result of influence of mushrooms or insects.
Proveins - stains in the form of the thin zheltovato-brown strips of a friable fabric located on border of year layers. They represent overgrown traces of damages kambialnogo a layer of a tree larvae of some kinds of flies.
The Scattered proveins are located odinochno, and group - skuchenno, in the form of intertwining strips.
Traces from proveins - whitish or darkish strips on the surfaces of the interline interval which has arisen from lying down under it on depth no more 1 mm of proveins.
Pjatnistost does not influence mechanical properties of wood, in an interline interval in places of a congestion of large stains radial pjatnistosti sometimes occurs rastreskivanie wood.
Internal zabolon - group of the adjacent year layers located in a zone of a kernel, colouring and which properties are close to colouring and properties zaboloni. This defect happens at end faces in the form of one or several rings of different width and more light, than surrounding wood; on lateral surfaces - in the form of strips of the same colour. Meets in wood of an oak, an ash-tree and other deciduous breeds.
On mechanical properties internal zabolon it is not cast from a kernel, possesses the raised permeability for liquids and the lowered firmness to rotting.
The Water layer are sites of a kernel or ripe wood of the abnormal dark colouring, appearing in a growing tree as a result of sharp increase in their humidity. This defect happens at end faces svezhesrublennoj wood in the form of wet, dark, and in the winter frozen, steklovidnyh stains of the various form and size, and on longitudinal sections - in the form of strips. At wood drying dark colouring almost disappears, but on a surface appear small treshchinki. The water layer meets at all trees, more often at coniferous, mainly in forest products from komlevoj trunk parts.
The Water layer is at the bottom rastreskivanija, besides, it reduces impact strength at a bend and is quite often accompanied by decay.
Chemical colourings name the abnormal colourings arising in cut down wood as a result of chemical and biological processes. In most cases chemical colourings are a consequence of oxidation of tannins containing in wood. Chemical colourings are uniform on colour and are located usually in wood blankets on depth 1... 5 mm. At drying of wood they frequently fade.
Chemical colourings concern: a procudgel, tannic begin to flow also yellowness.
The Procudgel - krasnovato-brown or brown colouring of subcrustal layers of floatable wood of those breeds, which bark is rich with tannins (a fur-tree, an oak, a willow).
Tannic begin to flow - brown stains in a kind potekov on a surface sortimentov those breeds which wood is rich with tannins.
Yellowness - light yellow colouring zaboloni floatable wood of the coniferous breeds, arising at intensive drying.
Chemical colourings do not influence physicomechanical properties of wood; at intensive colouring worsen appearance of facing materials.
Wood changes the colour and decays at development in it of mushrooms. Mushrooms concern the lowest plants, breed disputes, that is have no chlorophyll and cannot form necessary nutrients, and receive them from live plants or from the dead (cut down) wood. Disputes, having got to wood, sprout and form floccuses (the most thin threads).
Mushrooms Amazing wood are subdivided on derevookrashivajushchie and derevorazrushajushchie.
Development derevorazrushajushchih mushrooms occurs at temperature from 2 to 350С, at humidity of wood from 20%. At high humidity when wood is in water, mushrooms do not develop. Optimum for development of mushrooms temperature from 15 to 250С and humidity of wood from 30 to 60%. Destructive action of mushrooms in the conditions of variable humidity and variable temperature is especially great. It speaks that elements of socle overlapping, obvjazki on a socle, wreaths (bottom) bruschatogo buildings, podokonnye boards, columns on border of soil with atmosphere, etc. most often rot
At temperature more low 20С and above 350С development of mushrooms is slowed down and even can stop absolutely, but mushrooms thus do not perish; with approach of favorable conditions their development renews. At temperature from 600С and above the majority of mushrooms perishes.
Mushroom jadrovye stains and strips - sites of abnormal colouring of a kernel (the present, false and ripe wood) without fall of hardness the wood arising in the growing tree under influence derevorazrushajushchih of mushrooms (the first stage). They are visible at end faces in the form of stains of various size and the form (lunok, rings and the concentrated zone of continuous defeat of the central part of a trunk, sometimes with an exit on periphery) brown, reddish, grey and grey-violet colours, and on longitudinal sections - in the form of the extended stains and strips of the same colours. These defects essentially do not influence quality of wood, reduce durability at shock loadings some, spoil appearance and raise water penetration of wood.
Jadrovaja decay - sites of abnormal colouring of a kernel (the present, false and ripe wood) with the lowered hardness the wood arising in the growing tree under influence derevorazrushajushchih of mushrooms (the second stage). It is observed at end faces in the form of stains of various size and the form - lunok, rings or the concentrated zone of continuous defeat of the central part of a trunk, sometimes with an exit on periphery on longitudinal sections in the form of the extended stains and strips.
Jadrovaja decay on colour and character of destruction happens motley sitovaja, brown treshchinovataja, white fibrous.
Motley sitovaja jadrovaja decay develops basically in a growing tree and is characterised by the motley colouring caused by presence on brown, by a krasnovato-drill or a grey-violet background of amazed wood of numerous small white both yellowish specks, and cellular or fibrous structure. The amazed wood long keeps integrity, at strong destruction becomes soft and is easily split. Motley sitovaja decay is characteristic for coniferous and deciduous breeds, in the cut down wood development of motley decay stops.
Brown treshchinovataja jadrovaja decay has brown or grey colour of various shades and treshchinovatuju prizmaticheskuju structure. Easily breaks up to parts and it is pounded in a powder. Meets on coniferous and deciduous breeds.
White fibrous jadrovaja decay differs light yellow or nearly so white colour and fibrous structure. The amazed wood often gets the motley colouring reminding drawing of marble in which light sites are limited from more dark by thin black twisting lines. At strong destruction wood becomes soft, is easily split on fibres and crumbles.
Jadrovaja decay essentially influences mechanical properties of wood. Depending on the sizes of defeat of wood decay the rating decreases up to its full unfitness.
The Mould represents a mycelium and fructification plesnevyh mushrooms on the surfaces of wood appearing more often on crude zaboloni at storage of forest products.
This defect represents separate stains or a continuous touch of green, blue-green, blue, black, pink or other colour.
The mould does not influence mechanical properties of wood, but worsens appearance, besides, at manufacturing from container wood, it is capable to pass to a foodstuff and products and is capable to destroy animal glues. After drying it will easily be swept away, leaving sometimes on a wood surface rather dirty or colour stains.
Zabolonnye mushroom colourings represent abnormal colouring zaboloni without fall of its hardness. This defect arises in the cut down wood under influence derevookrashivajushchih mushrooms and extends deep into wood from end faces and lateral surfaces. At end faces zabolonnye mushroom colourings are visible in the form of stains of different size and the form and continuous defeat zaboloni, on lateral surfaces - in the form of the extended stains, strips and continuous defeat zaboloni. This defect is peculiar to all tree species, but to the greatest degree coniferous.
Zabolonnye mushroom colourings are divided:
On colour - blue, that is grey colouring zaboloni with bluish or greenish shades; colour zabolonnye stains - colouring zaboloni in orange, yellow. Pink, light-violet and brown colours;
On intensity of colour - light (pale tones) and dark (wood masking a structure);
On depth pronikanija in wood - superficial (than 2 mm get on depth no more), deep (than 2 mm get on depth more) and podslojnye (settle down on some distance from a surface sortimenta).
Zabolonnye mushroom colourings do not influence mechanical properties of wood (deep blue reduces resistance of wood to shock loadings a little), but worsen its appearance and raise water penetration. The mushrooms painting zabolon. Can destroy glue and paint and varnish coverings.
Poburenie - brown colouring of wood zaboloni different shades, various intensity and uniformity. Appears in the cut down wood as a result of development of biochemical processes with participation of mushrooms or without them and causes some decrease in durability of wood. This defect precedes zabolonnoj to decay.
Poburenie extends deep into wood from end faces and lateral surfaces. It is observed only on fresh cuts of wood: at end faces in the form of stains of various size and the form and continuous defeat zaboloni, on lateral surfaces in the form of the extended stains, strips and continuous defeat zaboloni. Most often poburenie amazes wood of deciduous breeds, especially birches, a beech and an alder. poburenie distinguish face and lateral.
Poburenie changes durability at static loadings and hardness of wood a little, but reduces impact strength at a bend, worsens appearance of wood, and at a beech reduces water penetration.
Zabolonnaja decay - abnormal sites on colouring zaboloni without fall or with fall of hardness of wood. This defect arises in suhostojnoj, valezhnoj and the cut down wood under influence derevorazrushajushchih mushrooms. Zabolonnaja decay extends deep into wood from end faces and lateral surfaces. At end faces it is observed in the form of stains of different size and the form and continuous defeat zaboloni, on longitudinal sections - in the form of the extended stains, strips and continuous defeat zaboloni.
Zabolonnaja decay is inherent in all tree species. At coniferous the amazed wood gets zheltovato - or rozovato-brown colouring, at deciduous - motley, reminding marble drawing. Develops at long and wrong storage, more often in round forest products. At deciduous breeds zabolonnaja decay usually follows for pobureniem and can pass in a kernel. Distinguish zabolonnuju decay firm and soft.
Firm zabolonnaja decay reduces durability of wood at a static bend on 22%, at compression along fibres - on 20... 25%. Soft zabolonnaja decay sharply reduces mechanical properties of wood.
External mouldering decay represents sites of abnormal colouring, structure and hardness the wood arising in forest products at their long storage under influence derevorazrushajushchih of mushrooms. This defect is observed mainly in external both zabolonnoj, and jadrovoj parts sortimenta, covers it on all cross-section section or only by a part and extends deep into, quite often develops on cracks.
External mouldering decay is characterised by brown colour of various shades and treshchinovatoj prizmaticheskoj structure. The wood amazed with mouldering decay easily breaks up to parts and is pounded in a powder. On a surface of the amazed wood are often observed tjazhi, myceliums and fruit bodies.
External mouldering decay sharply reduces mechanical properties of wood, destruction process can proceed not only in not dried, but also in rather seasoned wood. The amazed wood - a dangerous source of a mushroom infection for wooden designs and constructions.
Damages of wood by insects
Insects damage mainly neoradical svezhesrublennye materials. Some of them make courses only in a bark, and many go deep into wood. Set of courses and the apertures done in wood by insects and their larvae, name a wormhole. The wormhole is observed on a surface of forest products in the form of round and oval apertures or in the form of grooves and flutes. Depending on depth of penetration the wormhole happens superficial, superficial, deep and through.
The Superficial wormhole gets into wood on depth to 3 mm, superficial - on depth to 15 mm in round forest products and no more than 5 mm in piloproduktsii, deep - on depth of 15 mm and more in round forest products and more than 5 mm in piloproduktsii. The through wormhole leaves on two the parties sortimenta are opposite.
On the size of apertures a wormhole subdivide on medium-sized and large. The medium-sized wormhole is characterised by apertures with a diameter to 3 mm, and large - with a diameter more than 3 mm. The superficial wormhole does not influence mechanical properties of wood. Superficial and deep wormholes break integrity of wood and reduce its mechanical properties.
Foreign impurities and defects
This group of defects concern: foreign impurities, mechanical damages, obuglennost, skos has spent on drink, obzol, zakorina and defects of processing by cutting.
Foreign impurities represent foreign matters of not wood origin present at wood (metal splinters, nails, a wire, stones, sand). Local swellings and folds of a bark of wood, sometimes local deformation of a lateral surface and presence in it of apertures, in piloproduktsii - change of colour of surrounding wood can be an external sign of defect in round forest products.
Mechanical damages - damages of wood by the tool and mechanisms at preparation, transportation, sorting and processing. Mechanical damages concern obdir barks, zarub and has washed down, karra, otshchep, skol and having dug, bagornye nakoly.
Obdir of a bark - a site of a surface of the neoradical round forest product, deprived of a bark.
Zarub also has washed down - local damages of a surface of forest product by an axe, a saw, a cable lebedki, mechanisms and other tool.
Karra - the damage of a trunk received at podsochke. Wood in area karry is strongly pitched.
Otshchep, skol and having dug - departing from an end face of forest products a through lateral crack or loss of a part of the wood adjoining an end face. In process of removal from an end face the thickness otshchepivshejsja or the broken away part of forest product decreases.
Bagornye nakoly turn out owing to damage of a surface of round forest products by a hook at an alloy or sorting. Are observed in round forest products and piloproduktsii in the form of superficial (1.5... 2 sm), and in an interline interval - through apertures. Bagornye nakoly often happen are surrounded by stains of chemical colourings.
Mechanical damages influence quality of wood. Obdir barks are reduced by firmness svezhezagotovlennyh neoradical round forest products to mushroom defeats and rastreskivaniju. Zarub, has washed down, karra, otshchep, skol and having dug complicate use of forest products to destination, and at the big sizes reduce their mechanical durability and integrity, increase quantity of a waste at sawing up both lushchenii round forest products and raskroe piloproduktsii. Otshchep and skol in an interline interval reduce its actual width, and bagornye nakoly worsen appearance of wood.
Obuglennost - the burnt and charred sites of a surface of the forest products, the wood which have appeared as a result of damage by fire (at forest fires, burning porubochnyh the rests). Obuglennost it is accompanied by loss of a part of wood and change of the form of a lateral surface of forest products, can complicate use of forest products to destination, increases quantity of a waste at sawing up both lushchenii round forest products and raskroe piloproduktsii.
Skos has spent on drink - the defect received in the course of preparation of forest products. Represents neperpendikuljarnost an end face of a longitudinal axis sortimenta. Reduces actual length sortimentov. Complicates their use to destination, increases quantity of a waste at their cross-section raskroe.
Obzol - a site of the lateral surface which has remained on edging pilomateriale. Distinguish obzol stupid and sharp. Stupid obzol occupies a part of width of an edge, and sharp - all the width long edges.
Obzol reduces actual width of the parties sortimenta, complicates use of saw-timbers to destination and increases quantity of a waste at raskroe.
Zakorina - a site of the bark which have remained on a surface of an interline interval. Arises at development of an interline interval from churakov with curvature, ridge zakomelistostju and other local roughnesses of a surface of a trunk. Zakorina increases quantity of a waste of an interline interval, often drops out, leaving in an interline interval flat deepenings and through apertures.
Defects of processing by cutting - surface damages sortimenta, wood arising at processing by the cutting tool. Distinguish following defects of processing of wood cutting: risks, a sinuosity, hairiness, mshistost, ripples of an interline interval, the tease and vyshcherbiny, a fringe, a burn.
Risks - the scars left on a surface of wood by working bodies of the cutting tool (teeths of saws, lushchilnymi knifes and so forth).
The Sinuosity turns out at nonplanar to a prosaw.
Hairiness is characterised by presence on a surface of materials of separated fibres of wood often located short.
Mshistost - often located on a surface of forest products bunches of short separated fibres and small particles of wood.
Interline interval Ripples - often located on an interline interval surface the small deepenings focused along fibres of wood.
Teases and vyshcherbiny - partially separated and raised over a surface sortimentov sites of wood with zatsepistymi edges and deepenings adjoining them with a rough ridge bottom. On places completely broken away zadirov there are one vyshcherbiny. Teases and vyshcherbiny are always focused along fibres and accompany knots, an inclination of fibres, svilevatosti and to curls.
The Fringe represents a continuous or faltering tape of bunches of short separated fibres and a wood part on edges of saw-timbers.
The Burn - dimness and partial obuglivanie surfaces sortimentov from influence of the heats arising at the raised friction of the cutting tool about wood.
Defect turns out at using the stupid or badly dissolved tool.
Wood deformations concern pokoroblennost following versions: longitudinal on plasti, simple longitudinal on plasti, difficult longitudinal on plasti, longitudinal on an edge, cross-section and krylovatost.
Pokoroblennost represents a curvature piloproduktsii at vypilovke, drying or storage.
Longitudinal pokoroblennost on plasti - a curvature piloproduktsii on length planes, perpendicular plasti.
Simple longitudinal pokoroblennost on plasti - longitudinal pokoroblennost on plasti, characterised only one bend.
Difficult longitudinal pokoroblennost on plasti - longitudinal pokoroblennost on plasti, characterised by several bends.
Longitudinal pokoroblennost on an edge - a curvature piloproduktsii on length a plane parallel plasti.
Cross-section pokoroblennost - a curvature piloproduktsii on width.
Krylovatost - a spiral curvature piloproduktsii on length.
Pokoroblennost changes the form piloproduktsii, complicates its use to destination, processing and open. The size pokoroblennosti changes at drying and wood humidifying.
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