Defects of wood are called trunk shape defects (outgrowths, escapism, knuckles, etc.), natural heterogeneity of the structure of wood (knots, core, stubble, vomiting, etc.), violations of the integrity of its tissues for various reasons (cracks, resin pockets, wormholes, rot, etc.). etc.), dyes of biological chemical origin (blueness, veneer, etc.), foreign inclusions, mechanical damage and processing defects that reduce the quality of wood and limit its use.
In some cases of use of wood heterogeneity of its structure, called a defect, is considered to be the dignity of wood. For example, outgrowths with a beautiful texture are valuable raw materials for artistic crafts.
Blue and similar vices begin to be perceived as a sign of natural wood in a shortage of wood and the widespread use of plastics. Knots are considered the main variety-forming vices, their presence limits the standards and specifications for certain products, however, healthy fused knots are indispensable in country and renaissance styles.
A knot is the base of a branch enclosed to the wood of the trunk. According to the degree of overgrowth, round timber distinguishes between open knots (appearing on the side surface of the assortment) and overgrown knots (found on bloating and other signs of overgrowth on the side surface of the assortment).
Open knots are divided into:
- By the shape of the cut on the surface of the assortment – round, oval, oblong.
- In terms of position in the assortment – on the formation, rib, edge, end.
- By mutual arrangement – on scattered, group, branched.
- In terms of the degree of adhesion with the surrounding wood – on fused, partially fused, not fused, falling out.
- As for wood – healthy (wood without rotten), light, dark, healthy with cracks, rotten, rotten, tobacco.
- At the exit to the surface – on unilateral, through.
The main types of bitches
- round,
- oval,
- It’s elongated,
- Plast,
- the edge,
- ribbed,
- stitches,
- group,
- branched out.
Cracks are disorders of wood integrity caused by internal tension. They can be separated:
- the type of shrinkage cracks, shrinkage cracks, frosty cracks.
- in terms of position in the assortment – on the side, plastic, edge, end.in depth – shallow, deep, transversal
- in width, closed and apart.
Defects of the wood structure
- tangential fiber inclination,
- the root,
- vomit,
- a curl,
- eyes,
- a false core.
Chemical coloring – abnormally colored areas in felled wood, which appear as a result of chemical and biochemical processes, in most cases connected with oxidation of tannins.
Biological damage – wormholes – passages and holes made in wood by insects, mainly by their larvae. Surface wormhole does not affect mechanical properties of wood. Shallow and deep wormholes disturb wood integrity.