The conditions in which a tree grows and develops affect not only the texture of its wood, but also lead to various deviations from the structure and development of the trunk. This, in turn, can cause the presence of various defects that impose restrictions on the scope of wood use..
Such deviations include various curvature of the trunk, growths, knots and forks along its length, causing disturbances in the texture itself, changing its color and affecting the mechanical strength of wood.
Cracks appear in wood as it grows. Their formation is influenced by natural factors and internal stresses that have arisen in the trunk. Distinguish between frost, shallow and metic cracks.
Frosty cracks appear as a result of the expansion of internal moisture during severe frosts. The result is through cracks directed radially.
Internal stresses arising in the trunk lead to the appearance awesome (separation of annual layers from each other) and metik (going along the trunk from the butt to the top) cracks. In addition, when wood is dried, cracks may appear as a result of shrinkage..
Knots appear in the place of sprouting of branches and significantly reduce the value of wood. In places of knots, the mechanical strength of wood decreases, since after drying, the knot loses its connection with the base and weakens the structure. In addition, knots affect the appearance of the wood grain intended for a transparent finish..
Oblique (grain tilt) represents the various deviations of the grain direction from the longitudinal axis of the tree. Wood with such a defect does not tolerate lateral load well. The varieties of oblique layer include curl (wavy placement of fibers) and curl (local curvature of annual layers).
Prophecy – a defect in a section of a tree resulting from mechanical damage to the fiber. Such a piece of wood spoils the appearance and makes it difficult to finish. Often in this place there are mushroom spots and tar..
Fungal lesions wood arise as a result of the influence of putrefactive processes on it. As a result, the mechanical properties of wood and its color tones change..
What are some common flaws found in lumber, and how can they affect the quality and structural integrity of the wood?