In svezhesrublennom a poplar the moisture makes from 60 to 80% on weight, in ready wood for joiner's works it decreases almost in 10 times. .
Thus as humidity understand an organic endocellular liquid. Its drying under natural conditions, on air occurs within two and more years. In steam sushilnyh chambers of furniture factories humidity lead up to admissible limits (8 - 12%) within two-three days, and electrodrying occupies all some hours. But if a dry board to leave for long time in the rain, it will become wet, becomes heavy, it will be difficult for sawing, it is almost impossible to plane. This introduced moisture which is not an organic part of wood, quickly evaporates. The board brought in a warm aired premise, will dry up without artificial heating of all in some hours, its natural humidity what it was to a rain will be restored. .
It is easy to screw a screw in a lime or fur-tree board, and the nail is hardly hammered into the beechen even. The joiner rather easily removes one for another a thin shaving from an edge of a board from prjamoslojnoj wood of a pine, a birch, a maple, and wood of the Caucasian box and a palm tree hardly gives in to cutting, it on density and hardness does not concede to some metals.
On metalcutting machine tools the turner or the milling-machine operator can work all change with one tool, without sharpening cutters, mills. On derevoobrabatyvajushchih machine tools knifes change and sharpen at times on two times for change. The reason is covered in heterogeneity of processed wood.
Physical and mechanical properties of wood of various breeds cause tree application in land and underwater building, furniture manufacture and in many other branches of a national economy. The oak and a larch are widely used in underwater constructions. In water wood not only does not rot, but with decades types durability. And birch logs are applied never to building zhi lyh houses by them in the open air, even protected from a rain and snow, quickly rot, birch wood - a good nutrient medium for bugs-koroedov. .
Look at a cross-section cut of a tree, well it is simple on a log end face. You will see kontsentricheski located on a circle of a trunk of the ring, different one from another in the thickness, intensity of colouring, colour. These are the year wood rings, everyone - year of a life of a tree. neodinakovy rings and on a thickness, the tree grows in favorable weather conditions more intensively means, faster, and the gain is more, a ring more thickly. It is less than rings - at coniferous breeds.
Each of layers is non-uniform and on density. In the spring and in the summer when it is a lot of light, heat and a moisture, the tree grows more intensively, in the autumn growth is slowed down, cages become more small, the density of an annual ring increases. .
In the centre of a cross-section cut there is a dark roundish stain (fig. 1), is a trunk core, the beginning of occurrence of a life of a tree, it and grows old earlier, wood rotting, hollow formation usually begins with a core. Further there are year layers increasing in diameter. The extreme external layer is a bark, further to the centre the layer kambija, nursery of live cages is located. In the spring when the plant clears up from winter rest, cages start to share, forming a new annual ring. What it will be, depends in many respects on character of summer - rainy or dry, cool or hot.
Popererechnyj a tree trunk cut:
1 - a kernel; 2 - godovyj rings; 3 - kamby; 4 - a bark
If to cut a trunk not across, and lengthways, become, are visible various on width, colour and provein density - serdtsevinnye the beams penetrating year layers. On them from kambija there are on all trunk to branches and leaves the nutrients arriving on roots from soil. The drawing opening on a surface of wood after cutting of fibres of year rings and nutritious serdtsevinnyh of beams, name a wood structure. The more variously this drawing on a configuration and colour shades, the more valuably wood as a finishing material in joiner's manufacture. .
The Joiner interests, in what year a little, and in what environmental conditions this or that ring was formed, to it the general structure and a wood structure, instead of a tree is important.