Aspen ordinary – a deciduous plant belonging to the genus Topol willow family, is widely distributed in temperate and cold climates of the Eurasian continent. This is a large, tall tree, which can reach a height of 35 m with a trunk diameter of 1 meter. It grows quite quickly and live long enough: up to 80-90 years. This is subject to an aspen development of various diseases, which is why high-quality copies of the large size and advanced age are extremely rare.
Appearance and physical and technical parameters
According to the structure of its wood of the aspen refers to the species without a kernel absently-vascular type. The wood of this tree has a whitish color with a slight greenish tint. This texture aspen is not very expressive and effective.
Annual rings and heart-rays on it almost invisible. In comparison with other members of deciduous trees, are used in industrial scale, it can be called rustic, therefore, to create a decorative products it is almost never used.
At the same time the material has good resistance to abrasion, lends itself well to cutting and turning. It is quite homogeneous, and due to this, the production of billets, it can be cut in any direction, without causing dents and chips.
Where growing aspen and its differences from poplar
Aspen vulgaris is one of the major Russian forest species and is found almost throughout the country, including the European part of, as well as the regions of the Far East and Siberia. Moreover, this tree can be found in Kazakhstan, Mongolia, Korea, China and many European countries.
It feels great on all types of soils in the forest-steppe and forest areas, mainly along rivers and gullies, as well as on the edges and areas of elevated terrain.
As a rule, this tree grows in the group, forming aspen, or a part of the mixed forests, combined with alder, larch, pine and birch. Due to deep-seated roots of aspen is not very sensitive to small forest fires.
So, what is different from aspen poplar:
Poplar bud spring is much faster with the release characteristic odor and appearance of tackiness. Aspen buds “come alive” slower.
Flowering aspen occurs in early spring, before the full opening of leaves. Poplar blooms in summer, spreading around him down, while the inflorescence aspen are long earrings-buds.
The leaves of these trees are different in shape.
The branches of aspen are more fragile compared with poplars.
The density, strength and moisture
One of the important indicators that have a direct impact on the quality and the final form of processed wood raw material is wood density. This term refers to the ratio of the mass of a certain moisture content of wood to its volume.
Thus, what is more humid wood portion of the tree, so it has a higher density. Furthermore, when assessing the wood used as wood conditional density index, representing the ratio of the mass of the test specimen in a completely dried state to its volume to limit hygroscopicity.
Indicators of density and apparent density of aspen are as follows:
The density in the dried condition of 470 kg / m3
Relative density of 400 kg / m3
density ratio at different levels of humidity:
The humidity level,% Coefficient of density, kg / m3
10% = 490 kg / m3
20% = 510 kg / m3
30% = 540 kg / m3
40% = 580 kg / m3
50% = 620 kg / m3
60% = 660 kg / m3
70% = 710 kg / m3
80% = 750 kg / m3
90% = 790 kg / m3
100% = 830 kg / m3
When freshly cut, 760 (82%)
Thus, it can be seen that wood has high aspen a density of 490 kg / m3. The natural moisture content of the material is in the form of freshly cut, on average, 82% of humidity at the maximum water absorption of 185%.
In aspen common these indicators are as follows.
The compressive strength in the direction along the fiber (at a humidity of 15%) – 374 kg / cm2.
When stretched in the direction along the fibers – 1450 kg / cm2.
When chipping works in a radial plane – 44 kg / cm2.
If static bending operation (at a humidity of 15%) – 673 kg / cm2.
In the implementation of impact bending in the tangential direction – 0.37 kgm / cm3.
According to the “Handbook of mechanical properties of wood” averages timber strength are as follows:
Strength limit at a static bend – 76.5 MPa.
Stretching along the grain – 121 MPa.
Compression parallel to grain – 43.1 MPa.
Cleaving the radial plane – 6.15 MPa.
In the tangential plane – 8.42 MPa.
Toughness – 84.6 kJ / m2.
The elastic modulus of aspen wood at a static bend is 11.2 GPa.
Aspen wood has good pliability to various kinds of processing, including cutting, bending, painting and polishing. In addition, it is well luschitsya.
The specific and volumetric weight of the wood
Among the important indicators on the basis of which the evaluation of quality of wood used include its specific and volumetric weight. To calculate the relative or specific weight of the wood material divided by the weight of the same amount of water.
In aspen it is at 12% humidity, 510 kg / m3. At the same time, unlike other species of trees, the value of this indicator in aspen are not constant, and can vary widely.
This is due to the structure of the material fibers which are characterized by high porosity. In other words, in the structure of business aspen wood always contains a certain amount of moisture, which renders it easily when dry and ease of picking up the same when placed in a moist environment.
Besides the specific gravity and bulk density to distinguish a unit volume or timber weight measurement which occurs at a humidity of 15% feedstock.
The chemical composition, hardness and durability qualities
The bulk of aspen wood consists of different organic substances, including the four main elements: oxygen, hydrogen, nitrogen and carbohydrate. In addition, it contains a number of minerals, forming at its combustion ash.
It was noted that the chemical composition of aspen wood changed depending on its age: in older aspen increased titanium content and reduced amount of copper, aluminum, silicon, iron, nickel, strontium, and zirconium. The quantitative ratio of the other elements remain unchanged.
Among the organic compounds in the composition of aspen wood are: Ash – 0.26%; pentosans – 27.47%; lignin – 21.81%; Cellulose – 41.77%. Indicator shock hardness aspen wood equal to 640 um / mm2. That is, it can be attributed to a number of soft rock.
The temperature of the combustion aspen, thermal conductivity
Like a number of other species such as softwood and hardwood trees, aspen is used as a raw material for the course of isothermal processes involving heat. In this connection particular importance is an indicator such as the calorific value of the wood.
In accordance with this criterion shall be determined as the amount of heat generated by one unit of weight of the wood material during combustion, aspen can be attributed to a little hot rocks. That is, the amount of heat generated by it will be very small.
The temperature of the combustion aspen – 612 degrees. The combustion of wood from this tree is fast enough, without the formation of carbon residue. Because of this, they are not very well suited for heating purposes, since their use is not possible to maintain a constant operating temperature in the furnace.
However, such wood are good for burning off the soot and clean the flue after the use of raw materials from softwood, releasing large amounts of soot and dirt.
It is also worth noting that compared to other trees aspen species has a high ability to absorb moisture. Its limit is hygroscopic 21.8 – 22.9%.
Despite its obvious shortcomings, aspen wood has a number of positive qualities that deserve evaluation “five points” on a five-point rating scale. Namely:
Decorative. Thanks to its pleasant silvery shade it with the ancient masters used to cover the roofs of the temples.
Ease of use. a lot of products are made of soft and supple aspen, including utensils.
The absence of resin. Because of this, it is often used for the production of baths.
Environmentally friendly and safe for humans.
Since raw wood of aspen is the building material having a different use of the spectrum, for him to meet a series of requirements and standards with which it must comply.
Standards for quality and appearance of semi-finished kind, specialized parts and other components for construction are contained in GOST 8242-88. When using raw wood from aspen to implement pyrolysis and charcoal burning is used GOST 24260-80.