How much does a wood cube weigh?

Content
  1. Specific gravity
  2. Volume weight
  3. Calculations
  4. How much do sawdust weigh?
  5. Conclusion

The volume of wood - in cubic meters - is not the last, albeit decisive, characteristic that determines the cost of a particular order of wood material. It is also important to know the density (specific gravity) and the total mass of the batch of boards, beams or logs requested by a particular client.

Specific gravity

Specific gravity of a cubic meter of wood - in kilograms per cubic meter - is determined by the following factors:

  • moisture content in wood;
  • density of wood fibers - in terms of dry wood.

The wood cut and harvested at the sawmill differs in weight. Depending on the species, type of wood - spruce, pine, birch, acacia, etc. - a dry tree with a specific name of the harvested product has a different density. According to GOST, maximum permissible deviations of the mass of one cubic meter of dry wood are allowed. Dry wood has a moisture content of 6–18%.

The fact is that completely dry wood does not exist - there is always a small amount of water in it... If wood and sawn timber did not contain water (0% moisture), then the tree would lose its structure and crumble under any tangible load on it. A bar, a log, a board would quickly crack into individual fibers. Such a material would only be good as a filler for wood-based composite materials, such as MDF, in which bonding polymers are added to wood powder.

Hence, after deforestation and timber harvesting, the latter is qualitatively dried. Optimal term - year from the date of procurement. For this, wood is stored in a covered warehouse, where there is no access to precipitation, high humidity and dampness.

Although the timber at the base and in the warehouses is sold in “cubes”, its high-quality drying is important. Under ideal conditions, the tree is dried in an indoor area with all steel, metal walls and ceilings. In summer, the temperature in the warehouse rises above +60 - especially during the sultry period. The hotter and drier, the sooner and better the wood will dry out. It is not stacked close to each other, like, say, bricks or steel profiled sheet, but laid out so that an unobstructed flow of fresh air is provided between the beams, logs and / or planks.

The drier the wood is, the lighter it is - which means that a truck will spend less fuel on delivering wood to a specific client.

Drying stages - different degrees of humidity. Let's imagine that the forest was harvested in the fall with frequent rains. The trees are often wet, the wood is full of water. A wet tree that has just been cut in such a forest contains almost 50% moisture. Further (after storage in a covered and closed space with supply and exhaust ventilation), it goes through the following drying stages:

  • raw wood - 24 ... 45% moisture;
  • air-dry - 19 ... 23%.

And only then it becomes dry. The time has come to sell it profitably and quickly, until the material is damp and spoiled by mold and mildew. A moisture value of 12% is taken as an averaged standard. Secondary factors affecting the specific gravity of a tree include the time of the year when a particular batch of forest was cut down, and the local climate.

Volume weight

If we are talking about the volume of wood, close to one cubic meter, its weight is recalculated in tons. For fidelity, blocks, stacks of wood are re-weighed on auto scales that can withstand a load of up to 100 tons. Knowing the volume and type (wood species), they determine the density group of a particular wood.

  • Low density - up to 540 kg / m3 - inherent in spruce, pine, fir, cedar, juniper, poplar, linden, willow, alder, chestnut, walnut, velvet, as well as wood materials from aspen.
  • Average density - up to 740 kg / m3 - corresponds to larch, yew, most birch species, elm, pear, most oak species, elm, elm, maple, sycamore, some types of fruit crops, ash.
  • Anything that weighs more than 750 kg in a cubic meter volume, refers to acacia, hornbeam, boxwood, iron and pistachio trees, and hop grab.

The volumetric weight in these cases is recalculated according to the same average 12% humidity. So, for conifers, GOST 8486-86 is responsible for this.

Calculations

The weight of a dense cubic meter of wood, depending on the species (deciduous or coniferous), the type of tree and its moisture content, can be easily determined from the table of values. Moisture content of 10 and 15 percent in this sample corresponds to dry wood, 25, 30 and 40 percent - wet.

View

Moisture contents,%

10 15 20 25 30 40 50 60 70 80 90

100

Beech 670 680 690 710 720 780 830 890 950 1000 1060

1110

Spruce 440 450 460 470 490 520 560 600 640 670 710

750

Larch 660 670 690 700 710 770 820 880 930 990 1040

1100

Aspen 490 500 510 530 540 580 620 660 710 750 790

830

Birch
fluffy 630 640 650 670 680 730 790 840 890 940 1000

1050

ribbed 680 690 700 720 730 790 850 900 960 1020 1070

1130

daurian 720 730 740 760 780 840 900 960 1020 1080 1140

1190

iron 960 980 1000 1020 1040 1120 1200

1280

Oak:
petiolate 680 700 720 740 760 820 870 930 990 1050 1110

1160

Oriental 690 710 730 750 770 830 880 940 1000 1060 1120

1180

Georgian 770 790 810 830 850 920 980 1050 1120 1180 1250

1310

araksin 790 810 830 850 870 940 1010 1080 1150 1210 1280

1350

Pine:
cedar 430 440 450 460 480 410 550 580 620 660 700

730

siberian 430 440 450 460 480 410 550 580 620 660 700

730

common 500 510 520 540 550 590 640 680 720 760 810

850

Fir:
siberian 370 380 390 400 410 440 470 510 540 570 600

630

white-haired 390 400 410 420 430 470 500 530 570 600 630

660

whole-leaved 390 400 410 420 430 470 500 530 570 600 630

660

white 420 430 440 450 460 500 540 570 610 640 680

710

Caucasian 430 440 450 460 480 510 550 580 620 660 700

730

Ash:
Manchurian 640 660 680 690 710 770 820 880 930 990 1040

1100

normal 670 690 710 730 740 800 860 920 980 1030 1090

1150

sharp-fruited 790 810 830 850 870 940 1010 1080 1150 1210 1280

1350

For example, ordering 10 spruce boards measuring 600 * 30 * 5 cm, we get 0.09 m3. Qualitatively dried spruce wood of this volume has a weight of 39.6 kg. Calculation of the weight and volume of edged boards, beams or calibrated logs determines the cost of delivery - along with the distance of the customer from the nearest warehouse to which the order was placed. Converting into tons of large volumes of wood decides which transport is used for delivery: a truck (with a trailer) or a railroad car.

Driftwood - wood felled by hurricanes or floods; and debris carried downstream by rivers as a result of natural disturbances or human activities. The specific weight of driftwood is in the same range - 920 ... 970 kg / m3. It does not depend on the type of wood. The moisture content of driftwood reaches 75% - from frequent, constant contact with water.

The cork has the lowest volumetric weight. Cork tree (more precisely, its bark) has the highest porosity among all wood materials. The structure of the cork is such that this material is filled with numerous small voids - in consistency, structure, it approaches a sponge, but retains a much more solid structure. The elasticity of the cork is noticeably higher than that of any other wood material of the lightest and softest species.

An example is champagne bottle corks. The collected volume of such material, equal to 1 m3, weighs 140–240 kg, depending on humidity.

How much do sawdust weigh?

GOST requirements do not apply to sawdust. The fact is that the weight of lumber, in particular sawdust, depends more on their fraction (grain size). But the dependence of their weight on humidity does not change depending on the state of the wood material: (un) processed wood, shavings as waste from a sawmill, etc. In addition to tabular counting, an empirical method is used to determine the weight of sawdust.

Conclusion

Having correctly calculated the weight of a particular batch of wood, the deliveryman will take care of its prompt delivery. The consumer pays attention to the species and type, the condition of the wood, its weight and volume even at the stage of ordering.

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