Before carrying out any construction or repair, always calculate the required amount of material. For example: brick, metal or lumber: unedged, edged boards or lining. Typically, the seller provides wood delivery services, but it happens that this is not possible. And already the buyer himself has to decide this question: what kind of car needs to be ordered in order to bring the required amount of wood to the construction site?
Features of lumber
Even if the amount of wood in cubic meters is known, then the load on the choice of machine will still need to be calculated. Even knowing how much a cube of dry board weighs, the mass of a cubic meter of material on the market can vary significantly. And this will not only be due to a tree species, for example: pine or spruce, birch or cedar, but also the place of the log house, the humidity of the surrounding air, and even the time that has passed since the day the log house. The weight per cubic meter of the same tree will also differ from the degree of processing of the material. The mass of round timber, under the same conditions, will always be less than the mass of unedged forest. This is due to the fact that the packing density of the material in one cube will be different. It is not possible to stack the round timber tightly on top of each other; large voids will remain. The same applies to unedged boards. The surface will not be pressed firmly on the sides.
Therefore, when calculating the carrying capacity of a transport, it is necessary to focus on the transportation of the maximum possible mass of cargo. So, you need to know how much a cube of edged boards from pine of natural moisture weighs? Since this is the state of the tree during its felling, and therefore the maximum humidity and density.
Indicators affecting the weight of lumber
Wood moisture is a very important indicator that you need to pay attention to. When it is high, the tree swells, and when it is low, it dries out. All construction work is recommended to be performed with already dried lumber, in which the moisture content does not exceed 15-20%. Otherwise, the established raw forest, eventually drying up, will change its geometric dimensions (decrease) and thereby violate the integrity of the building.
Dried wood becomes more durable, lends itself well to decoration, is not susceptible to mold and insects, and retains its building qualities for a long time. Before drying, the remaining bark is removed. This is necessary for uniform drying and elimination of damage by insects (bark beetles).
Drying of the forest is carried out by specialists in the open air. The wood is stacked on pads between the rows so that air can freely pass through and dry the boards from all sides. It is advisable to place the drying place in a place where direct sunlight does not fall on the material, but there is good ventilation. The upper row of the stack must be pressed with a load to prevent deformation.
Weight calculation
Now we will calculate the weight of the most common lumber that you may encounter in the market.
We will calculate the mass using a calculator, according to the formula M \u003d V * ρ, kg, where:
- V - the volume of material necessary for the calculation, m3. In our case, this value is 1 m3;
- ρ is the density of wood, kg / m3. For freshly cut pine, the value is 820 kg / m3.
Substituting into the formula, we get:
- M \u003d 1 * 820 \u003d 820 kg.
Similarly, knowing the density of the material, you can calculate: how much does a cube of larch boards weigh:
- M \u003d 1 * 940 \u003d 940 kg.
And this means: no matter what size the edged board:
- 150x150x6000;
- 25x100x6000;
- 25x150x6000;
- 50x150x6000.
Their weight in one cube will be approximately equal, the main thing is that the composition of the wood, as well as the moisture indicator, remain unchanged, only the number of boards will differ.
The question arises, how much does a cube of dry boards weigh the same pine? This state of wood is taken at its moisture content up to 20%. Furthermore, density is - 520 kg / m3.
- M \u003d 1 * 520 \u003d 520 kg.
The difference in weight of one cube between pine natural humidity and dry will be - 300 kg! But for construction, not 1 m3 is purchased, but for example 100 or 500. Accordingly, the carrying capacity of the vehicle increases by 30 or 50 tons!
Therefore, when choosing lumber, it is important to know the humidity of the board. In order not to make a mistake in the choice of transport or the number of flights required to transport the entire forest.
Wood has been used in construction work since ancient times. Of course, because this material is still very popular due to the presence of excellent technical characteristics. Wood, in itself, is a natural material of a structured type, consisting of wood cells and pericellular voids, which, in turn, does not guarantee that one part of the wood will be equal to another of identical size. Therefore, so often, in the process of work, the question arises of calculating the required amount of a given material and such parameters as: weight of wood in general and weight of wood cube.
| Wood species | The percentage of humidity,% | ||||||||||
| Fresh | 100 | 80 | 70 | 60 | 50 | 40 | 30 | 25 | 20 | 15 | |
| Larch | 940 | 1100 | 990 | 930 | 880 | 820 | 770 | 710 | 700 | 690 | 670 |
| Poplar | 700 | 760 | 690 | 650 | 610 | 570 | 540 | 500 | 480 | 470 | 460 |
| Beech | 960 | 1110 | 1000 | 950 | 890 | 830 | 780 | 720 | 710 | 690 | 680 |
| Elm | 940 | 1100 | 1100 | 930 | 880 | 820 | 770 | 710 | 690 | 680 | 660 |
| Oak | 990 | 1160 | 1160 | 990 | 930 | 870 | 820 | 760 | 740 | 720 | 700 |
| Hornbeam | 1060 | 1330 | 1330 | 1130 | 1000 | 990 | 930 | 860 | 840 | 830 | 810 |
| Common spruce | 740 | 750 | 750 | 640 | 600 | 560 | 520 | 490 | 470 | 460 | 450 |
| Walnut | 910 | 1000 | 1000 | 850 | 800 | 750 | 700 | 650 | 630 | 610 | 600 |
| Linden | 760 | 830 | 830 | 710 | 660 | 620 | 580 | 540 | 540 | 530 | 500 |
| White Acacia | 1030 | 1330 | 1330 | 1190 | 1060 | 990 | 930 | 860 | 840 | 830 | 810 |
| Alder | 810 | 880 | 880 | 750 | 700 | 660 | 620 | 570 | 560 | 540 | 530 |
| Maple | 870 | 1160 | 1160 | 990 | 930 | 870 | 820 | 760 | 740 | 720 | 700 |
| Common ash | 960 | 1150 | 1150 | 930 | 920 | 860 | 800 | 740 | 730 | 710 | 690 |
| Siberian fir | 680 | 630 | 630 | 540 | 510 | 470 | 440 | 410 | 400 | 390 | 380 |
| Common pine | 820 | 850 | 850 | 720 | 680 | 640 | 590 | 550 | 540 | 520 | 510 |
| Caucasian Fir | 720 | 730 | 730 | 620 | 580 | 550 | 510 | 480 | 460 | 450 | 440 |
| Cedar pine | 760 | 730 | 730 | 620 | 580 | 550 | 510 | 480 | 460 | 450 | 440 |
| Birch | 870 | 1050 | 1050 | 890 | 840 | 790 | 730 | 680 | 670 | 650 | 640 |
| Aspen | 760 | 830 | 830 | 710 | 660 | 620 | 580 | 540 | 530 | 510 | 500 |
Depending on the type of construction work, it is necessary to measure wood in different ways. For the weight of m3 of wood, the density of the material is of particular importance, respectively, for the correct solution of the questions posed, it is necessary to determine the density value. There are two types of density:
Specific Gravity (Wood Density)
Volumetric weight (density of a structured physical body)
A wood substance is called a mass of solid wood materials without natural voids. This type of density is measured in laboratory conditions, as it requires additional measurements that are not feasible under normal conditions. For each wood of all types and species of trees, this value is constant and amounts to 1540 kg / m3.
The density of the wood itself is fairly easy to determine under normal conditions. To do this, just weigh a piece of wood and measure its volume. Process the data obtained by standard arithmetic operations according to the following formula: Y \u003d M / O, where Y is the specific gravity of the tree, M is the mass of wood, O is the occupied volume.
Table of volumetric weight of 1m3 of wood depending on humidity.
The density of wood substance, as has already been said, is a constant. However, wood has a multicellular fibrous structure of a complex type. Walls of wood substance play the role of a frame in the structure of wood. Accordingly, in each breed and tree species, the cellular structures, shapes and sizes of cells vary, as a result of which the specific gravity of the tree will be different, as well as different weight m3 of the tree.
Also, humidity plays a large role in changing the specific gravity of wood. Due to the structure of this material, with increasing humidity, the density of wood also increases. However, this rule does not apply to the density of woody matter.
Below is the specific gravity of wood. The table is compiled depending on the moisture content of the material and an indicator such as the weight of 1m3 of wood is calculated.
When designing various kinds of wooden structures, they often use such an indicator as the weight of those lumber from which they are supposed to be made. It would seem that such information can be obtained from specialized directories. However, in such literature, unfortunately, often only the weight of 1 m 3 of a bar or, for example, a board is often indicated. Lumber is often purchased not by cubic meters, but simply by the piece.
The length of the timber sold by woodworking workshops can be different. But more often than not, such enterprises sell lumber of 6 m to the population. So what, for example, can be the weight of a bar of natural humidity 150x150x6000 mm? To find out, you will have to make some simple independent calculations.
What determines the weight of lumber
It is clear that the more moisture is contained in the timber, the harder it will be. However, the weight of such lumber depends not only on this factor. Performing the calculations, in this case, the characteristics of the actual wood species itself must be taken into account. Indeed, for example, an oak beam in any case will be heavier than lumber from birch.
What is natural humidity?
So, how do you calculate the weight of a wooden beam of natural humidity 150x150x6000 mm of a particular breed? To make such calculations is actually not too difficult. However, before proceeding with the calculations, it’s still worthwhile to decide on the concept of “natural humidity”.
In construction and in the manufacture of various products, only wood with a moisture content of not more than 12-15% is used. And even such boards and timber before use in most cases are additionally dried for some time.
Humidity only sawn wood will, of course, be very high. In any case, its indicator will exceed 12-15% significantly. It is such humidity that is commonly called natural. That is, we ultimately need to find out the weight of a wooden bursa of standard length with a section of 15x15 cm, made of freshly sawn wood.
We take into account the breed
The basis for such an operation should be taken from the table of weight of lumber in cubic meters.
Perform calculations in this case as follows:
recognize the number of bars of a given length and section of 1 m 3;
by simple division, the mass of one such unit of lumber is calculated.
In one cubic meter of timber, measuring 150x150x6000 mm, thus, 1: 0.15: 0.15: 0.15: 6 \u003d 7.4 pieces will be contained. To find out the weight of a beam, in this case you need:
look at the weight of a cubic meter for a given specific wood species;
divide this parameter by the number of bars per cubic meter.
For example, at a moisture content of 15%, 1 m 3 of pine lumber weighs, according to the table above, 440 kg. That is, the calculation in this case will look like this:
440 / 7.4 \u003d 59.5 kg.
It is also easy to determine that the beam weight of 150x150x6000 mm from a larch of the same humidity will be 90.5 kg. For aspen, this figure will be 67.6 kg.
Instructions for calculating the weight of a bar of natural humidity 150x150x6000 mm
Thus, the weight of lumber of a given moisture content is not too difficult to determine. To do this, you just need to solve two simple mathematical examples. But what will be the weight of a bar of natural humidity 150x150x6000 mm? In order to determine this, among other things, you need to know the actual last indicator for a particular type of wood.
You can also get such information from special tables. So, for example, the natural humidity of pine is 60-100%, larch - 50-70%, birch - 70-90%. These parameters should be taken in this case to calculate the weight. For obvious reasons, exact calculations will not be possible.
So, how much does a timber weigh 150x150x6000 mm of natural humidity? Based on the data in the table above:
pine beams of such dimensions will weigh from 580 / 7.4 \u003d 78.3 (60%) to 730 / 7.4 \u003d 98.6 (100%) kg;
the weight of a bar of natural humidity 150x150x6000 mm from larch will vary from 820 / 7.4 \u003d 110.8 kg to 930 / 7.4 \u003d 125.7 kg.
In the same way, you can calculate the beams of such dimensions of natural moisture for any other breed.
Specific gravity
There are only two types of density of wood:
volumetric weight (density of the physical body of wood itself);
specific specific wood fibers).
Above, we considered a method for determining the volumetric weight of a beam 150x150x6000. Natural humidity or the set value in such calculations is an important indicator. Indeed, in this case, the weight also depends on the amount of moisture contained in the wood structure. But if desired, the specific density index can be calculated for the beams.
This can be done using the table above. Calculations in this case will be carried out without taking into account humidity. That is, to calculate, you need to find the number of beams of a certain size in a cubic meter and simply divide the indicator from the table by the resulting number.
Thus, for pine 520 / 7.4 \u003d 70.3 kg is the specific gravity of the beam 150x150x6000. Natural humidity - permissible operational or some other - in this case are not taken into account.
The company Drova72 conducted an experiment, we weighed 1 folding cube (storage meter) of chopped birch firewood, natural humidity, ~ 50%. The results of this experiment will be described in more detail below.
This experiment in no way claims to be - “scientific” or “100% objective”, rather, a cross between information from the Internet and laboratory research. Nevertheless, this is the first step towards truth and objectivity.
Next time we will repeat the experiment and try to find a moisture meter, as well as shoot the entire process on video.
In short, the results
With humidity ~ 50% and log length ~ 50cm:
- 1 folding cube weighs ~ 561 kg;
- 1 dense cubic cube weighs ~ 790 kg.
In the text below, we detail the essence of the experiment. The calculation is made on the basis of information from GOST "a 3243-88 and the sawmill reference.
Why do we need this?
Small digression
The volume of firewood in warehouse meters is measured by multiplying the length, width and height of the woodpile. But, the concept of “1 folding cube of firewood” is rather vague, because firewood can be stacked with different laying density and there is no GOST or regulation that would explain what a “packing density" is and how to measure it. That is, the same amount of firewood (1 conditional storage meter) can be stacked from ~ 0.7 to ~ 1.3 warehousemeter, depending on the density of laying and the state of the logs (their curvature, the presence of knots).
For clarity, look at the photo below. Obviously, the firewood was laid on the right thoroughly and the number of poles in this woodpile is greater than in the one on the left. In both cases, the volume of firewood in the warehouse meters will be the same, but the mass is different. Those. in fact, the amount of firewood in the photo on the left is less. 
In the photo above, please do not pay attention to the different type of firewood, this image shows the density of stacking firewood in the woodpile.
Specifics
Sometimes we have disagreements with our customers regarding the volume of firewood in storage meters. We brought the firewood to the stacking in one volume, the client shifted the firewood into his wood, measured it and he got a volume less than the originally declared.
In the example above, the odds are almost always due to packing density. Therefore we decided weigh 1 folding cube of birch firewood and correlate its weight (mass) with the data, which are presented in GOST 3243-88 and in the Handbook on lumbering, Moscow, Forestry publishing house, 1980
By comparing the weight of our firewood storage machine with the data from the above sources, we will see if we stack the firewood tightly enough before delivering it to the customer.
Sequencing:
- First, we put 1 folding cube in the woodpile.
- Weigh this cube on the scales.
- We will compare the obtained weight with the data from GOST 3243-88 and the Handbook on sawmilling.
According to various sources, the humidity of freshly sawn birch can vary from 60 to 80%. We buy wood birch, which is harvested (sawn) from 1 to 4 months ago from the moment when it is brought to us for further processing. Humidity of such a birch is on average 40-50%. We will do the calculation based on 50% humidity.
In the directory for sawmilling, the weight of a dense cube of ordinary birch at a humidity of 50% is 790 kg. To translate the weight of the warehouse meter into a dense cube (or vice versa) you need to apply the coefficient. We will take it from GOST 3243-88, with a log length of up to 0.5 meters of chopped hardwood - the coefficient is 0.71.
790 * 0.71 \u003d 560.9 kg
Those. the mass of our chopper of chopped birch firewood should be at least 561 kg.
Weigh
Conclusions and Comments
First of all, we wanted to test ourselves, because sometimes doubts arose about honesty towards our customers. Now doubts are dispelled. Our stacking density and volume of firewood in folding cubic meters meets the necessary requirements.
If we again refer to the sawmill handbook (Note 1), then it is obvious that not always the weight of 1 folding cube at a humidity of 50% will be 560.9 kg, because the weight of one dense cube 790kg - is an average value and can range from 553kg to 1027kg. And, therefore, 1 stereometer of chopped birch firewood (taking into account the coefficient of 0.71) can weigh from 392kg to 729kg. This is probably due to the different density of trees and poles.
Of course, this experiment cannot be considered 100% objective, because at least a moisture meter is needed to determine moisture. Our forest can have different humidity because There are many suppliers and the terms of harvesting and delivery are different for everyone, respectively, the moisture content of the forest can vary from 30 to 60%.
If you have any suggestions or comments on this material - please write to our email: [email protected]website.
When organizing the transportation of timber, tree density is an important indicator in the selection of a timber truck and calculating the cost of transportation. This will help to avoid overload, which accordingly will result in a fine.
For the weight of m3 of wood, the density of the material is of particular importance, respectively, for the correct solution of the questions posed, it is necessary to determine the density value. There are two types of density: volume weight (density of a structured physical body) and specific gravity (density of wood substance).
Volumetric weight of wood
The weight of a cubic meter of wood depends on the type of wood and humidity.Volumetric tree weight calculator.
Tree Acacia white Birch Beech Elm Oak Hornbeam Norway spruce Maple Linden Larch Alder Walnut Aspen Siberian fir Caucasian fir Common pine Cedar pine Poplar
Volume, m3:
Wood specific gravity
A wood substance is called a mass of solid wood materials without natural voids. This type of density is measured in laboratory conditions, as it requires additional measurements that are not feasible under normal conditions. For each wood of all types and species of trees, this value is constant and amounts to 1540 kg / m3. However, wood has a multicellular fibrous structure of a complex type. Walls of wood substance play the role of a frame in the structure of wood. Accordingly, in each breed and tree species, the cellular structures, shapes and sizes of cells vary, as a result of which the specific gravity of the tree will be different, as well as different weight m3 of the tree.
Also, humidity plays a large role in changing the specific gravity of wood. Due to the structure of this material, with increasing humidity, the density of wood also increases. However, this rule does not apply to the density of woody matter.
| № | Wood species | The percentage of humidity,% | ||||||||||
| 15 | 20 | 25 | 30 | 40 | 50 | 60 | 70 | 80 | 100 | Fresh. * | ||
| 1 | Larch | 670 | 690 | 700 | 710 | 770 | 820 | 880 | 930 | 990 | 1100 | 940 |
| 2 | Poplar | 460 | 470 | 480 | 500 | 540 | 570 | 610 | 650 | 690 | 760 | 700 |
| 3 | Beech | 680 | 690 | 710 | 720 | 780 | 830 | 890 | 950 | 1000 | 1110 | 960 |
| 4 | Elm | 660 | 680 | 690 | 710 | 770 | 820 | 880 | 930 | 990 | 1100 | 940 |
| 5 | Oak | 700 | 720 | 740 | 760 | 820 | 870 | 930 | 990 | 1050 | 1160 | 990 |
| 6 | Hornbeam | 810 | 830 | 840 | 860 | 930 | 990 | 1060 | 1130 | 1190 | 1330 | 1060 |
| 7 | Common spruce | 450 | 460 | 470 | 490 | 520 | 560 | 600 | 640 | 670 | 750 | 740 |
| 8 | Walnut | 600 | 610 | 630 | 650 | 700 | 750 | 800 | 850 | 900 | 1000 | 910 |
| 9 | Linden | 500 | 530 | 540 | 540 | 580 | 620 | 660 | 710 | 750 | 830 | 760 |
| 10 | White Acacia | 810 | 830 | 840 | 860 | 930 | 990 | 1060 | 1190 | 1300 | 1330 | 1030 |
| 11 | Alder | 530 | 540 | 560 | 570 | 620 | 660 | 700 | 750 | 790 | 880 | 810 |
| 12 | Maple | 700 | 720 | 740 | 760 | 820 | 870 | 930 | 990 | 1050 | 1160 | 870 |
| 13 | Common ash | 690 | 710 | 730 | 740 | 800 | 860 | 920 | 930 | 1030 | 1150 | 960 |
| 14 | Siberian fir | 380 | 390 | 400 | 410 | 440 | 470 | 510 | 540 | 570 | 630 | 680 |
| 15 | Common pine | 510 | 520 | 540 | 550 | 590 | 640 | 680 | 720 | 760 | 850 | 820 |
| 16 | Caucasian Fir | 440 | 450 | 460 | 480 | 510 | 550 | 580 | 620 | 660 | 730 | 720 |
| 17 | Cedar pine | 440 | 450 | 460 | 480 | 510 | 550 | 580 | 620 | 660 | 730 | 760 |
| 18 | Birch | 640 | 650 | 670 | 680 | 730 | 790 | 840 | 890 | 940 | 1050 | 870 |
| 19 | Aspen | 500 | 510 | 530 | 540 | 580 | 620 | 660 | 710 | 750 | 830 | 760 |
* Fresh. - Freshly cut tree