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Weight of raw wood. Carrying out calculations of waste from cutting down trees and shrubs. Volumetric weight of wood




WEIGHT OF 1 CUBIC METER (VOLUME WEIGHT) OF BEAM, BOARDS AND MOLDINGS

The weight of lumber (beams, boards, logs), molded products (lining, trim, plinths, etc.) and other wood products depends mainly on the moisture content of the wood and its species.

The table shows the weight values ​​of 1 cubic meter of wood (volume weight) depending on the type of wood and its moisture content.

Weight table 1 cu. m (bulk weight) timber, boards, lining made of wood of various species and humidity

Depending on the moisture index, measured as a percentage of the mass of water contained in wood to the mass of dry wood, wood is divided into the following moisture categories:

    Dry wood (humidity 10-18%) is wood that has undergone technological drying or has been stored in a warm, dry room for a long time;

    Air-dry wood (moisture content 19-23%) is wood with an equilibrium moisture content, when the moisture content of the wood itself is balanced with that of the surrounding air. This degree of humidity is achieved when long-term storage wood in natural conditions, i.e. without the use of special drying technologies;

    Raw wood (moisture 24-45%) is wood that is in the process of drying from a freshly cut state to an equilibrium state;

    Freshly cut and wet wood (moisture content over 45%) is wood that has been recently cut or has been in water for a long time.

WEIGHT OF ONE BEAM, ONE EDGING AND FLOORS, LININGS

The weight of one beam, board or any molded product also depends on the moisture content of the wood from which they are made and its species. The table shows the data for the most used wood in construction - pine with wet moisture for timber and edged boards and air-dry moisture for floorboards and lining.

Weight table of one beam, one board and lining




NUMBER OF BARS, BOARDS AND CLADDING IN 1 CUBE M

The number of pieces of any lumber or molded product in 1 cubic meter depends on its dimensions: width, thickness and length. Data on the number of lumber in 1 kb. m are presented in the table.
  1. Tree species groups
  2. Humidity dependence
  3. Impact on wood quality

The density of wood is one of the main characteristics of a cubic meter of material, which is taken into account when calculating structures, choosing raw materials for the production of various products. The term refers to the ratio of the mass of the material to the measured volume.

What can be the density of the forest

Different tree species have approximately the same composition, therefore, in dry form, the absolute specific gravity will be the same for everyone. Its average value is 1.54 (dimensionless value). But in the table of wood density for different species, their numbers are given. The fact is that in a completely dry state it is almost impossible to measure the absolute parameter. To do this, it is necessary to completely get rid of moisture in the test sample, to eliminate air voids. In practice, as it turned out, it is difficult to fix the parameter, and it is unsuitable for calculations.

To determine the density of lumber, the calculation of its specific gravity is more suitable..

It is affected by:

  • humidity;
  • rock porosity.

The specific gravity of wood has the form of an average value of density calculations in its different states. Sources may vary slightly. The difference is due to a change in the level of moisture inside the trunk. To avoid confusion, we present a table with the average values ​​of the specific gravity for each individual moisture level of different types of wood in ascending order.

Table of wood density of different moisture content (kg / m 3)


Tree species groups

Typically, the tabular value of the density of timber and other lumber is measured at a moisture content of 12%. Depending on the value obtained, tree species are divided into 3 groups:

  1. With a low bulk density (less than 540 kg / m 3). These include coniferous trees: pine, spruce, fir, cedar and some deciduous. These are all types of alder, poplar, linden, aspen, chestnut.
  2. With an average specific gravity of 550–740 kg / m 3: beech, elm (elm), larch, all types of maple, mountain ash, apple tree, ash.
  3. With a high level of density over 750 kg / m 3: birch, oak (Araksinsky, chestnut-leaved), hornbeam, dogwood, pistachio.

Of course, this is an incomplete list of breeds. According to the indicated wood density values ​​in the table, it is possible to determine whether the species belongs to the group.

Humidity dependence

All lumber contains water. Its quantity mainly determines the density of the timber and other raw materials: the more moisture in the product, the higher the weight in the measured volume.

The specific gravity of wood in the table is given in average values, since the amount of moisture in one volume is constantly changing - this is a relative value.

The changes are due to:

  • external weather conditions (rain, fog, snow);
  • anthropogenic factor (wetting due to human activity).

Thus, a completely dry board practically does not exist. Wood moisture content is always above 0%. This indicator can be determined using a special device - a moisture meter.

Impact on wood quality

The average specific gravity is the main characteristic of raw materials when making calculations, since the value includes an average estimate of the tests of lumber in different states of water saturation.

According to the laws of physics, the calculated density is directly related to the strength of the material: the higher the specific gravity of the volume of the product, the greater the load it can withstand. This rule also applies to wood.

Let's look at an example:

  • Oak has a high specific gravity and is famous for its reliability and durability. It has almost no empty pores, the entire volume is filled with strong wood fibers and moisture. The load-bearing structures of houses and industrial facilities are made from oak. Wood with a high specific gravity is rigid, practically does not bend.
  • Cedar and birch beams are characterized by low volumetric weight, therefore they are not used to create load-bearing elements of the skeleton of structures. These breeds are more suitable for finishing work, where the load on the product is minimal. Wood with low porosity is plastic, lends itself to bending.

Dependence of density and thermal conductivity

This indicator is important for choosing a tree when harvesting firewood. The dependence is direct: the higher the density index, the more fuel in the chocks, the longer they will burn. Wood species with a high mass-to-volume ratio are called solid fuels. They burn for a long time, give a good heat, but due to the dense structure it is difficult to prick. The advantage of firewood and fuel from light wood species is their flexibility in sawing and chopping, but they have a relatively small energy reserve. Logs will burn for a much shorter amount of time.

How much does 1 cube of tree branches weigh, weight of 1 m3 of branches. The number of kilograms in 1 cubic meter of branches and shrubs, the number of tons in 1 cubic meter, kg in 1 m3. Bulk density of tree branches to convert to tons and specific gravity of tree branches and bushes.

What do we want to know today? How much does 1 cube of branches weigh, the weight of 1 m3 of tree branches? No problem, you can find out the number of kilograms or the number of tons at once, the mass (the mass of one cubic meter, the weight of one cube of tree branches and bushes, the mass of one cubic meter, the weight of 1 m3 of twigs, twigs, rods, brushwood) are indicated in table 1. If someone it’s interesting, you can skim through the small text below, read some explanations. How is the amount of substance, material, liquid or gas we need measured? Except in those cases when it is possible to reduce the calculation of the required quantity to the calculation of goods, products, elements in pieces (piece count), it is easiest for us to determine the required quantity based on volume and weight (mass). In everyday life, the most familiar unit of measurement for us is 1 liter. However, the number of liters suitable for household calculations is not always an applicable way to determine the volume for economic activity. In addition, liters in our country have not become a generally accepted "production" and trade unit of volume. One cubic meter, or in an abbreviated version - one cube, turned out to be quite a convenient and popular unit of volume for practical use. We are used to measuring almost all substances, liquids, materials and even gases in cubic meters. It's really convenient. After all, their cost, prices, rates, consumption rates, tariffs, supply contracts are almost always tied to cubic meters (cubes), much less often to liters. No less important for practical activities it turns out that knowledge is not only of volume, but also of the weight (mass) of the substance occupying this volume: in this case we are talking about how much 1 cube weighs (1 cubic meter, 1 cubic meter, 1 m3). Knowledge of mass and volume gives us a fairly complete picture of quantity. Visitors to the site, asking how much 1 cube of branches and shrubs weighs, often indicate specific units of mass in which they would like to know the answer to the question. As we have noticed, most often they want to know the weight of 1 cubic meter (1 cubic meter, 1 cubic meter, 1 m3) in kilograms (kg) or tons (tons). In fact, you need kg/m3 or t/m3. These are closely related units of quantity. In principle, a fairly simple independent conversion of weight (mass) from tons to kilograms and vice versa is possible: from kilograms to tons. However, as practice has shown, for most visitors to the site, a more convenient option would be immediately find out how many kilograms weigh 1 cube (1 m3) of branches or how many tons weigh 1 cube (1 m3) of tree branches, without converting kilograms into tons or vice versa - the number of tons into kilograms per cubic meter (one cubic meter, one cubic meter, one m3). Therefore, in table 1, we indicated how much 1 cubic meter of tree branches and bushes weighs (1 cubic meter, 1 cubic meter) in kilograms (kg) and tons (tons). Choose the column of the table that you need yourself. By the way, when we ask how much 1 cubic meter (1 m3) weighs, we mean the number of kilograms or the number of tons. However, from a physical point of view, we are interested in density or specific gravity. The mass of a unit volume or the amount of a substance placed in a unit volume is bulk density or specific gravity. In this case bulk density of branches and shrubs and specific gravity of tree branches. Bulk or bulk density of branches of trees and bushes and specific gravity in physics are usually measured not in kg / m3 or in tons / m3, but in grams per cubic centimeter: g / cm3. Therefore, in Table 1, the specific gravity of branches and shrubs and the bulk density of branches (synonyms) are indicated in grams per cubic centimeter (g / cm3)

Table 1. How much does 1 cube of tree branches weigh, the weight of 1 m3 of branches. Bulk density of branches and shrubs and specific gravity in g/cm3. How many kilograms in a cube of branches, tons in 1 cubic meter of branches, kg in 1 cubic meter, tons in 1 m3.

Starting the construction of a house, or making repairs, sometimes you have to deal with questions that seem to be simple at first glance, but you can’t give an answer to them right away. It seems awkward to address such a question to specialists, but you need to know for sure. For those who can access the Internet, it’s easier - I typed in the search engine “How much does a cube of wood weigh” and in half a minute I got an exhaustive result. And by the way, really, how much?

Influence of humidity on wood weight

The weight of wood does not always have the same indicator. What does it depend on? First of all, from the moisture of the tree. If we compare, for example, oak and birch, it turns out that a cubic meter of oak weighs 700 kg, and birch weighs 600 kg. But it may be otherwise. Weighing a cubic meter of birch, we get 900 kg, and oak will show the same 700. Or in both cases it will be 700 kg. Why are there such different numbers? In this case, the moisture content of the wood plays a role.

There are four degrees of humidity: dry (10-18%), air-dry (19-23%), damp (24-45%) and wet (above 45%). Thus, it turns out that different breeds at the same humidity, they have different weights, as in the first example above. If the humidity is not the same, then the weight can fluctuate in one direction or another. The standard humidity is 12%.

Different density - different weight

Another factor that affects the weight of wood is its density. The most high density for iron and ebony - from 1100 to 1330 kg / m 3. Boxwood and bog oak are close to them - 950-1100. In ordinary oak, beech, acacia, pear, hornbeam, the density is about 700 kg / m 3. It is even lower in pine, alder, bamboo - 500 kg / m 3. And the lowest is at the cork tree, only 140 kg / m 3.

Why do you need to know the weight of a cubic meter of wood

Having knowledge in this area is sometimes very important. By purchasing construction material, its amount is impossible for a non-specialist to determine by eye. Knowing the dimensions of the timber or lining, the material from which they are made and its moisture content, simple calculations allow us to determine the weight of the purchased goods. How much does a cube of wood weigh - in this case, the answer to this question will help you figure out whether the seller released the goods to you correctly.

Heat dissipation of wood

In addition, there is another indicator - heat transfer. She will come to the aid of those who use wood as firewood for heating. The higher the hardness, i.e. the density of the wood species, the higher its calorific value. Of course, no one will heat the room with boxwood, but choosing between linden and pine or birch and acacia, you can get much more heat if you know which of these species are the hardest. Information about the density of each tree can be gleaned from the tables, since all this information is systematized for ease of use.

Weight of dense cubic meter, kg

Breed Humidity, %
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
- Dahurian 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
- eastern 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
- Araksinsky 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
- ordinary 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 390 400 410 420 430 470 500 530 570 600 630 660
- whole leaf 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:
- Manchu 640 660 680 690 710 770 820 880 930 990 1040 1100
- ordinary 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

The table shows the average weight values. The possible maximum and minimum values ​​of the mass are respectively 1.3 and 0.7 of its average value

Softwood lumber is on average considered lighter than hardwood lumber. They are distinguished by ease of processing and durability - resistance to decay, and therefore are often used for carved facade decoration. In addition, it is from coniferous species that the longest sawn timber (more than 6 meters) is produced. Not surprisingly, they are traditionally in high demand.

The weight of lumber depends on the type of wood and humidity.

However, determining their weight is not such a simple matter. Although the main conifers - pine and spruce - are obviously lighter than oak or beech, in fact, if the task is to transport a significant amount of lumber to road transport, you can expect a catch. “Fresh” wood can often have an unpredictable weight: lumber, depending on the processing stage, as well as on the forest area where the trees were grown, can vary greatly in properties. Here you need to understand specifically.

The weight of softwood lumber according to GOST and in practice

First of all, humidity plays a decisive role in the properties of wood. Raw wood and dried wood can vary in density by half. This is especially true for conifers.

Raw forest - spruce or pine - resin gives additional mass. Humidity depends on the cutting season, on growing conditions, on the part of the trunk from which lumber is made.

In particular, with regard to pine, a tree harvested after the middle of winter (January) will be 10-20% lighter than an autumn one. If the forest area is located in an area with high standing groundwater (closer than 1.5 m to the surface), the tree will be “overloaded” with water, especially the lower part of the trunk. On the other hand, the "sucked" forest - the one from which the resin was previously collected - will be more than 1.5 times lighter than the untouched one. Needless to say, the weight of 1 m3 of freshly cut wood will also depend heavily on the humidity of the climate and similar circumstances.

In processed form, lumber is more or less equal in weight, but still, those made from the lower part of the trunk are more likely to be heavier: they are initially more moist and retain more water with the same drying. In addition, according to statistics, the beam turns out to be lighter than boards equal to it in cubic capacity (especially unedged ones), even made from the same log: the core of the trunk, from which the beam is cut, is naturally looser, boards are made not only from the core.

In a word, the mass of raw softwood lumber differs greatly from the mass of dry lumber. On average, the weight of one cubic meter of dry pine is 470 kg, and that of raw pine is 890 kg: the difference is almost 2 times. The weight of 1 m3 of dry spruce is 420 kg, and the weight of 1 m3 of raw spruce is 790 kg.

According to GOST, the standard moisture content for wood is 12%. Under such conditions, spruce has a density of 450 kg / m3, pine - 520 kg / m3, they belong to light species. Among conifers, Siberian fir is even lighter: 390 kg/m3. Nevertheless, there are also heavier species of conifers: larch belongs to the medium-density varieties of wood, the weight of 1 m3 is 660 kg, it surpasses birch and is almost as good as oak.

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