How much does a cube of aspen fir pine firewood weigh. Calculation of the weight and the required number of edged boards

Go to alternative sources energy makes us pay attention to wood. It was it that our ancestors used to heat their homes and cook food. Furnaces, fireplaces, solid fuel boilers- for all these devices you need a tree, namely firewood. But all plants are different, and trees, having a different structure and chemical composition, differ in such characteristics as calorific value, weight, density, humidity.

How much does firewood weigh?

How to determine weight of 1 cube of firewood? Does it matter what kind of firewood you buy, fresh cut or dried? Knowing this will help specific gravity, humidity and other features of wood.

More than 200 species of trees and shrubs grow on the territory of our country. They all burn differently, some faster, others slower, some give off a lot of heat, and some less. When choosing a tree for a firebox, it is better to focus on a middle-aged tree, do not take too young or too old. They burn for the longest time and give off the most heat.

Also, the amount of heat given off directly depends on the density and dryness of the firewood. Wood with a moisture level of 15 - 20% is considered the most suitable for sending into the furnace, and in a freshly sawn tree, moisture is not less than 50%. Part of the heat will be spent on the evaporation of water, so the efficiency of wet firewood is much lower. Yes and dry wood weight much lower than wet ones.

The weight of wood depends on:

structure of wood cells, their moisture content,
wood density,
parts of the plant (the heaviest parts are branches, the lightest are the base of the trunk),
salt and resin content.

The weight of firewood can be determined empirically, that is, simply weigh a small piece of wood of a certain volume and, by simple calculations, find out its density (the ratio of mass in kilograms to volume in m3). But such a procedure is not convenient in all cases.

Tables of average wood weights will help make calculations easier. Conditional values are given for the material moisture content of 15 - 20%. Interestingly, changing the moisture content of a tree does not change its density, although it greatly affects the value of the specific gravity.

Table of some reference values for the density of wood and the weight of firewood during loading

wood species	Specific gravity g/cm3	Specific weight kg/m3	Loading weight of firewood kg/m3
Ash, beech	0,68	650 - 750	480
Birch	0,65	620 - 650	450
Oak	0,71	650 - 800	470
Larch	0,66	580 - 635	420
Pine	0,52	480 - 520	360
Spruce	0,45	420 - 450	330
Acacia	0,69	650 - 750	460
Elm	0,65	620 - 660	440
Aspen	0,48	460 - 550	350

What is the best firewood for fireboxes?

Oak firewood is considered the most optimal in terms of calorific value, followed by birch, aspen and pine.

Oak contains few resins, but releases a lot carbon monoxide. The tart aroma of burning oak logs tones the body.
Birch firewood burns for a long time, evenly, but has a lot of resinous substances and deposits soot in the chimney.
Softwoods are also used less frequently due to their high resin content.
It is not recommended to use poplar firewood, as it emits an unpleasant bitter odor and provides little heat.

It is best to use hardwood firewood, the specific gravity of which is high. It is desirable that the firewood be dry, not freshly cut. Recall that when buying wet firewood, you pay more for the weight, but you get less heat.

When working with lumber, it is often necessary to know what mass of wood. Let's figure out how much a cube of wood weighs and how to determine this value?

The mass of wood - why measure it?

First, let's figure out why this value is needed at all - mass of wood and how important this indicator is.
The weight of wood plays a big role in construction:
- Firstly, this indicator makes it possible to determine the weight finished construction whether its ceiling or foundation will withstand;
- secondly, a specific mass of lumber is necessary when determining the method of transportation, it helps to determine how much transport can move a particular amount of wood;
- thirdly, before buying a material, you need to figure out how much a cube of timber weighs, how much a cube of lining or boards weighs. All these materials are not sold individually, but in cubic meters. Therefore, knowing how to determine the weight of the material is necessary at least so that unscrupulous sellers cannot deceive you. Well, in order to provide yourself with the necessary amount of material, this also does not hurt. To find yourself in a situation where at the most inopportune moment you realize that there is not enough material is rather unpleasant, just like the situation when, after the completion of construction, it turns out that there is still a whole trailer of wood that is no longer needed;
- fourthly, such an indicator as mass of wood important in determining where to store the material. Knowing how much wood occupies, you can easily determine what size storage room you need.

How to determine the weight of a cube of wood?

The mass of wood depends on several parameters:

The type of tree. Wood species are divided into light ones weighing up to 500 kilograms (this includes conifers), medium - weight up to 650 kilograms (for example, birch or ash) and heavy - weight over 700 kilograms (the most popular representative is oak).

The humidity level is also divided into several levels: dry wood - humidity up to 15%, air-dry - humidity up to 20%, raw - up to 45%, and wet - humidity above 46%. That is, with different humidity, even the wood of one tree will have different mass and with the weight of different breeds will differ even with the same level of humidity.
The very concept of wood mass includes several measured parameters that are convenient to use in a particular case:
- The specific gravity of wood is a parameter that shows how the cube of wood and the cube of water correlate. The specific gravity of lumber is determined without taking into account moisture and wood species, that is, this indicator will be averaged for any tree. Specific gravity is used both to determine the actual cubic capacity of the wood and to determine the volume of the stocked board. It is convenient to use the specific weight of wood for companies involved in the transportation of material, in which case it is not necessary to measure the humidity and other values for each individual species, because sometimes several types of wood are transported, and their humidity can be completely different, calculating the total weight of such materials will take a lot of time , therefore it is easier to use a ready-made average value.
- void ratio - this indicator, which helps to determine the mass of stored lumber. Stored wood, especially if it is unfinished or has custom shape, forms voids between themselves, which significantly affect the determination of the total mass of such material. If the void factor is not taken into account in the calculations, only very approximate values \u200b\u200bcan be obtained. What is the formula for calculating the weight of wood, taking into account the coefficient of voidness? If we take all the stored material as 100%, then about 20% of them will occupy voids, respectively, the remaining 80% is wood. The void ratio will be 0.8. Let's say you have 10 cubic meters of space occupied by a stored board, multiply 10 by a factor of 0.8 and we get that the wood in the room is 8 cubic meters.

Reference values are on the Internet, and simply in everyday life there are certain persistent values \u200b\u200bof the weight of wood and wood products. This value is easy to use when buying. It is enough just to know the type of wood from which, for example, lining is made. You open the table and see how much one cubic meter of lining made of alder or oak timber weighs. This makes it very easy to check whether lumber sellers are deceiving you.

Volumetric weight of a cube of wood - an indicator of volumetric weight is often equal to the values of the density of wood. To determine it, a universal indicator of humidity is taken - 20% and a fixed density value is determined. All measured data are entered into special tables and are freely available on the Internet. Volumetric weight is also called GOST. The volumetric weight of wood uses the definitions of the parameters of both the raw board and the raw board. This value is very universal and allows you to compare the weight of different breeds, but subject to the same humidity.

Weight of a cubic meter of wood of different moisture content

Below is a table for your attention, which shows the weight values of wood of different species with different levels humidity.

Breed	Humidity, %
Breed	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
- 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
- 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

Irina Zheleznyak, Correspondent of the online publication "AtmWood. Wood-Industrial Bulletin"

For the manufacture of various building materials from wood (lining, board, slats, timber) material is used natural humidity. However, according to the requirements of GOST and building codes, raw wood floor boards must be dried before laying. From this indicator depends on how much the cube of the board of natural humidity weighs. Although the price of the material is charged for its volume, the weight of the board of natural moisture is important when transporting products. We will tell you how much a cube of natural moisture boards of different breeds weighs.

The concept of material moisture

Before you tell how much a natural moisture edged board and other lumber weigh, you need to understand the basic concepts. For the manufacture of grooved, terraced, planed and edged boards, different breeds tree. Each breed has its own specific hygroscopicity, that is, the ability to absorb moisture from the air.

Depending on the absorption of moisture, porosity and the structure of cell membranes, each type of wood has its own absolute humidity. Maximum value this indicator is 30.

In addition, a natural moisture board can absorb water in direct contact with it during precipitation or when the room is flooded. Dampness in the room is also the reason wood absorbs moisture. If the surrounding air becomes very dry, it releases moisture.

Important! Most often, moisture loss occurs through the ends of the product.

The normal process of absorbing and releasing moisture into wood is called "breathing". Equilibrium moisture is the state in which there is a balance of water between environment and interior wood.

The indicator of natural saturation with water depends on the location of the fibers in the structure. Moisture evaporates faster in the longitudinal direction of the fibers, and not in the transverse direction. That is why the floor from the board of natural moisture quickly releases moisture at the ends of the floorboards.

To understand what is batten normal humidity, you need to understand the concept of absolute and relative humidity:

Relative saturation moisture is the percentage of its mass in wood to the mass of a wet product.
Absolute indicator always more than relative. This is a percentage of the mass of moisture in wood to the weight of ordinary dry material.

Important! Since the hygroscopic intracellular fluid collects in the cell walls, it is more difficult to remove. In this regard, hygroscopic moisture has a greater effect on the geometry of the board, its weight and characteristics.

The weight of a natural moisture cut board also depends on the unbound free liquid in the material, which collects in the intercellular spaces and inside the cells. Such moisture evaporates quickly and does not affect the performance of the product.

Natural moisture refers to the moisture content of freshly sawn wood that has not been dried. This non-standardized indicator can be in the range of 30-80 percent. The weight of 1 m3 of natural moisture cut board depends on:

conditions in which the tree grows;
the season when the split was made (winter wood is less saturated with moisture than the one that was cut in the summer season).

The dependence of the weight of the board on moisture

If you need a board of natural moisture, the price depends on the weight of the cube of the material and its saturation with moisture:

semi-dry products have a humidity of 18 to 23 percent;
a raw product with a moisture content of more than 23% is the cheapest - from $ 30 per cubic meter;
dry edged board with humidity in the range of 12-18 percent costs $40-50 per cubic meter;
dry lumber with a humidity of 6-12 percent are the most expensive - from $ 60 per m³.

Depending on the dampness, the weight of the material also changes. For example, a cube of wet oak floorboards weighs 990 kg. If the material is dried to a moisture content of 10%, then the mass of the cube will decrease to 0.67 tons. But the price for dried lumber will increase.

The increase in price depending on the saturation with moisture is justified by the fact that the characteristics of the product also increase:

dried wood has dimensional stability;
it is resistant to decay;
the material is durable and flexible;
the tree is quickly and easily processed;
provides a strong adhesive fixation;
the product will last longer.

Attention! Wet wood is prone to mold, rot and warping. Ideally, if the moisture content of the lumber is brought to the point at which the shrinkage and swelling of the wood stop. That is why the cost of such products is the highest.

How much does a cube of boards from different breeds weigh?

The weight of a cube of material is directly related to the type of wood from which it is made:

An oak board of natural moisture content weighs 990 c/m³. A cube of dried wood weighs 670 centners.
Wet pine floorboards weigh 820 kg / cu. The dried elements have a weight of 470 c/m³.
Cube boards from wet spruce wood weighs 760 q, and dried board - 420 q.
Wet larch products have a weight of 940 kg / cu. A cube of dry larch weighs 630 kg.
birch lumber undried weigh 870 centners / m³, and dry - 600 centners / cu.
Aspen floorboards from wet wood - 760 centners / cubic meter, and dried - 470 centners.
Alder wood cube after saw cut, it has a weight of 810 centners, and the dried material - 490 centners.

Why is it necessary to know the weight of a cubic meter of wood?

Since the manufacturer charges the price for lumber depending on the type of wood, moisture content and volume, the weight of the material is not taken into account. This indicator will be needed when transporting lumber, since the choice depends on it. vehicle and the cost of transportation.

Also, the weight of wood is taken into account when calculating the loads on building construction. As a rule, an ordinary consumer does not need such a calculation. It is made by designers and designers at the stage of project development.

Artificial and natural drying

The natural drying of lumber is very slow and stretches for long time. However, such a drying process is considered the most gentle, since cracks and other deformation defects do not appear in the wood. With aggressive chamber drying, there is a high probability of cracking and deformation of the lumber.

Important! Natural drying is carried out in a special well-ventilated place, which is reliably protected from atmospheric moisture and direct sunlight.

Humidity of a freshly cut tree reaches 50-80%. With natural drying, this figure drops to 18-22 percent. This drying method is the easiest to organize, since it does not require the use of special equipment and adherence to a certain temperature regime. disadvantages natural drying- the duration of the process and low intensity.

Artificial drying in chambers proceeds much faster. At the same time, the humidity index decreases to 10-18 percent. During the drying process, you can adjust the temperature and control the whole process. Products placed in stacks are placed in the chambers, each of which contains sawn timber of the same thickness and breed.

Advantages of artificial drying:

protection against mold and rot;
you can dry wood treated with special protective compounds;
drying speed (usually it takes a week).

The wood has been used in construction works ah from a long time ago. Of course, because this material is still very popular due to the presence of excellent specifications. Wood itself is natural material structured type, consisting of wood cells and pericellular voids, which in turn does not guarantee at all 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 counting the right amount this material and such parameters as: the weight of the wood as a whole and the weight of the cube of wood.

The weight of wood species depending on the type in the table

wood species	Humidity percentage, %
wood species	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
Norway 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
Scotch 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. On the weight of m3 of wood, the density of the material is of particular importance, respectively, for right decision of the questions posed, it is necessary to determine the value of the density. There are two types of density:

Specific gravity (density of the wood substance)

Volumetric weight (density of a structured physical body)

The density of the wood itself is quite easy to determine under normal conditions. To do this, just weigh a piece of wood and measure its volume. Process the obtained data with standard arithmetic operations according to the following formula: Y \u003d M / O, where Y is the specific weight of the tree, M is the mass of wood, O is the volume occupied.

Table of volumetric weight of 1m3 of wood depending on humidity.

The density of the wood substance, as already mentioned, is a constant. However, wood has a multicellular fibrous structure. complex type. The walls of the wood substance play the role of a frame in the wood structure. Accordingly, for each breed and species of trees, the cell structures, shapes and sizes of cells vary, as a result of which the specific gravity of the tree will be different, as well as the different weight m3 of the tree.

Also, humidity plays an important role in changing the specific gravity of wood. Due to the structure of this material, with an increase in humidity, the density of wood also increases. However, this rule does not apply to the density of the wood substance.

Below is the specific gravity of wood. The table is compiled depending on the moisture content of the material and is calculated such an indicator as the weight of 1 m3 of wood.

When organizing the transportation of timber, the density of a tree is an important indicator in the selection of a timber carrier and calculation of the cost of transportation. This will help to avoid overloading, which will accordingly reduce the penalty.

The density of the material is of particular importance to the weight of m3 of wood, respectively, for the correct solution of the questions posed, it is necessary to determine the value of the density. There are two types of density: volume weight(density of a structured physical body) and specific gravity(density of the wood substance).

Volumetric weight of wood

The weight of a cubic meter of wood depends on the type of wood and humidity.

Calculator for calculating the volumetric weight of a tree.

Tree White Acacia Birch Beech Elm Oak Hornbeam Spruce Norway Maple Linden Larch Alder Walnut Aspen Siberian Fir Caucasian Fir Scots Pine Cedar Pine Poplar Ash

Volume, m3:

Specific gravity of wood

Wood substance is 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 impossible under normal conditions. For each wood of all types and species of trees, this value is a constant and is 1540 kg/m3. However, wood has a multicellular fibrous structure of a complex type. The walls of the wood substance play the role of a frame in the wood structure. Accordingly, for each breed and species of trees, the cell structures, shapes and sizes of cells vary, as a result of which the specific gravity of the tree will be different, as well as the different weight m3 of the tree.

Table of wood density of different moisture content (kg/m3).

№	wood species	Humidity percentage, %
№	wood species	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	Norway 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	Scotch 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