One of the tasks when developing a draft technological regulation for the process of handling construction and demolition waste is to calculate the mass and volume of logging residues formed during the cutting down of green spaces (tree removal) in the construction or demolition zone.
The official methodology for calculating the mass and volume of logging residues for these purposes in Russian Federation No. The initial data for such calculations is information about the trees being cut down (species, height and thickness at a height of 1.3 m) and shrubs (young trees), given in the count sheet from the composition project documentation to the construction (demolition) site.
This article presents a method for calculating the mass and volume of logging residues developed in our company. As the basis for its development, tabular data from the All-Union standards for forest taxation, approved by Order of the USSR State Forestry Committee of February 28, 1989 No. 38, was used.
1) Data from Table 17 “Trunk volumes (in bark) in young trees by height and diameter at a height of 1.3 m” - to determine the volume of trunks of young growth and shrubs. As a result of processing the given data to determine the average ratio between the diameter (D), height (h) and volume (V) of one trunk, the calculated shape coefficient (Kp from Table 1) was determined, which with an accuracy of +/- 10% allows you to determine the volume of the trunk by formula Vst=Кn*h*пD2/4.
2) Data from tables 18 and 19 “Volumes of trunks (in bark) of tree species by height and diameter at a height of 1.3 m with an average shape coefficient” - to determine the volume of trunks of various tree species. As a result of processing the given data to determine the average ratio between the diameter (D), height (h) and volume (Vst) of one trunk, calculated coefficients were determined for some of the tree species listed in the table, which with an accuracy of +/-10% allows us to determine the volume of the trunk according to the formula Vst=Кn*h*пD2/4. The calculated form factors are given in Table 1
3) Data from table 185 “Weight of 1 cubic meter. m and volume 1 t of wood different breeds" - to determine the mass of wood, the mass values of one cubic meter of the corresponding wood species from the column “freshly cut” were used, or from the column “dry” - for dead wood.
4) Data from table 206 “Volume of bark, twigs, stumps and roots” to determine the volume of twigs and branches, as well as stumps and roots as a percentage of the volume of trunks. For the calculation, average values from the interval given in the tables were used. The volume of twigs and branches is 7% of the volume of trunks, the volume of stumps and roots is 23% of the volume of trunks.
5) Data from Table 187 “Fully wooded brushwood and cottonwood coefficients” - to determine the folded volume of twigs and branches from the full wooded volume using a conversion factor of 10.
FKKO-2014 contains codes for the following waste:
1 52 110 01 21 5 Waste of twigs, branches, tips from logging
1 52 110 02 21 5 Stump uprooting waste
1 54 110 01 21 5 Low-value wood waste (brushwood, dead wood, trunk fragments).
Therefore, the calculation of the mass and volume of logging residues must be calculated by type of waste:
- trunks of trees, young growth and shrubs cut down according to the accounting list can be classified as waste of low-value wood (brushwood, dead wood, fragments of trunks);
- twigs and branches - to waste of twigs, branches, tips from logging;
- stumps and roots - waste from stump uprooting.
For the technological regulations of the Process of handling construction and demolition waste, it is necessary to calculate the mass of waste, but for temporary storage in storage bins and their removal from the construction site, it is necessary to estimate the volume of logging residues, and in the storage volume.
The calculation is made using the Excel application. An example of an Excel page table header is shown in Table 2.
The calculation was carried out in the following order:
1) Filling out the initial data according to the accounting sheet;
column 2 - line number of the accounting sheet;
column 3 - wood type;
column 4 - number of trees;
column 5 - minimum trunk diameter from the interval specified in the counting sheet;
column 6 - the only value of the trunk diameter indicated in the counting sheet;
column 7 - maximum trunk diameter from the interval specified in the counting sheet;
Column 8 - minimum trunk height from the interval specified in the counting sheet;
column 9 is the only value of the trunk height indicated in the counting sheet;
column 10 - maximum trunk height from the interval specified in the counting sheet;
column 11 - additional number of trunks - if in the column “characteristics of the state of green spaces” n trunks for one tree are indicated, then in column 11 it is indicated (<значение графы 11>= (n-1)*<значение графы 4>.
2) Calculation of the average value of the trunk diameter if there is an interval:<среднее значение диаметра ствола (графа 6)> = (<значение минимального диаметра (графа 5)>+<максимальное значение диметра (графа 7)>)/2;
3) Determination of the volume of one trunk<объем ствола (графа 12)>is made according to Vst = Kn*h*pD2/4, where Kn is the corresponding shape coefficient from Table 1, D is the average trunk diameter, h is the average trunk height. Calculation of the volume of one trunk:<объем ствола в куб.м (графа 12)>=Кn* π*(<диаметр ствола в см (графа 6>/100)* (<диаметр ствола в см (графа 6>/100)*< высота ствола в м (графа 9)>/ 4);
4) Calculation of the dense measure of trunk volume Vpl=Vst*nst, where nst is the total number of trunks:<плотная мера объема стволов (графа 13)> = <средний объем ствола в куб.м (графа 12)>*(<число деревьев или кустов (графа 4)>+<число дополнительных стволов (графы 11)>). For one bush, the number of additional trunks is taken to be 5;
5) Calculation of folding measures (when storing or transporting, it is necessary to take into account the average volume of space occupied by tree trunks or bushes:<складочная мера объема стволов (графа 14)>= <плотная мера объема стволов (графа 13)>*4/p;
6) Calculation of the volume of twigs and branches depending on the volume of the trunk is carried out in accordance with paragraph d) of this article:<объем сучьев и ветвей в плотной мере (графа 16)> = <плотная мера объема стволов (графа 13)> *<переводной коэффициент (графа 15=0,007)>. In folding measure - according to paragraph e) of this article:<объем сучьев и ветвей в складочной мере (графа 18)> = <объем сучьев и ветвей в плотной мере (графа 16)>*<переводной коэффициент (графа 17=10)>;
7) Calculation of the volume of stumps and roots from the volume of the trunk is carried out in accordance with paragraph d) of this article:<объем пней и корней в плотной мере (графа 20)> = < плотная мера объема стволов (графа 13)>*<переводной коэффициент (графа 19=0,23)>. In the fold measure, the volume of stumps and roots is assumed to be double volume:<объем пней и корней в складочной мере (графа 21)> =<объем пней и корней в плотной мере (графа 20)>*2.
8) Calculation of the total volume of wood in a dense measure:<полный объем (графа 22)> = <объем стволов в плотной мере (графа 13)>+<объем сучьев и ветвей в плотной мере (графа 16)>+< объем пней и корней в плотной мере (графа 20)>;
9) Calculation of the total volume of wood in a folded measure (this indicator most objectively allows us to assess the need for the capacity of bodies (containers) Vehicle for removal of logging residues):<полный объем древесины в складочной мере (графа 23)> = <складочная мера объема стволов (графа 14)>+ <объем сучьев и ветвей в складочной мере (графа 18)>+ <объем пней и корней в складочной мере (графа 21)>
10) The volumetric weight of wood in a dense measure (density in t/m3) is recorded in column 24 in accordance with paragraph c) of this article, for species not listed in table 185 - in accordance with Appendix 3 to SNiP II-25-80 (Density of wood and plywood ).
11) Calculation of the weight of the trunks:<вес стволов (графа 22)> = <объем стволов в плотной мере (графа 13)>*<volume weight wood (column 21)>;
12) Calculation of the weight of twigs and branches:<вес сучьев и ветвей (графа 26)> = <объем сучьев и ветвей в плотной мере (графа 16)>*< объемный вес древесины (графа 24)>;
13) Calculation of the weight of stumps and roots:<вес пней и корней (графа 27)> = <объем пней и корней в плотной мере (графа 20)>*< объемный вес древесины (графа 24)>;
14) Total weight of removed waste (logging residues):<вес вывозимого отхода (графа 28)> = <вес стволов (графа 25)> + <вес сучьев и ветвей (графа 26)>+<вес пней и корней (графа 27)>
Thus, the proposed methodology allows you to calculate the volume (both full and folded) and weight of logging residues, differentiated by type of waste based on the initial data of the counting sheet, as well as estimate the required volume of storage bins or vehicle bodies and the number of vehicle trips for their removal.
WEIGHT OF 1 CUBIC METER (VOLUMERIUM WEIGHT) OF BEAM, BOARDS AND LOODS
The weight of lumber (timbers, boards, logs), moldings (linings, platbands, baseboards, etc.) and other wood products depends mainly on the moisture content of the wood and its species.The table shows the weight of 1 cubic meter of wood (volume weight) depending on the type of wood and its moisture content.
Weight table 1 cu. m (volume weight) timber, boards, linings made of wood of various species and humidity
Depending on the moisture content, measured as a percentage of the mass of water contained in the 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 for a long time in a warm, dry room;
Air-dry wood (humidity 19-23%) is wood with equilibrium moisture content, when the moisture content of the wood itself is balanced with the humidity of the surrounding air. This level of humidity is achieved when long-term storage wood in natural conditions, i.e. without the use of special drying technologies;
Raw wood(humidity 24-45%) - this is wood in the process of drying from a freshly cut state to equilibrium;
Freshly cut and wet wood (moisture content greater than 45%) is wood that has been recently cut or has been in water for a long time.
WEIGHT OF ONE BEAM, ONE EDGED AND FLOORBOARD, LINING
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 data for the wood most used in construction - pine with damp moisture for timber and edged boards and air-dry moisture for floorboards and lining.Weight table for one beam, one board and lining
NUMBER OF BOOTS, BOARDS AND LINING IN 1 CUBIC. 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 quantity of lumber in 1 kb. m are presented in the table. 3..Measurement and accounting of felled trees
Each tree can be divided into three parts: trunk, branches and roots. The ratio of these parts to each other in terms of mass varies depending on the breed, age and growing conditions.
Rice. 6. Shape of trees (I) and cross-section of the trunk (II): 1 - tree grown in a dense forest; 2 - in a forest of medium density; 3 - in a sparse forest; AB - largest diameter; CD - smallest
But, as a rule, the stem part makes up the main wood mass, which increases with age.
Numerous observations have shown that in mature, closed stands the mass of stem wood is 60-85%, branches 5-25 and roots 5-30% of the total mass of the tree.
Table 1
The density of the tree stand has a very large influence on this ratio. The trunks in dense stands are taller and in shape in the first half of the tree they are close to a cylinder, in rare ones they are stunted and have a more conical shape, and the crowns are usually large and spreading (Fig. 6). For example, in oak trees grown in the wild in the form of lighthouses, the mass of branches at the age of 50-60 years reaches 50% or more. Best development has a trunk of coniferous trees: spruce, fir, larch and pine.
Taxation characteristics of a tree trunk.
At the bottom the trunk resembles a cylinder, at the top it resembles a cone. To determine the volume of a cylinder and cone, you need to know their height and base area, which can be calculated from its diameter. To determine the volume of a trunk, you need to know its shape, height (length) and thickness (diameter). These elements are the main taxation characteristics of the trunk, and all the others are derived from them. In cross-section, a tree never gives a circle, but only approaches it, but for practical purposes, without any special errors, it is accepted as a circle. It must be remembered that the diameter of the tree must always be measured very carefully, taking it as the average of two mutually perpendicular diameters or from the largest and smallest (see Fig. 6). When determining the height of a felled trunk, it is practically not the length of its axis that is measured, but the curve forming the trunk, since the resulting error is extremely negligible.
Determination of trunk volume.
A felled tree, cleared of twigs and branches, forms a whip or trunk. The volume of a trunk is always less than the volume of a cylinder and greater than the volume of a cone of the same height and base area. By gradually reducing the diameter of the cylinder, you can find one at which its volume is equal to the volume of a tree trunk of the same height. Numerous studies have established that this diameter is approximately the diameter of the middle of the trunk. Therefore, to determine the volume of the trunk, you need to measure its length with a tape measure or other measuring instrument and the diameter in the middle with a measuring fork, then, using the measured diameter, calculate the area of the circle and multiply it by the length of the trunk. As a result, we obtain the volume of the measured trunk.
In table 1 shows data for determining the volume of the trunk based on the measured median diameter and height (length). In table 1 shows the most common heights and median diameters of trunks. It can be extended both in length and in diameter. This kind of table is often called cylinder volume tables. Using the table is very simple.
Example. It is required to determine the volume of two trunks with a length of 21 and 11 m with a median diameter of 17 and 12 cm, respectively. To determine the volume of the first trunk according to the table. 1 we find in the first column on the left the number 21 m and on this line a column with a diameter of 17 cm; where they intersect is the number 0.4767. This means that the required volume is 0.4767 m3. The volume of the second trunk is found at the intersection of line 11 and column 12 cm; it is equal to 0.1244 m3.
-It should be noted that when determining the volume by the median diameter, significant errors are possible and in most cases towards an underestimation of the actual volume (sometimes over 10%), but the calculations are made easily and quickly and are quite acceptable for practical purposes. If the volume of the trunk needs to be calculated with greater accuracy, then it is divided into parts and for each of them the volume is determined by the median diameter and length. The shorter these parts are and the more they are cut out of the trunk, the more accurate the result can be obtained based on the total volume. Usually the trunk is divided into 2 sections (Fig. 7). The work is performed as follows. The trunk is marked using a tape measure on the 2nd segments with small notches in their middles, then in the places of the notches, the diameters are measured with a measuring fork and using the table. 1 and 2 find the volumes of all parts, the sum of which gives the volume of the trunk, excluding the top.
Rice. 7. Splitting the tree into 2nd sections
In table Figure 2 shows the volumes of the 2nd segments along the median diameter. The volume of a peak less than 2 m long is usually so small that it is practically not taken into account. The volume of the vertex is calculated using the formula for the volume of a cone - multiplying the area of the base by */3 of the height, i.e. the area of the base should be multiplied by the length and the resulting product divided by three. In table Figure 3 shows data for determining the required volume based on the measured diameter of the base of the apex and its length.
Example. You need to find the volume of a trunk 22 m long. The median diameters of the 2 segments are equal: the first (1 m from the bottom segment) 41; second (3 m) 37; third (5 m) 34; fourth (7 m) 31; fifth (9 m) 29; sixth (11 m) 27; the seventh (13 mU 24; the eighth (15 m) 21; the ninth (17 m) 17 and the tenth (19 m) 12 cm. The diameter of the base of the top (2 m long) is 8 cm.
It varies widely even for one type of wood. The values of the density (specific gravity) of wood are generalized figures. The practical value of wood density differs from the average table value given and this is not an error.
Table of density (specific gravity) of wood
depending on the type of wood
| "Handbook of masses of aviation materials" ed. "Mechanical Engineering" Moscow 1975 | Kolominova M.V., Guidelines for students of specialty 250401 “Forest Engineering”, Ukhta USTU 2010 | |||
| Wood species | Density wood, (kg/m3) |
Limit density wood, (kg/m3) |
Density wood, (kg/m3) |
Limit density wood, (kg/m3) |
| Ebony (black) |
1260 | 1260 | --- | --- |
| Backout (iron) |
1250 | 1170-1390 | 1300 | --- |
| Oak | 810 | 690-1030 | 655 | 570-690 |
| Red tree | 800 | 560-1060 | --- | --- |
| Ash | 750 | 520-950 | 650 | 560-680 |
| Rowan (tree) | 730 | 690-890 | --- | --- |
| Apple tree | 720 | 660-840 | --- | --- |
| Beech | 680 | 620-820 | 650 | 560-680 |
| Acacia | 670 | 580-850 | 770 | 650-800 |
| Elm | 660 | 560-820 | 620 | 535-650 |
| Hornbeam | --- | --- | 760 | 740-795 |
| Larch | 635 | 540-665 | 635 | 540-665 |
| Maple | 650 | 530-810 | 655 | 570-690 |
| Birch | 650 | 510-770 | 620 | 520-640 |
| Pear | 650 | 610-730 | 670 | 585-710 |
| Chestnut | 650 | 600-720 | --- | --- |
| Cedar | 570 | 560-580 | 405 | 360-435 |
| Pine | 520 | 310-760 | 480 | 415-505 |
| Linden | 510 | 440-800 | 470 | 410-495 |
| Alder | 500 | 470-580 | 495 | 430-525 |
| Aspen | 470 | 460-550 | 465 | 400-495 |
| Willow | 490 | 460-590 | 425 | 380-455 |
| Spruce | 450 | 370-750 | 420 | 365-445 |
| Willow | 450 | 420-500 | --- | --- |
| Hazelnut | 430 | 420-450 | --- | --- |
| Walnut | --- | --- | 560 | 490-590 |
| Fir | 410 | 350-600 | 350 | 310-375 |
| Bamboo | 400 | 395-405 | --- | --- |
| Poplar | 400 | 390-590 | 425 | 375-455 |
- The table shows the density of wood at a humidity of 12%.
- The table indicators are taken from the “Handbook of Masses of Aviation Materials” ed. "Mechanical Engineering" Moscow 1975
- Corrected on March 31, 2014, according to the method:
Kolominova M.V., Physical properties of wood: guidelines for students of specialty 250401 “Forest Engineering”, Ukhta: USTU, 2010
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It is generally accepted to indicate the density (specific gravity) of wood depending on the type of wood. The indicator is taken to be the average value of the specific gravity, obtained by summarizing the results of repeated practical measurements. In fact, two wood density tables are published here, taken from completely different sources. A small difference in the indicators clearly indicates the variability of the density (specific gravity) of wood. When analyzing the wood density values from the table above, it is worth paying attention to the differences between the indicators in the aviation reference book and the university manual. For objectivity, the value of wood density from both documents is given. With the right for the reader to choose the priority of the importance of the original source.
Particularly surprising is the tabular density value larches- 540-665 kg/m3. Some online sources indicate the density of larch as 1450 kg/m3. It is not clear who to believe, which once again proves the uncertainty and unknown nature of the topic being raised. Larch is a fairly heavy material, but not so heavy as to sink like a stone in water.
The influence of humidity on the specific gravity of wood
Specific gravity of driftwood
It is noteworthy that with an increase in wood moisture content, the dependence of the specific gravity of this material on the type of wood decreases. The specific gravity of driftwood (humidity 75-85%) practically does not depend on the type of wood and is approximately 920-970 kg/m3. This phenomenon is explained quite simply. The voids and pores in wood are filled with water, the density (specific gravity) of which is much higher than the density of the displaced air. In terms of its value, the density of water approaches the density of , the specific gravity of which practically does not depend on the type of wood. Thus, the specific gravity of pieces of wood soggy in water is less dependent on its species than in the case of dry samples. At this point it is worth remembering that for wood there is a division of classical physical concepts. (cm. )
Wood Density Groups
Conventionally, all tree species are divided into three groups
(according to the density of its wood, at a humidity of 12%):
- Low density rocks(up to 540 kg/m3) - spruce, pine, fir, cedar, juniper, poplar, linden, willow, aspen, black and white alder, chestnut, white, gray and Manchurian walnut, Amur velvet;
- Medium density rocks(550-740 kg/m3) - larch, yew, silver birch, downy, black and yellow, eastern and European beech, elm, pear, summer oak, eastern, swamp, Mongolian, elm, elm, maple, hazel, walnut , plane tree, rowan, persimmon, apple tree, common ash and Manchurian;
- Breeds high density (750 kg/m3 and above) - white and sand acacia, iron birch, Caspian honey locust, white hickory, hornbeam, chestnut-leaved and Araxinian oak, ironwood, boxwood, pistachio, hop hornbeam.
Density of wood and its calorific value
The density (specific gravity) of wood is the main indicator of its heating properties. energy value- . The dependence here is direct. The higher the density of the wood structure of a tree species, the more combustible wood substance it contains and the hotter such trees are.
The wood was used in construction work ah since ancient times. Of course, this material is still very popular due to the presence of excellent technical characteristics. Wood itself is a natural material of a structured type, consisting of wood cells and pericellular voids, which in turn does not at all 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 this material and such parameters as: the weight of the wood as a whole and the weight of a cube of wood.
| Wood species | Humidity percentage, % | ||||||||||
| 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 |
| Scots 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, wood needs to be measured differently. The density of the material has a special significance on the weight of m3 of wood; accordingly, in order to correctly solve the questions posed, it is necessary to determine the value of the density. There are two types of density:
Specific gravity (density of wood substance)
Volumetric weight (density of a structured physical body)
Wood substance is a mass of solid wood materials without natural voids. This type 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 quite easy to determine under normal conditions. To do this, just weigh a piece of wood and measure its volume. Process the obtained data using standard arithmetic operations using the following formula: Y = M/O, where Y is the specific gravity of the tree, M is the mass of the wood, O is the occupied volume.
Table of volumetric weight of 1m3 of wood depending on humidity.
The density of wood matter, as already said, is a constant. However, wood has a multicellular fibrous structure of a complex type. Walls made of wood substance play the role of a frame in the structure of wood. Accordingly, for each tree species and 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 the different weight of m3 of the tree.
Also, humidity plays a big 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 wood substances.
Below is the specific gravity of wood. The table is compiled depending on the moisture content of the material and is calculated using an indicator such as the weight of 1m3 of wood.
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