Edged board is one of the most common lumber in construction. It is used for outdoor work, during construction wooden houses, interior decoration, manufacturing wooden fences. The board is sawn from logs and additionally sawed along the edges. This gives the lumber not only a marketable appearance, but also protects it from various pests. As a rule, the width of an edged board is twice its thickness.
The greatest demand in construction is for boards made from coniferous wood - spruce and pine, Siberian larch. For the production of furniture, more expensive and durable types of wood are used - oak, alder, ash.
The quality and cost of lumber depends on many characteristics: the type of wood, its moisture content, processing and sawing technology. Therefore, it is important to correctly calculate the yield of edged lumber in production.
depends on many factors: the specification, the grade of the board, the diameter of the saw log.
For example, from round timber In coniferous species, the yield of edged lumber on band sawmills is usually 55 - 60%. On disk sawmills this percentage increases to 70-75%.
The yield of edged boards from round deciduous wood (aspen, birch, linden) is always very low for all types of sawmills. Approximately 35-40%. This is due to the curvature of hardwood logs. You can increase the percentage output only by setting optional equipment- multi-rip, edge-edging and slab machines. The yield, in this case, will increase by about 20%.
Generally? prices for lumber fluctuate greatly, and many lumber companies provide edged boards at a price significantly lower than the market price. However, before you buy lumber from such sellers, you need to think about what pitfalls may be hidden here. Often the cost of boards is reduced due to the low quality of lumber. Thus, it is most appropriate to purchase edged boards from those companies for which selling wood is not a new thing.

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TIMBER YIELD BASED ON FIR ROUND TIMBER VOLUME TABLES

Koptev Artem Sergeevich 1, Weiss Andrey Andreevich 2
1 Federal State Budgetary Educational Institution of Higher Education "Siberian State Technological University", Bachelor in Forestry
2 Federal State Budgetary Educational Institution of Higher Education "Siberian State Technological University", Doctor of Agricultural Sciences, Associate Professor of the Department of Forest Taxation, Forest Management and Geodesy

OUT OF LUMBER BASED ON THE TABLES OF VOLUMES OF ROUNDWOOD FIR

Koptev Artem Sergeevich 1, Weis Andrey Andreevich 2
1 Siberian state technological university, bachelor in "Forestry business"
2 Siberian state technological university, doctor of agricultural sciences, assistant professor of forest inventory, forest management and geodesy

Back in the second half of the twentieth century, in forest taxation it was considered advisable to determine volumes for practical purposes using special tables. Of all the tables compiled, the tables of A.A. Kründer, common for all species, without taking into account the location of the harvested assortments on the trunks, have found the greatest use in our country. These tables were later recalculated by G.M. Tursky into the metric system, supplemented by N.P. Anuchin and approved as GOST 2708-44.

Other tables were also used in practice before. For example, Provatorov’s table, which was compiled without any basic taxation material, purely mathematically calculated the volumes of logs, assuming one constant run for logs of all species and categories.

Klimashevsky’s tables, as well as Provatorov’s tables, were characterized by the fact that the volumes of logs were calculated purely mathematically, assuming their division into five classes, respectively, with a run of 1/8, 1/4, 3/8, 1/3 and 5/ 8 tops by a fathom.

Tables of Tour, Arnold, Toursky, Rudzsky - were characterized by compiling the volume of logs based on numerous observations of the run-off and volume of logs different breeds, and the possibility of providing one general table for logs of all classes and species was recognized.

However, these tables had certain disadvantages. For example, the tables of Tour, Arnold, Tursky, Rudzki were not adapted to the normal taxation of logs separately and acceptable determined the volume only with joint taxation more logs when we should expect a smoothing out of the extremes in the average result.

Also, the tables did not provide for the fact that the accuracy of estimating logs is influenced by the degree of granularity of thickness steps for log diameters and total length logs When taking a very large step for log diameters of 4 cm, tables for single logs or for a small number of them should give large errors due to the rounding of diameters.

In modern forestry practice, the relationship between the characteristics of the entire forest stand and the parameters of individual trees in this tree stand is known. For example, according to research, the density of the grown tree stand affects the quality of the timber. To improve the quality of timber, a greater density of the tree stand is needed in the early phase of rotation to reduce the growth of branches in the lower part of the trunk, their accelerated death and self-cleaning of the trunks. In the late phase of cutting rotation, a relatively sparse tree stand is desirable to clear branches and accelerate the overgrowth of nodes. As is known, the greater the density, the smaller the runoff and vice versa, the lower the density, the greater the runoff, which in turn, as is already clear from the presented material, greatly influences the accuracy of determining the volume of assortments.

It is also necessary to take into account the influence of felling on the characteristics of the renewed subsequent forest stand. It is known that thinning contributed to a significant increase in trunk diameter at breast level, height growth, crown-to-trunk size ratio, crown width, but led to a decrease in trunk height to diameter at breast height. The trunk run-off also increased significantly, and therefore the determination of the wood supply turned out to be overestimated by 2-15%, especially for trees in thinned stands.

International trade in timber products is developing very dynamically. According to FAO, global roundwood exports have increased by 8 million m 3 over the past decade in quantitative terms. This was facilitated by the constant growth of global consumption of lumber in various sectors of the economy and the increasing importance of wood as a natural, environmentally friendly universal material. International trade in unprocessed wood today is developing in the context of growing volumes of its consumption. The leading exporters of round timber in the world are Russia, New Zealand, USA, and the main importers of unprocessed wood are China, Austria, and Germany. The main factor in the growth of international trade volumes is currently the growth in wood consumption in the world, and this trend in the world market will continue in the next few years.

Experimental studies. The research was carried out in the Biryusinsky district forestry of the educational and experimental forestry enterprise of Siberian State Technical University. Measurements of Siberian fir round timber were taken at the lower warehouse. Subsequently, the volumes of round timber were established different ways. The yield of cubic meters of lumber from a log was determined using Table 1 below.

Table 1 - Determination of lumber yield

Note: When the roundwood grade increases to 1, the lumber yield standard increases by 3%. When the grade of roundwood is reduced to grade 3, the lumber yield standard is reduced by 2%, to grade 4 – by 7%. With a mixed supply of large and medium logs, the lumber yield standard is taken as the arithmetic mean between medium and large logs.

As can be seen from the table, approximately 50% of the volume of the entire log is lumber. It is worth noting that coniferous trees have a higher lumber yield than deciduous trees.

Below is a table showing how many cubic meters of lumber, wood waste and sawdust come out when using the calculation results using the truncated cone formula and tabular data (Table 2), as well as using the median section formula (Table 3). The volumes were found for one log and for one hundred logs. The difference between the two lumber yields is also shown as a percentage. The yield of lumber obtained by calculation using the truncated cone formula for the first table and the median section formula for the second is taken as 100%.

Additionally, the cost of lumber obtained from 100 logs was calculated, the volume of which was determined from tabular data and the truncated cone formula (Table 3), as well as from tabular data and the formula for the median section (Table 4). In addition, the difference between the costs of lumber has been established.

Conclusions. A comparative analysis showed that standard values ​​in most cases underestimate the volume of logs by thickness level in comparison with the truncated cone formula (-33.2-+6.4%). In the thicker part of the logs, this difference stabilizes and is about 10%. At the same time, in relation to the formula for the median section, the tabulated values ​​of fir logs in most cases overestimate the actual volume of round timber. In value terms, for 100 logs the difference can be (36 cm step) up to 60,000 rubles.

Thus, the use of the truncated cone formula makes it possible to significantly reduce the error in determining the volume of fir logs in relation to the local East Sayan mountain taiga region.

Table 2 - Lumber output

Continuation of Table 2

Table 3 - Lumber output

Table 4 - Cost of lumber

1. “European Agreement concerning the International Carriage of Dangerous Goods by Road” (ADR/ADR) (Concluded in Geneva on September 30, 1957).
2. Orlov M.M. Taxation of various assortments of industrial wood // Forest taxation. 1932. Chapter 14. With. 74-75.
3. Sawn timber properties of Scots pine affected by initial stand density, Thinning and pruning: A simulation based approach: Dokl. / IkonenVeli-Pekka, Kellomoki Seppo, Peltola Heli // Silva fenn. 2009. 43. No. 3. p. 411-431.
4. Long-term effects of precommercial thinning on the stem dimensions, form and branch characteristics of red spruce and balsam fir crop trees in Maine, USA: Report_ / Weiskittel Aaron R., Kenefic Laura S,. Seymour Robert S., Phillips Leah M. // Silva fenn. 2009. 43. No. 3. p. 397-409.
5. Varivodina I.N. , Kuznetsova E.V. , Perelygina O.G. Features of determining the volume of round timber in Russia and abroad // EUROPEAN STUDENT SCIENTIFIC JOURNAL. 2014. No. 1.

Lumber is obtained by cutting logs (blanks). In essence, this is lumber of a certain size with two plane-parallel sides (faces). Sawing can be either radial or tangential.

In Fig. 1 presents various types of lumber - from plates to edged boards.

Figure 1. Types of lumber: a - plate; b - two-roll beam; c - not edged board; g- quarter; d - four-edged timber with wane; e - semi-edged board with wane; g - clean-edged timber; h - croaker; and - edged board; k - planed tongue and groove boards; 1- face; 2 - edge; 3 - rib; 4 - end; 5 - wane

The following elements are distinguished in lumber: layers, edges, ribs, ends. Face - the longitudinal wide side of the lumber, as well as any side of the lumber square section. The best face of lumber has the least amount of defects, best quality processing. The face of lumber facing the core is called the inner face, and the face facing the sapwood is called the outer face. Edge - the longitudinal narrow side of lumber. Edge - the line of intersection of two adjacent sides of lumber. End - the end transverse side of the lumber. Wane is not mandatory element lumber, this, so to speak, is an element of defective edged boards due to poor condition source material(logs or blanks).

Lumber is produced according to GOST 8486-86E:

1) from coniferous wood - pine, spruce, larch, cedar and fir;

2) from deciduous wood - beech, birch, alder, linden, aspen and poplar.

The following are used: boards with a thickness of 100 mm or less with a width to thickness ratio of 2 or less; beams with a thickness of more than 100 mm (four-edged and double-edged).

Length of lumber: softwood no more than 6.5 m, hardwood no more than 5 m. For special structures, lumber up to 9 m long, made to special order, can be used. The thickness and width of lumber are determined by the assortment (Tables 1, 2, 3).

Table 1. Standard output of edged lumber per 1 m 3 logs

Note:

1) When the grade of roundwood is increased to 1, the lumber yield standard increases by 3%.

2) When the grade of roundwood is reduced to grade 3, the lumber yield standard is reduced by 2%, to grade 4 - by 7%.

3) With a mixed supply of large and medium logs, the lumber yield standard is taken as the arithmetic mean between medium and large logs.

Table 2. Thickness and width of softwood lumber in mm

Table 3. Thickness and width of hardwood lumber in mm

The ends of lumber and rough blanks must be sawn at right angles to the longitudinal axis. Wane beams (with a partial absence of a cut in the edge) with a cross-section of 120 x 120 mm or more must have a cut width at the thin end of at least one third of the side of the beam.

The maximum permissible moisture content of lumber for load-bearing structures is 25%, for glued structures - 15%.

The use of lumber from hardwood is allowed for parts of rafters, internal stairs, internal linings walls and partitions, ceiling lining, eaves, pediments, internal architectural details, carpentry and clean floors.

The use of birch, linden and poplar wood for rafters is not allowed; linden, alder, aspen and poplar for treads wooden stairs; linden and poplar for clean floors.

Sawn timber yield rates from roundwood

Tags and key phrases

Not edged boards……………………………………………. 13 Business croaker………………………………………………….. 16 Sawdust and cuttings………………………………………………………. 13 Shrinkage………………………………………………………………. 8 When conducting practical calculations these figures should be refined based on studies of local conditions. Wood debarking waste. The amount of bark found on wood depends mainly on the species, as well as on the age of the trees, their growing conditions, trunk diameter, etc. The total amount of bark obtained by debarking wood at enterprises, taking into account the loss of bark during the logging process, varies ranging from 10 to 14.5% of the volume of marketable wood. When transporting wood by raft, part of the bark falls off and the actual yield of bark is on average 8...

Current norms for lumber yield when sawing

For example, with rot in the core, then the log is sorted and sawed into lumber, instead of being turned into timber.

Or vice versa, if the sapwood is rotten, but a beam emerges from the central part, and the log is a timber log, we sort it for sawing into timber.

You need to think similarly in terms of blueness and curvature.
Approximate yield by variety The situation by variety is quite interesting.

Attention

It turns out the percentage of output premium grades depends on the following factors:

• The coefficient of production of lumber from round timber.

Guidelines for determining the volume of secondary wood resources

Table 1 - yield of boards when sawing round timber Diameter, cm Yield of the highest grades, % 12 - 16 yield of the first grade 40% 18 - 22 on average 50% 24 - 26 about 50% 28 - 40 timber timber, in the production of timber you can get indicators about 70% 42 - 60 about 60 - 70% How does the percentage of lumber production depend on sawing technology? In addition to diameter, grade, defects (curvature) and length, the percentage of board output depends on the technology of sawing wood and the type of equipment.

Stages of sawing round timber

Info

He only cuts graded wood;

• Circular saw equipment cuts according to individual cuttings - this is a big plus for the resulting materials, both in quality and quantity.
Video on the topic And now I’ll answer why high yield is not always good, but everything is simple at very high rates, the amount of boards with wane increases.

Important

The result is low-grade lumber and its total cost from a log at a certain point becomes lower than the cost of high-quality materials.

Amount of wood waste

During the sawmilling process, various pieces of waste are obtained, which in some cases are used for energy purposes.

Lump sawmill waste is formed from the peripheral part of the logs and, in the absence of preliminary debarking of the logs, contains such an amount of bark that it is impossible to use it for pulping and the production of wood-based panels.

Volumes of formation of various types wood waste as a percentage of the volume of sawn raw materials are given in table. 14. Name of logging waste Including 13. Amount of waste generated during logging production Amount of waste per 1000 m1 of annual warehouse turnover, m3 Amount of waste from exported wood, % At the cutting site A.
Solid or lumpy from Hody: Branches, twigs, tops 14.00 140 65 75 Roots 11.00 110 .
110 - Stumps 3.00 30 30 - Points 1.75 17 - 17 Canopies 0.75 7 - 7 B.

Sawing round wood: cutting map, necessary tools

In what sequence should the round timber be cut? Please note! Coniferous wood species are considered the best option, due to the fact that they have a straight trunk and a relatively larger diameter.

In addition, such wood is not as susceptible to decay, which leads to less waste. When working with hardwood, 2 processing methods are used:

1. Using band sawmill at 375 or 363.
2. In ruins.

   This technology involves cutting out a half-beam, which is subsequently passed through a multi-saw device.

In this case, the first method allows you to get approximately 40-50% of the output.

But the collapse technique differs in a slightly larger volume - up to 70%.
The disadvantage of this technology is that its costs are relatively high.

Methods of cutting wood Sector - first the log is sawn into 4–8 sectors, and then each of them into radial or tangential materials.

Sometimes several unedged boards are cut in the center. Break-up-segment - with this type of cutting, two or more unedged boards are cut in the center of the trunk, and edged one-sided boards are sawed from segments on the sides. Beam-segment - similar to split-segment, only in the middle of the log a two-edged beam is cut, which is then sawn into edged boards. The yield of lumber is high. Circular - after sawing off one or more unedged boards, the log is rotated 900 and the next boards are sawed off. This method is used when a large log is affected by heart rot in the center. With its help, healthy wood is separated from low-quality wood.

How much waste is generated when sawing wood?

It's easier to do more difficult jobs with a chainsaw than to buy expensive equipment.

All you need for it is a special attachment, a barrel fastener and cutting guides.

Machines for removing bark. They are quite expensive, but with regular use in an enterprise where large volumes of work are performed, they quickly pay for themselves.

They are not required to be used, but are desirable because they can provide a number of economic advantages and conveniences in the production process.

The fact is that after some golden mean, the more planks we get per cubic meter, the higher the amount of low-grade wood with wane;

• The larger the diameter, the higher the likelihood of getting more high-quality boards;
• The presence of wood defects, such as curvature, rot, blueness and others; the fewer there are, the higher the percentage of obtaining a high-quality board;
• The shorter the finished product, the higher the percentage of high-quality boards.

Now let’s estimate, approximately based on the diameter, the percentage of first-class lumber obtained from the total volume of boards produced.

To do this, I made everything in the form of a small table.
Hello dear readers and subscribers of the blog, Andrey Noak is in touch with you! Today I will tell you about the yield of lumber when sawing round wood.

• 1. Introduction
• 2 Percent from round timber
• 3 Why does the useful percentage depend on the diameter of the wood being cut?
• 4 Ways to increase your ratio
• 5 Approximate yield by variety
• 6 How does the percentage of lumber production depend on sawing technology?
• 7 Videos on the topic

Introduction This parameter is one of the most important indicators in sawmilling.

The efficiency of sawing wood depends on this indicator.

Many beginners mistakenly believe that the higher this ratio, the better.

In fact, this is not always the case; most specialists know about this, but remain silent. I repeat once again - a high percentage of lumber yield per cubic meter of forest is not always good.