Cutting of Round Timber with Heart Rot to Structural Lumber

Softwood lumber is widely used for the manufacture of load-bearing structures. However, the quality of round timber for lumber manufacturing has been deteriorating recently. The average diameter of round timber entering sawmills is constantly decreasing, and heart rot is common in large-diameter round timber. This is due to the fact that more and more conifers in the forest are being affected by heart rot. The rot infestation is related to the deterioration of the ecological situation caused by environmental pollution. As a rule, the removal of rot occurs at the stage of round timber harvesting. Therefore, during harvesting, most of the wood with heart rot continues to remain in the forest. In addition to littering the area, it continues to infect sound wood. At the same time, together with the wood affected by rot, the sound sapwood, which has good strength characteristics, is also removed. A method for processing round timber with heart rot into elements of load-bearing structures is proposed. In particular, a technological scheme for manufacturing I-beams from such timber has been developed for low-rise house construction. Corner elements are produced as a result of cutting round timber and removing heart rot by milling. The corner elements are dried in clamped state using special devices. Then they are glued together to obtain beams with a cross-section in the form of an I-beam. A set of equipment for the processing round timber with heart rot was selected. The paper presents the results of calculating the costs for organizing the production. The effectiveness of the technological project is evaluated using the method of discounted cashflows by the following indicators: net present value, profitability index, and discounted payback period. The assessment results confirm the effectiveness of the production organization of load-bearing structures made of round timber affected by heart rot. The processing of wood that remains in the forest into elements of building structures not only increases the wood reserves for construction, but also creates conditions for improving the ecological situation in forest areas. For citation: Toropov А.S., Byzov V.Е., Toropova Е.V., Sergeevichev А.V., Sazanova E.V. Cutting of Round Timber with Heart Rot to Structural Lumber. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 160–172. DOI: 10.37482/0536-1036-2021-6-160-172

Solving the problem of optimizing the cutting of wood whips with curvature

Stem wood, obtained from the cuttings of care in low-forest areas is of low quality. Such wood has a number of vices, one of which is simple curvature, which has impact on the voluminous and commercial output of round timber. Reducing this influence can be achieved through high-quality bucking. Therefore, the purpose of the work presented is to increase the volume and commercial output of round timber harvested in low-forest areas. The developed technique using computers allows to solve the tasks of modeling the shape of wood whips and logs using multi-critical optimization and bucking whips having curvature. The use of the proposed technique allows for results adequate to the real production conditions, as evidenced by the methods of decision-making used. Scientific research and theoretical developments, taking into account the formed database, allowed to search for the optimal scheme of cutting when bucking round timber, performed according to the algorithm based on the busting of acceptable variants using modern theory of graphs and matrixes. As a result, the developed program will reduce the time for data formation, guarantee the accuracy of the results, the program easily adapts to natural and production conditions and will expand the possibilities for Computer-aided design.

Justification of the forces required for leveling ends of floating packaged rafting units

При реализации концепции, обеспечивающей экономическую доступность удаленных лесных ресурсов, предусматривается сплотка малогабаритных пакетов круглых лесоматериалов в двухъярусные единицы в пунктах выхода с мелководных участков рек на глубоководные. Указанная сплотка предполагается в специальных устройствах, где предусматривается, в частности, торцевание сплоточных единиц с целью повышения экономических показателей дальнейшей транспортировки и надежности сохранения их целостности. Для обоснования параметров устройства нужна информация о требуемых усилиях для торцевания плавающих пакетов и двухярусных единиц из них. Установлено, что для ее получения нужны дополнительные исследования. Очевидна целесообразность общей методологии для двухъярусных единиц и составляющих их пакетов, с которых и следует начать исследования. С целью получения зависимости для расчета усилия, необходимого для торцевания плавающих пакетов, использовали теоретический метод, базирующийся на эластиковой теории. При этом плавающий пакет рассматривали как гибкую оболочку, заполненную двумя видами сыпучей среды с разным объемным весом. Граница сред проходит по поверхности воды. Линия обвязки, то есть гибкой оболочки представляет собой комбинацию фрагментов двух эластик с разными характеристиками. Используя параметрические уравнения, описывающие форму эластик, и зависимости для определения давлений в сыпучих средах, получили искомую аналитическую зависимость и ее упрощенный вариант для практических расчетов. Результаты расчетов по предложенной формуле превышают результаты, вычисленные по формуле, полученной ранее по другому алгоритму действий без учета давления обвязок, на 70% при коэффициенте формы пакета 1,5, то есть при сильном давлении обвязок и примерно на 10% – при коэффициенте 2,5, то есть слабом их давлении. Это позволяет считать результаты исследования достоверными, применение использованной методики для соответствующего исследования двухъярусным единиц – целесообразным. Установили, что при фиксированной плотности лесоматериалов наиболее существенно влияют на усилие торцевания изменения отношения высоты пакета к среднему диаметру лесоматериалов, его коэффициента формы и объема. Влияние первых двух факторов в аналитической формуле учитывается множителем, величину которого в практических расчетах можно определить по предложенным графикам или аппроксимирующим зависимостям. When implementing the concept that ensures the economic accessibility of remote forest resources, it is envisaged to raft small-sized packages of round timber into bilevel units at the points of exit from shallow-water sections of rivers to deep-water ones. The specified raft is assumed in special devices, which provide the leveling ends of rafting units to increase the economic indicators of further transportation and the reliability of maintaining integrity. To substantiate the parameters of the device, information is needed on the required forces for leveling ends of floating packages and bilevel units of them. It was found that to obtain it requires additional research. The expediency of a common methodology for bilevel units and their constituent packages is obvious, from which research should be started. To obtain the dependence for calculating the force required for leveling ends of the floating packages, a theoretical method based on the elastic theory was used. In this case, the floating package was considered as a flexible shell filled with two types of granular media with different bulk density. The boundary of the media runs along the surface of the water. The strapping line, that is, the flexible casing, is a combination of fragments of two elastics with different characteristics. Using parametric equations describing the shape of elastic and dependences for determining pressures in bulk media, we obtained the required analytical dependence and its simplified version for practical calculations. The calculation results according to the proposed formula exceed the results calculated according to the formula obtained earlier using another algorithm of actions without considering the pressure of the straps by 70% with a package shape factor of 1.5, that is, with a strong pressure of the straps and by about 10% – with a coefficient of 2.5, that is, their weak pressure. This allows us to consider the results of the study reliable, the use of the methodology used for the corresponding study of bilevel units is expedient. It was found that at a fixed density of timber, the most significant effect on the force of leveling ends is changes in the ratio of the height of the package to the average diameter of timber, its shape factor and volume. The influence of the first two factors in the analytical formula is considered by a factor, the value of which in practical calculations can be determined from the proposed graphs or approximating dependences.

On the prospects for the ban and control of the export of timber

Based on the analysis of the legal framework, the official statistics of the Federal Customs Service of Russian Federation and world practice, the article discusses the issues of banning the export of round timber outside the Russia. The potential economic effect for individual regions and for the country as a whole as a result of such a ban is estimated, as well as the impact on the foreign trade activity of the Russian Federation. In addition, the potential risks associated with the ban on the export of round timber are assessed.

Acacia crassicarpa (northern wattle).

A. crassicarpa is one of the fastest-growing acacias for planting on degraded sites in the seasonally-dry tropics. It tolerates a range of soil types, particularly those of low fertility. It is a nitrogen-fixing tree that produces abundant natural root nodulation. It is fire resistant and competes favourably against weed species such as Imperata cylindrica. It has the potential to produce a dense hardwood that can be used in industrial pulp production, as sawn or round timber for construction or as fuelwood.

Applying Machine Strength Grading System to Round Timber Used in Hydraulic Engineering Works

Round timber is often used for hydraulic engineering works, but the strength grading of round logs is not as well developed as that of sawn timber. The advantages of using defined strength classes, as well as the proper selection of the raw material, could be applicable to hydraulic works as well. In this study, the methods and rules developed for sawn timber were applied to the mechanical selection of oak round logs, paying particular attention to the issue of the simplicity of grading operations and the moisture content of the timber. Both the acoustic velocity and dynamic modulus of elasticity of oak logs were measured with different instruments before performing destructive bending tests; machine settings were derived for both properties and dry and wet grading operations were simulated to compare efficiency. The use of the dynamic modulus of elasticity makes machine grading more efficient. On the other hand, the use of acoustic velocity alone is feasible and makes the procedure much faster, even if wet grading resulted in very conservative estimations. The yields obtained were similar for lower grades, but to achieve higher strength classes, the dynamic modulus was preferable. For very fast and less expensive measurements, velocity could be considered an appropriate method, as an improvement over the use of unselected material.

Restrictions and prohibitions in the field of timber export in Russia in modern conditions

The article analyzes the measures of state regulation of the export of unprocessed timber, aimed at reducing the volume of its export from the country and providing raw materials for Russian timber industry enterprises. The tools are given to support the restructuring of the logging business for deep processing of wood in the context of a ban on the export of unprocessed coniferous timber from Russia. A differentiated and gradual transitional period for the implementation of the ban on the export of industrial round timber is proposed, during which the modernized version of LesEGAIS can become an effective tool for controlling timber transactions.

Improving the efficiency of timber sawing process by increasing reliability of attachments for forestry equipment

The current state of the timber industry complex and the prospects for its further development indicate the need to revise the approach to organizing logging process as a resource-saving, economically and environmentally sound process. Rational nature management and careful use of available forest resources come to the fore. Today, logging machines are an integral part of logging, and technical condition of the equipment of these machines has a direct impact on their productivity, quality of round timber and amount of sawmill waste received. The paper presents a design solution that makes it possible to increase efficiency of forest machines in freezing temperatures, which increases their productivity and the quality of the resulting roundwood by reducing the generated logging waste.