Lesnoy Zhurnal (Russian Forestry Journal)

Lesnoy Zhurnal (Russian Forestry Journal)

Basic info

  • Publisher: Northern (Arctic) Federal University named after M.V.Lomonosov
  • Country of publisher: russian federation
  • Platform/Host/Aggregator: Open journal system ojs
  • Date added to EuroPub: 2019/Sep/27

Subject and more

  • LCC Subject Category: Forestry, Technology
  • Publisher's keywords: Forestry, Technology, Machinery of logging, timber processing and chemical treatment of the wood biomass
  • Language of fulltext: english, russian
  • Time from submission to publication: weeks

Publication charges

  • Article Processing Charges (APCs): No
  • Submission charges: No
  • Waiver policy for charges? No

Open access & licensing

  • Type of License: CC BY
  • License terms
  • Open Access Statement: No
  • Year open access content began: 2001
  • Does the author retain unrestricted copyright? False
  • Does the author retain publishing rights? False

Best practice polices

  • Permanent article identifier: DOI
  • Content digitally archived in: eLIBRARY.RU
  • Deposit policy registered in:

This journal has '121' articles

Productivity of Forest Plantation Crops

Productivity of Forest Plantation Crops

Authors: V.A. Savchenkova, S.B. Vasilyev, V.F. Nikitin, P.A. Aksenov
Year: 2021, Volume: 10, Number: 1
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Abstract

Reduction of time for commercial wood cultivation and increasing the productivity of plantations is an urgent direction of scientific research considering supply of forest resources in the country and the growing need for timber. One of the ways of intensive forest reproduction is the creation of forest plantation crops. Plantation of forest crops involves the cultivation of technically valuable tree species in a shorter period of time. Our country has experience in the creation of forest plantation crops, but due to the reorganization in the forest industry, many areas were left without proper care. However, for 34 years research scientists at the Mytischi Branch of the Bauman Moscow State Technical University (formerly Moscow State Forest University) have been systematically monitoring the growth and development of spruce forest crops created in 1984 with intermediate agricultural use between the rows. The method of creating test crops is aimed at providing the most favorable conditions for growth and development of the main tree species in the first years after planting, the use of the natural growth of plantations during the entire period of crops cultivation, cost optimization for frequent silvicultural care, obtaining stands with high economic and aesthetic properties, prevention of wood defects. The article presents the technology of creating spruce crops, which is a distinctive feature of this method. We analyzed changes in the diameters and heights of trees grown by creating forest crops in the traditional way and with the use of intermediate agricultural use between the rows. The reliability of differences in the average values of independent samples was assessed, confirming the advantage of the spruce test crops. Their species composition is 100 % spruce, the absolute taper of which is 2.13 times less than those created by the traditional method. A higher probability of obtaining trunks with a volume of more than 0.02 m3 by creating test crops has been established. The results of statistical processing of experimental data indicate the prospects of the method of planting spruce forest crops with intermediate agricultural use between the rows, which contributes to the formation of high-quality stands.

Keywords: plantation of forest crops, intermediate agricultural use, forest crops, productivity
Dynamics of Carbon Stocks in the Formation of Forests on Post-Agrogenic Lands

Dynamics of Carbon Stocks in the Formation of Forests on Post-Agrogenic Lands

Authors: E.N. Nakvasina, Yu.N. Shumilova
Year: 2021, Volume: 13, Number: 1
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Abstract

Carbon stocks were calculated in different components of bigeocenosis (soil, living ground cover, forest floor, undergrowth, underbrush and forest stand) using the example of a selected chronosequence of fallows (4 sample areas of different age, yrs: 16, 25, 63 and 130) in the Kargopol district of the Arkhangelsk region (middle taiga subzone, residual carbonate soils). The structure of carbon stocks of the forming plantations and its changes with the fallow age is estimated. It was found that a natural increase in carbon stocks and its redistribution between the soil and the forming phytocenosis occurs in the process of succession during the afforestation of arable lands. In plantations growing on young fallows, more than 86 % of the carbon stock is represented by carbon from the arable soil horizon. During the colonization of the fallow by forest vegetation the share of this pool decreases and already in the middle-aged 63-year-old forest it is 22 %, and in the mature 130-year-old forest it is only 7.6 %. In the structure of the total carbon stock in the middleaged plantation, the share of the stand reaches 69 %, and in the mature 130-year-old stand it is already 90 %. In plantations on young fallows, the structure of the main components of biogeocenosis (soil carbon, ground cover carbon and tree layer carbon) is characterized by a ratio of 9:1:0, whereas in plantations on old fallows of 63 and 130 years it is 2:0:8 and 1:0:9, respectively. The undergrowth and underbrush of the studied chronosequence are characterized by the small shares of carbon, which do not have a significant value in the structure of the ecosystem carbon pool. Forest floor in forming forest stands contributes significantly to the carbon structure of the biogeocenosis, although the total biogeocenosis carbon pool is 3–4 % and does not contribute to an increase in soil carbon stocks. In the system “soil – forest floor – living ground cover” the share of soil carbon decreases from 91 to 76–77 % with the increase in the age of plantation, while the share of formed forest floor in the middle-aged and mature forest is 16 and 20 %, respectively. In plantations on young fallows the ratio of these components of biogeocenosis is 9:0:1, whereas on old fallows it is 8:2:0. Leaving arable land on residual carbonate soils for self-overgrowth with forest vegetation and formation of forest plantations on them in the middle taiga subzone will lead to a gradual decrease in the carbon pool in the soil, but will contribute to the sequencing of carbon in the phytomass of perennial woody vegetation and in forest floor. These two components of biogeocenosis will serve as a sequenced carbon depot, supporting the biological cycle.

Keywords: fallows, post-agrogenic forests, chronosequence, carbon stocks, biogeocenosis components, soil, stand, forest floor
Variability of Silvicultural Characteristics of Forest Shelterbelts in Krasnodar Krai

Variability of Silvicultural Characteristics of Forest Shelterbelts in Krasnodar Krai

Authors: N.V. Primakov
Year: 2021, Volume: 8, Number: 1
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Abstract

Modern shelterbelts of Krasnodar Krai do not fully protect arable land and often have different sanitary state. Under these conditions, the preservation of forest shelterbelts and their protective functions in the system of agroforestry and other complex continues to be relevant. The research was carried out in the main and auxiliary forest shelterbelts within the boundaries of the Ust-Labinsk district of Krasnodar Krai. The purpose of the research was to determine the ecological state of the forest shelterbelts by identifying their integrity and implementation of forestry and land reclamation assessment. In order to obtain more complete information on their state, a remote assessment of the tree canopy integrity of the shelterbelts was carried out. It follows from the remote assessment analysis that about 42.5 % of the area surveyed in the key plots of plantations has an average degree of integrity of tree canopy, high – 22.3 %, low and very low – 35.2 %. Lower indicators of the tree canopy integrity are observed in the auxiliary forest shelterbelts. The percentage participation of each group of forest shelterbelts allowed us to rank the ranges of integrity corresponding to a certain forestry and land reclamation assessment (units). The range of the tree canopy integrity from 0 to 25 % corresponds to grade 1, from 25 to 50 % – 2, from 50 to 70 % – 3, from 70 to 100 % – 4. Based on this, the shelterbelts were devided into 4 groups: norm, risk, crisis and disaster. The results of determining the ecological state of the forest shelterbelts by ground and remote methods in the Ust-Labinsk district of Krasnodar Krai showed that a significant part of the surveyed plantations has a dense structure and requires silvicultural care. The group of the forest shelterbelts “disaster” needs reconstruction. This will significantly improve the environmental condition and reclamation efficiency, as well as increase the service life of the systems of forest sheltebelts.

Keywords: forest shelterbelts, forestry and land reclamation assessment, sanitary assessment, degree of integrity, shelterbelt design, remote assessment, ecological state
Radial Growth of Scots Pine (Pinus sylvestris L.) under Inhibition

Radial Growth of Scots Pine (Pinus sylvestris L.) under Inhibition

Authors: V.P. Ivanov, S.I. Marchenko, D.I. Nartov, L.P. Balukhta
Year: 2021, Volume: 12, Number: 1
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Abstract

Predicting tree growth processes is important due to the exceptional ecosystem role of forests, which carry out global climate regulation by sequestrating carbon, conserving drinking water, and providing habitat for living organisms. Trees are known to respond to any fluctuations in the environment. The research purpose is to identify weather and climatic factors that significantly affect the inhibition of growth of Scots pine (Pinus sylvestris L.) in conditions of constant moisture deficit. The studies were carried out in the eastern part of the Bryansk region within the territory the Bryansk administrative district, in the educational and experimental forestry of the Bryansk State Engineering and Technological University and the Styazhnovskoye forest district. Methods of dendrochronology were used to assess the response of 93 pine trees to fluctuations in the external environment by changing the width of annual rings (available anatomical feature of a tree) using indices of radial growth. An original approach was proposed to analyze the reasons for a sharp decline in the annual radial growth under the influence of temperature and precipitation. The years with abnormally low increments (1963, 1972, 1985, 2002 and 2010) were identified against the background of the weather-climatic situation for 5 years before and after the fall in growth. Similar dynamics of absolute values of radial increments and their indices was established, which is caused by fluctuations of natural factors, manifestation of hereditary traits, etc. Significant differences were revealed between the growth rates at average multiyear values of January, May and August air temperatures with growth rates in the years of abnormally low radial growth, which are observed in pine against the background of colder January and warmer May and August of the current year, as well as under the condition of warmer January of the previous year. At the same time, no significant role of precipitation was detected. The obtained data, expanding the idea of the features of growth processes and formation of annual increments in diameter of Scots pine in the conditions of changing climate at the turn of the 20th–21st centuries, allowed us to suggest a possible manifestation of physiological features of the species, the homeostasis optimum zone of which is located in the conditions of colder boreal climate. This information expands our understanding of the features of growth processes and formation of annual increments in diameter of Scots pine in changing climatic conditions.

Keywords: Scots pine, radial growth, growth inhibition, dendrochronology, weather and climatic anomalies
Calorific Value of Pine Wood in Crops of the Northern Taiga Forest Area

Calorific Value of Pine Wood in Crops of the Northern Taiga Forest Area

Authors: O.N. Tyukavina, D.N. Klevtsov, D.M. Adaj
Year: 2021, Volume: 9, Number: 1
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Abstract

Calorific value of plants is an important characteristic for evaluation of material cycles and energy conversion in forest ecosystems, as well as a qualitative characteristic of plant raw materials as fuel. Wood biofuel is increasingly used in the production of thermal energy, in this regard, it is important to study the calorific value of wood, as well as the conditions for growing high-quality raw materials. The research purpose is to identify the dependence of the calorific value of pine wood in crops on its macroscopic structure, the assimilation apparatus characteristics, density and height of the stand. Small, medium, and large not damaged model trees without pathologies were selected on temporary sample plots. Cores from which were taken with an increment borer at a height of 1.3 m to measure radial growth on the semi-automatic complex Lintab-6 with an accuracy of ±0.01 mm. The calorific value of pine wood was determined in an absolutely dry state using an automated bomb calorimeter ABK-1V. To study the influence of the assimilating apparatus on the wood calorific value, needles of all ages were selected from the middle branch of the model tree crown. Cross sections were prepared from the middle part of a needle using a sledge microtome MS-2. Histological elements of a needle were measured by the Axio Scope.A1 microscope using the IMAGE-PRO INSIGHT 8.0 software. The average heat capacity of pine wood in heath-lichen pine forests is (20 731±133) J/g; in cowberry pine forests – (20 618±141) J/g; in bilberry pine forests – (20 513±104) J/g at a stand density from 1160 to 3806 pcs/ha. The highest pine wood heat capacity is found in heath-lichen pine forests with the density of stand 5021 pcs/ha. The increased pine wood heat capacity in pine forests with high stand density is due to a reduction in the number of needles on the branch (r = –0.75) and an increase in the diameter of resin channels (r = – 0.88). The influence of the average stand height and the annual layer structure on the calorific value of pine wood was found.

Keywords: calorific value, wood, pine, forest type, radial growth, needles
Stem Volume and Quality of Hybrid and Common Aspen in the Clonal Archive

Stem Volume and Quality of Hybrid and Common Aspen in the Clonal Archive

Authors: A.L. Fedorkov
Year: 2021, Volume: 6, Number: 1
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Abstract

Hybrid aspen as a fast growing tree species with short rotation is of interest for the creation of plantation forest crops in intensive forest management. Hybrid aspen wood is used to produce paper, lumber, and plywood, as well as biofuel. The research purpose is to compare the volume and quality of the stem of hybrid and common aspen, and to assess interclonal variability by these features in cold climate areas. The research results of 42 hybrid and 10 common aspen clones in the clonal archive of the Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences are presented. The archive was laid out in 2009 by 1-year-old rooted seedlings with a closed root system with the placement of plants 3×3 m. Donor plants were obtained at the Haapastensyrjä Tree Breeding Station of the Natural Resources Institute Finland. Scales have been developed for assessing plant health and stem straightness. Herewith, the height of trees, the presence of sores, scars and frost clefts on their stems were recorded. The share of tree-like and shrub-like plants was 70 and 5 %, respectively, with an average survival of 75 % at the 10-year biological age. Hybrid aspen was statistically significant in terms of superiority to standard aspen in diameter by 65 %, height by 49 %, and stem volume by more than 3 times. The share of slightly crooked stems was about 7 %, and the share of stems with bark cracks was about 3 %. Good survival, stem quality, and rapid growth of hybrid aspen made it possible to conclude that it is a promising species for plantation reforestation in the taiga zone.

Keywords: Populus tremula L., Populus tremuloides Michx., clones, stem growth, survival
Zoning of Catchments of Small Rivers in the South of the Volga Upland by the Water Protection Role of Forests

Zoning of Catchments of Small Rivers in the South of the Volga Upland by the Water Protection Role of Forests

Authors: O.Yu. Kosheleva
Year: 2021, Volume: 12, Number: 1
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Abstract

The article presents the results of the spatial distribution analysis of protective forest plantations within the catchment basins of in the south of the Volga Upland (within the Volgograd region). The data obtained are important for planning agroforestry and land reclamation. The interpretation of 133 reservoirs using satellite images and large-scale (Scale – 1:100 000) isolinear mapping of forest cover in the key areas allowed us to find that for the majority of catchments the low forest cover of the central part of the basin, caused by agricultural land use, is typical. The main environment protection function is performed by large forests of natural (growing in floodplains, uplands and steppe ravines) and artificial origin (forest shelterbelts), localized near the source (in watersheds) and the mouths of small rivers. Depending on the type of plantations and their presence or absence near the source or mouth of the river 6 types of forest cover of catchments in the south of the Volga Upland have been identified: I – river source and mouth have maxima (relative to the rest of the catchment basin) of natural forest cover; II – the source has a maximum of artificial forest cover, the mouth has a maximum of natural forest cover; III – there are no plantations at the source, there is a maximum of natural forest cover at the mouth; IV – there is a maximum of natural forest cover at the source, there are no plantations at the mouth; V – there is a maximum of artificial forest cover at the source, there are no plantations at the mouth; VI – there are no plantations at the source and mouth. It is found that the largest area within the south of the Volga upland is occupied by catchments of the III type (38.3 %), the relief of which is characterized by the predominance of gentle slopes, which have been exposed to the greatest extent to plowing and destruction of natural forest vegetation. Together with catchments of the IV–VI types, having no afforestation in the lower stream, about 59.2 % of plantations of the south of the Volga Upland are not protected from the processes of water erosion and deflation.

Keywords: protective forests, Volga Upland, catchment, forest cover, space image interpretation, isolinear mapping, zon
Influence of Chronic Ionizing Radiation on the Variability of Mitotic Activity of Pinus sylvestris L. Tissues

Influence of Chronic Ionizing Radiation on the Variability of Mitotic Activity of Pinus sylvestris L. Tissues

Authors: A.V. Skok, V.N. Sorokopudov, I.N. Glazun
Year: 2021, Volume: 7, Number: 1
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Abstract

The development of nuclear power engineering will increase in the future, due to the continued likelihood of radionuclides entering the environment. The relevance of studying the genetic material of conifers as a reliable bioindicator was revealed. It is known that under the influence of ionizing radiation there is an accumulation of genetic abnormalities in pine (Pinus sylvestris L.) progeny. The stages of gametogenesis, zygotes and young seedlings of plant organisms are most sensitive to ionizing radiation. It is important to determine the variability of the mitotic index (MI) of tissues of Scots pine (Pinus sylvestris L.) progeny in areas with different levels of ionizing radiation, including in the exclusion zone. The exposure dose rate was measured at the soil level and 1 m from the ground surface. Germination of seeds was carried out in a thermostat on wet filter paper. Roots of seedlings 0.5–1 cm long were fixed in a mixture of 96 % ethanol and glacial acetic acid. Root staining was carried out in a solution of acetocarmine. Tissue softening was carried out with a strong chloral hydrate solution. The total number of dividing cells, as well as pathological mitoses (PM) were counted on squash preparations using a microscope. The mitotic index and the duration of the phases of mitosis were determined. An increase in the level of radioactive contamination increases the cell division rate in prophase, anaphase, and telophase, but decreases the duration of metaphase, and also changes the relative duration of mitosis phases. With an increase in the exposure dose rate, the number of pathological mitoses naturally increases. The spectrum of mitosis disorders is represented by various abnormalities of the chromosome apparatus in anaphase: exit and lagging of chromosomes, bridges. Herewith, the number of anaphases with bridges increases significantly with simultaneous exit and lagging of chromosomes.

Keywords: Pinus sylvestris L., exposure dose rate, mitosis phases, anaphase abnormalities, bridges, chromosome lagging, chromosome exit
Typification of Forest Areas by Natural-Production Conditions Based on Cluster Analysis

Typification of Forest Areas by Natural-Production Conditions Based on Cluster Analysis

Authors: I.R. Shegelman, P.V. Budnik
Year: 2021, Volume: 17, Number: 1
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Abstract

The effectiveness of harvesting machines, their reliability, and the level of negative environmental impact depends on the degree of adaptation of the equipment to natural-production conditions (NPC). To choose the equipment it is necessary to allocate groups of areas with close NPC. The purpose of the study is to form methodological tools for forest industry typification of forest areas by NPC. It is proposed to carry out the typification of forest areas based on cluster analysis. For this purpose, a methodology has been developed, including: setting the goal of typing areas by NPC; data collection on NPC; conducting cluster analysis; decision making on typification of areas by NPC. The task of cluster analysis is to divide, on the basis of a certain set of data, the set of forest areas into groups with similar NPCs. It is proposed to use Euclidean distances as a measure of belonging to one of the groups, and to determine the data set by indicators describing the NPC. The proposed methodology has been tested on the example of the European North of Russia (ENR). The study showed that three zones can be distinguished in ENR: zone A, including the Murmansk region; zone B, including the Republic of Karelia, the Republic of Komi and the Arkhangelsk region; zone C, including the Vologda region. Additionally, two subzones are distinguished in zone B: the West Karelian Upland and the territories belonging to the Northern, Subpolar and Polar Urals. The proposed methodology allows to increase the degree of formalization and convenience of the typification process of forest areas by NPC, to take into account a wide range of various aspects of natural-production conditions, their probabilistic nature, as well as to flexibly carry out the typification of areas for specific purposes. The research results may be applicable in solving problems of searching for effective technologies and rational parameters of logging machine systems.

Keywords: typification of forest areas, natural-production conditions, logging operations, cluster analysis
Improving the Efficiency of Multifunctional Machines for Intensive Forestry

Improving the Efficiency of Multifunctional Machines for Intensive Forestry

Authors: E.F. Gerts, A.V. Mekhrentsev, V.V. Pobedinsky, N.N. Terinov, A.F. Urazova
Year: 2021, Volume: 11, Number: 1
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Abstract

The method of intensification of forestry by means of integrated mechanization of forestry and logging operations is considered. It is proposed to use manipulator-type machines, such as harvesters, forwarders and excavators, as a technical basis. Improving the efficiency of manipulator-type machines can be achieved through using a set of optional interchangeable equipment. This will allow to create crops by planting seedlings with open and closed root systems, to carry out soil cultivation, seed sowing, thinning of young plants and to carry out pest control, mulching of skidding tracks after major work in the logging site, as well as earthworks during the construction of forest roads. The use of optional interchangeable equipment transforms a manipulator-type machine into a multifunctional machine. It has been shown that the purchase of optional equipment for forestry and logging is a cost-effective investment even for a small amount of works. Intensive forestry is primarily based on the measures of mature and overmature stands cutting, forest tending, and reforestation. Several technological schemes with the use of the multifunctional machine for felling both in the harvester and feller buncher modes are offered. In the latter option, tree length bucking and branch pruning ensure the concentration of all logging residues at the upper depot and create favorable conditions for their processing into raw material for biofuel production and reduce woodwaste in cutting areas. An option of using small size equipment for hauling trees into the area of operation of a multifunctional machine with an installed harvester head is offered when performing selective felling using wide-strip technology of harvesting. Preliminary preparation of the cutting area with small sized equipment (harvesting of small-sized, dead and fallen trees) is proposed. This will significantly reduce the damage to plantation components and provide a greater degree of preservation of the natural environment during the main work of the multifunctional machine. Its use in the most favorable terms due to the work execution on a quarter-block scheme, reducing the number of downtime due to naturalproduction conditions and the number of relocations and, accordingly, increasing the number of machine hours, will minimize total costs of the range of forestry and harvesting works.

Keywords: complex mechanization, multifunctional machines, interchangeable equipment, quarter-block organization of works
Optimization of Log Sorting by Diameter

Optimization of Log Sorting by Diameter

Authors: V.V. Ogurtsov, E.V. Kargina, I.S. Matveeva
Year: 2021, Volume: 8, Number: 1
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Abstract

This work is the final in the series of studies related to the issue of sorting logs by thickness while forming the sawing batches with optimal selection of sawlogs by diameter groups. In previous works, mathematical models linking the characteristics of logs and their cutting processes with the timber volume output and the sawmill profitability were obtained. Algorithms and programs for simulation studies of the sawn timber production process with reproduction of random variability of sizes and shapes of sawn logs, as well as their random displacement relative to the center of the sawing pattern were developed. Profitability of sawmill production was chosen as the criterion of optimality, the volume output of timber was used as a competing indicator. Fractional sorting of logs by thickness is used as a controllable optimizable variable, while ellipticity, curvature, and timber displacement from the center of the sawing pattern are treated as random interfering factors. Considering the log as a set of short sections threaded on a curved axis, we imitated its sawing process with random characteristics of shape and sizes. As a result, the change patterns of sawing production efficiency were determined while varying thickness, curvature, ellipticity and displacement of logs from the center of the sawing pattern. It was found that when sawing logs with an optimal sawing pattern, the simultaneous influence of random factors of log shape and accuracy of its location weakens the dependence of the timber volume output on the fractional sorting of logs according to the law close to the geometric summation of individual influences. Factors with large influence practically absorb factors with a smaller influence. The log curvature dominates among them. For suboptimal sawing patterns with the simultaneous influence of the three considered factors, the timber volume output is practically independent of the fractional sorting of logs by thickness. When sawing logs with shape defects by suboptimal sawing patterns on equipment with an imperfect basing system, sorting logs by thickness as a way to increase the volume output of sawn timber does not make sense. Random variation of log shape and accuracy of its centering, as well as the deviation of the parameters of sawing patterns from the optimal, causes a decrease in the optimal fractionality of selection of logs by thickness from 20 to 30 mm. Moreover, the greater the number of characteristics of log shape and its basing deviates from the ideal values and the greater these deviations, the more active the optimum fractional sorting of logs by thickness shifts to 3 or more even diameters. When preparing sawn material for mass sawing using modern technologies and equipment with rigid sawing patterns, it is advisable to sort logs by thickness through 2 even diameters. At random simultaneous variation of ellipticity of cross-sections of logs with an average value of 6 mm, their curvature with an average value of 0.25 % and displacement relative to the center of sawing pattern with an average value of 10 mm the optimum is sorting of sawn raw material through 3 even diameters.

Keywords: log, ellipticity, curvature, basing, sorting, fractionality, sawing, profitability
Complex Efficiency of Using Wood Pellets in Power Plants

Complex Efficiency of Using Wood Pellets in Power Plants

Authors: V.K. Lyubov, A.M. Vladimirov
Year: 2021, Volume: 13, Number: 1
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Abstract

In advanced countries, the dramatic impact of greenhouse gases on the global climate is reduced by replacing fossil fuels with biofuels. This method is being actively encouraged. However, by-products of logging, processing and conversion of wood are classified as difficult to burn fuels due to their high moisture content, low energy density and extremely heterogeneous granulometric composition. A promising direction to increase the energy density and transportability of the timber industry by-products is their granulation. Wood pellet fuel burning in heat-generating plants results in significant increase in their energy and environmental performance. The purpose of the paper is an experimental and calculation study of the energy and environmental performance of 4 MW hot water boilers produced by Polytechnik Luft- und Feuerungstechnik GmbH in the process of burning pine and spruce wood pellets obtained from by-products woodworking. When performing studies, the components of the boiler’s heat balance, gas release, and particulate emissions were determined. Numerical modeling of thermochemical and aerodynamic processes taking place in the boiler combustion chamber was carried out by using the Ansys Fluent three-dimensional simulation software. Together with industrial-operational tests it showed the possibility to reduce the total share of flue gas recirculation into combustion chambers of boiler units to values not exceeding 0.45, in providing an acceptable temperature of combustion products at the combustion chamber outlet and maintaining minimum emissions of carbon and nitrogen monoxides. At the same time, the share of gases fed by recirculation smoke exhausters to the over-bed area of the burner should have higher values than under the reciprocating grates of boilers. Guidelines for comprehensive improvement of wood pellet combustion efficiency in combustion chamber of 4 MW hot water boilers have been developed and implemented. The priorities are: using the air passed through the cooling channels of the setting as secondary air; reducing the rarefaction in the combustion chambers to 30–70 Pa; optimizing the ratio of primary and secondary air, herewith, the share of primary air in the total flow should be 0.26–0.35. Implementation of the developed guidelines allowed to increase the boiler gross efficiency by 0.5–1.8 %, to reduce the aerodynamic resistance of the gas path by 15–20 % and to ensure consistently low emissions of carbon and nitrogen monoxides and soot particles. When designing boiler units for burning wood pellet fuel it is advisable to place heating surfaces in the combustion chamber, included in the circulation circuit of the boiler. This will increase the efficiency and life cycle of the boiler unit.

Keywords: boiler, wood pellet fuel, harmful substances, numerical modeling, heat losses, efficiency
Studying the Rheological Properties of a Polylactide Melt Mixed with Wood Filler

Studying the Rheological Properties of a Polylactide Melt Mixed with Wood Filler

Authors: G.A. Sabirova, R.R. Safin, N.R. Galyavetdinov, A.R. Shaikhutdinova, R.Z. Khayrullin
Year: 2021, Volume: 6, Number: 1
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Abstract

Composite materials based on wood filler are promising materials that are actively conquering the market. This is due to the advantages of using these materials in various fields: weather resistance and environmental compatibility, easy machining and possibility of recycling. Furthermore, it is sustainable use of wastes of timber sawing and furniture and woodworking industries, as well as low-grade wood. Wood powder is also known to be one of the components of consumables used in additive 3D printing technologies. Over the last decade, the commercial use of 3D printers has increased rapidly due to the fact that it allows creating prototype objects of complex shape based on a computer model. Experimental studies were carried out to determine the tensile strength and rheological properties of a composite made of polylactide 4043D, untreated wood powder brand 140 and wood powder thermally modified at 200 and 240 °C. The composite is intended for creation of three-dimensional objects by extrusion using a 3D printer. It was found that with an increase in the amount of filler in the composite, the tensile strength decreases. Also, samples with thermally modified filler show an increase in tensile strength in comparison with samples with untreated filler. Prototypes of 3D threads with different composition were obtained, during the study of which the melt flow index was examined. It was found that with increasing temperature of wood filler treatment the melt flow index increases. With a lower content of wood powder in the melt composition, there is a 2-fold increase in the melt flow index. The knowing of the rheological properties of the resulting compositions will allow achieving maximum performance and reduction of energy and production costs.

Keywords: polylactide, biodegradable polymers, wood filler, thermal modification, 3D thread, rheological properties, melt flow index
Features of Solubilizing Effect of Amphiphilic Compounds during Pulp Deresination

Features of Solubilizing Effect of Amphiphilic Compounds during Pulp Deresination

Authors: R.A. Smit, E.Yu. Demiantseva, O.S. Andranovich, A.P. Filippov
Year: 2021, Volume: 9, Number: 1
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Abstract

The necessity to improve the existing technology of pulp deresination, in particular, to reduce the surfactants consumption and decrease the environmental load, led to a combination of existing methods of resin removal with the use of enzymatic treatment. The basis of the pulp deresination mechanism by amphiphilic compounds is the solubilization of resinous substances. Thus, the establishment of the patterns of this process and its control predetermines the success of implementation of the selected technology. The features of solubilization of triolein and rosin in the lipase-based systems of individual nonionic surfactants, the enzyme, as well as their synergistic mixtures with the determination of solubilization capacities of micelles and the possible mechanism of solubilizate incorporation into them were studied using spectrophotometry, pH measurement and dynamic light scattering. It was found that synthamide-5 has a low deresination capability in spite of the high solubilization capacity of its micelles and the production of aggregates with a hydrodynamic radius up to 98 nm after diffusion of rosin into them. It is likely that compact micellar structures with a developed surface, which are implemented in mixed systems of amphiphilic compounds, including the presence of synthamide-5 in them, are more preferable for successful deresination of pulp semi-finished products. The addition of lipase leads to an increased solubilization capacity of mixed aggregates and an increase in the intensity of solubilizate molecules incorporation. Thus, depending on the nature of the amphiphilic compound, there is a different mechanism for solubilizate incorporation into micelles. Determination of the size of associates in mixed systems showed the absence of enzyme denaturation, which predicts the successful application of such cooperative systems for deresination of fiber semi-finished products. It is found that the solubilizing capability of the studied systems on resin modeling objects correlates with their deresination capability with respect to different fiber semi-finished products.

Keywords: solubilization, pulp deresination, lipase, surfactants
Determination of the Mathematical Dependence of the Black Liquor Density on the Dry Matter Content (High Yield Softwood Pulp)

Determination of the Mathematical Dependence of the Black Liquor Density on the Dry Matter Content (High Yield Softwood Pulp)

Authors: Yu.V. Sevastyanova, Е.А. Toptunov, N.V. Shcherbak, P.V. Solntsev
Year: 2021, Volume: 8, Number: 1
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Abstract

A modern evaporator station is an energy-saving production of evaporated liquor with high dry matter content for ensuring the minimum SO2 emissions from the soda recovery boiler. Such stations are equipped with Falling Film devices and consist of 5–7 stages. The necessity to improve and create new black liquor concentrators is driven by the increased attention to environmental issues and the wish to produce liquor with a higher calorific value. The physical properties of black liquor depend on its composition and have a significant impact on the selection and design of evaporators. The main properties considered in the evaporation and combustion processes are density, viscosity, surface tension, heating value and boiling temperature. One of the most important characteristics of the liquor evaporation is its viscosity, since it determines the ability of the liquor to pump and affects the design features. Another equally important characteristic is density. With its help, the dry matter content and evaporation process in the main stages of the liquor regeneration are regulated. The study was carried out to determine the mathematical dependence of the black liquor density on the dry matter content for high yield softwood pulp. The study objectives were the following: analyze the effect of the dry matter temperature and concentration on the density of black liquor obtained from cooking high yield softwood pulp according to the technological flow of production; develop a mathematical model of dependence of the black liquor density of high yield sulphate softwood pulp on the concentration and temperature; conduct the TAPPI comparative testing of the results of mathematical and correlation dependences. A mathematical dependence of the black liquor density on the temperature and dry matter content required for immediate technological calculations of chemical regeneration departments in sulphate production of semi-finished products for cardboard was obtained. The following equation of mathematical dependence based on the conducted research, regression analysis, and mathematical processing of the results was obtained: ρ = 0.974 + 0.0071x – 0.0002t – 0.000007xt – 0.00000045t2 – 0.0000045x2 (where ρ – density, g/cm3; x – dry matter content, %; t – temperature, °C). It allows calculating with the highest accuracy the density of black liquor obtained from cooking high yield softwood sulphate pulp. Comparative testing of the results of the developed mathematical dependence and correlation dependence (published by TAPPI) of black liquor density on the dry matter content was carried out. A high level of comparability of the proposed mathematical equations was found.

Keywords: high yield sulphate pulp, chemical recovery, black liquor physical properties, dry matter content, black liquor density, evaporation, mathematical model

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