Outbreaks of Ips typographus (L.) caused by catastrophic natural phenomena in Central Europe, Siberia and the Far East have been the subject of numerous scientific studies. Molecular methods were used to analyze the relationships and origin of Ips species. The review article shows in detail the biological characteristics of I. typographus, such as the effect of temperature on vital parameters and flight behavior. It was found that the spruce bark beetle disperses within 500 m. However, new attacks occur in the immediate vicinity of the old foci. The susceptibility and protection mechanisms of trees are critical to a successful bark beetle attack. The newly attacked trees react with preformed resin, reactions to wounds, and, ultimately, systemic changes in physiology. The risk assessment in the studies was carried out both at the tree level and at the forest level as a whole. The risk of an attack of I. typographus is associated with the growth of the forest in a particular area, age, the flow of nutrients and water to the tree. The dynamics of outbreaks, to a large extent, depend on the abundance of I. typographus, susceptibility of trees, weather conditions and phytosanitary measures. Bark beetle I. typographus is an integral component of any forest ecosystem. It colonizes weakened, weak or dead trees, and thus begins the decomposition of bark and wood. This pest is able to use short-lived resources and quickly multiply to extremely large numbers, for example, after winds. In such epidemic situations, I. typographus can pose a serious threat to spruce-rich forests, especially for stands planted outside their optimal range. The spatial development of I. typographus infections can be analyzed using GIS and multiple regression methods to investigate potential correlations between climatic, specific and phytosanitary factors and infection dynamics. Also, the article discusses various methods of forest control and emphasizes the need for more sophisticated risk assessment tools.

The implementation of tasks related to the development of the transportation network as a whole and logging roads as an integral part of it requires scientifically based theoretical studies of the patterns of formation of spatial curves when combining elements of the plan and the longitudinal profile, since the rational laying of the route for many years determines its most important transport and operational characteristics (speed, traffic safety, traffic capacity). Consideration of the visual perception of the road by the driver will improve the quality of design decisions, which will allow to avoid emergencies in the future after setting the route into service. On the other hand, a decrease in speed before seemingly sharp turns of the road affects the efficiency of logging road transport. Therefore, the view of the road ahead should strongly orient the driver, i.e. be visually clear and clearly changing, ensuring the constancy or smooth reduction of the traffic flow mode. At the same time, the need for a successful spatial solution of the road increases. In the designs of logging roads, straight lines, transition curves, described in recent years most often according to the clotoid, and circular curves are found as elements of the route plan. It is found that the road view in perspective correctly orients the driver of the car, i.e. it is visually clear, provided that the lines describing the edges of the roadway and the edges of the roadway in the perspective image are curved in the same direction as in the road plan. The purpose of the work is to determine a set of quantitative indicators (curvature, radius of the curve in the plan, maximum curvature, maximum rate of change of curvature) for optimization of the visual smoothness and clarity of the central projections of elementary spatial and plane curves. The performed studies allow us to fully characterize the visual smoothness and clarity of the central projections of elementary spatial and plane curves. The above algorithm makes it possible to compile a computer program to determine the mentioned indicators. The indicators determined by this algorithm allow us to evaluate both the visual smoothness and clarity of curves on logging roads.

The creation and cultivation of artificial plantations of conifers largely depends on the planting material quality. The paper is devoted to the study of the relationship between the main parameters of planting material of Scots pine (Pinus silvestris L.) with inventory indices of artificial plantations. Forest trials of Scots pine in the Arkhangelsk region, created in a haircap-moss forest site type, were investigated. Seedlings of Scots pine with standard size were divided into large, medium, small according to the diameter of the root cervix in order to set the experiment, which aimed to determine the relationship between the parameters of planting material and characteristics of the forming plantations. The research purpose determined the main task, mainly, to find out from which plants the “trees of the future” (fast-growing large specimens) are laid out. Plants grown from the large seedlings are characterized by the greatest height. This position, in relation to individuals formed from medium and small planting material, is maintained and gradually increases. From the initial phases of development, a kind of mobile equilibrium is established in the studied plantation. All the trees are growing at a very fast rate, but the initial (at the time of planting on the silvicultural area) size of the planting material corresponding to the pine plants that survived in different years on the plantations continues to remain constant. It was found that, the largest number of leaders (47 % of all survived seedlings) grew of the large seedlings by the end of the 2nd age class. Therefore, high-quality soil treatment together with the use of high-quality proportionally developed planting material significantly increases the inventory indices of plants in the stand, and allows getting the target assortments15–20 years earlier.

The main drivers of competition among the products made with the use of adhesive compositions are the toxicity of finished products, the consumption of raw materials and energy resources, the duration of the main technological operations. These drivers can be controlled by using adhesives with different fillings and/or modifications. Adhesives based on phenol-formaldehyde and melamine-urea-formaldehyde resins are used to produce plywood with increased water resistance. Apart from resins, adhesives usually contain hardeners, fillers, and modifiers that affect the properties of the finished product. Technical aerosol is one of the modifiers of synthetic resins with a wide range of action. Aerosil is characterized by three types of interaction: physical adsorption, chemical adsorption (formation of hydrogen bridges by silanol groups), and chemical reactions on the surface layer. The chemical composition of aerosil was analyzed. Technical aluminum fluoride (AlF3) is of particular interest. It can interact with alkali metal fluorides with the formation of complex compounds that improve polymer structuring. The acids that make up aerosil reduce the pH to 2.0–3.5, so they can be catalysts for the curing process of melamine-urea-formaldehyde resins. The effect of technical aerosil on the properties of adhesive systems based on phenol-formaldehyde and melamine-ureaformaldehyde resins has been studied. Viscosity, curing time, and wetting ability of adhesive compositions were determined. The obtained results indicate the possibility of using this modifier in the composition of phenol-formaldehyde and melamine-urea-formaldehyde resins up to 15 pts. wt. The nature of the aerosil action on adhesive compositions was determined using IR spectroscopy. Analysis of the results showed that aerosil promotes deep structure formation of the polymer by increasing the molecular weight of the molecules. These bonds make it possible to form a more structured polymer with bound formaldehyde. Studies of the effect of aerosil on the properties of finished products were carried out. At the same time, an increase in performance indicators was found: the strength of adhesion increases, the toxicity of plywood decreases. The results of experiments on the effect of technical aerosil, taking into account the reduction of bonding time can be applied in the development of technological processes for obtaining plywood of high water resistance. For citation: Sokolova E.G., Rusakov D.S., Varankina G.S., Chubinsky A.N. Effect of Technical Aerosil on the Properties of Adhesive Compositions. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 133–144. DOI: 10.37482/0536-1036-2021-3-133-144

Siberian larch (Larix sibirica L.) is the main commercial species in Russia. Currently, larch woody greens are underutilized. They are considered a waste product from logging. This is due to the lack of knowledge on the composition of compounds and the variability of the raw material source itself as a result of the fall of the needles. The research purpose is to study the composition of hydrocarbons and esters from Siberian larch needles in summer and autumn collection from the Tomsk region. The shredded needles were extracted with propan-2-ol; then, after distillation of the solvent, substances soluble in petroleum ether (PE, 40–70 °С) were isolated. The latter were divided into free acids (31.5 % for green needles and 28.0 % for yellow needles) and neutral substances (59.8 and 48.1 %, respectively). Then, eutral substances were chromatographed on silica gel: hydrocarbons (2.43 and 3.02 %, hereinafter from neutral substances of green and yellow needles, respectively), esters (31.30 and 33.80 %) and triglycerides (11.70 % and 6.44 %). The ester and triglyceride fractions were exposed to alkaline hydrolysis and the acidic components of esters (9.12 and 24.80 %) and triacylglycerols (17.43 and 26.15 %) were produced. Fractions of unsaponifiable compounds, in addition to alcohols, contained unsaponifiables with unchanged Rf values on thin-layer chromatography (TLC). Fractions of unsaponifiables were chromatographed on silica gel, and then the isolated fractions were additionally chromatographed on silica gel with silver nitrate. The isolated compounds were identified by nuclear magnetic resonance (NMR) spectroscopy. In the acidic component of esters, the main components are linoleic and linolenic acids. Hydrocarbons are represented by sesquiterpenes in both collections of needles. A new aromatic hydrocarbon for coniferous plants, geranyl-p-cymene, has been identified. For the first time, polyprenols were isolated from Siberian larch greens, the structure of which differs from spruce and pine polyprenols by chain length according to NMR spectroscopy and mass spectrometry data. They contain from 14 to 20 isoprene links in the chain of molecules with predominance of prenol-17. The yield of polyprenols was 12.8–14.9 % of neutral substances of yellow and green needles, respectively. Tetracyclic triterpene alcohols and sterols were isolated from green needles. Triterpene alcohols were not found in yellow needles. For citation: Mikson D.S., Roshchin V.I. Hydrocarbons and Ethers of Extractive Substances of Siberian Larch Needles. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 170–185. DOI: 10.37482/0536-1036-2021-3-170-185

The principles of increasing the use of modern multifunctional forest machines (harvesters and processors) for felling and delimbing in Russia and abroad are currently becoming more widespread and deserve increased attention from esearchers. The results of the studies performed made it possible to identify a wide range of constructive solutions of technological equipment interesting in the opinion of the authors of the publication and to develop a new technical solution. The idea of creating an additional shock load by the working body of multifunctional forest machines for delimbing during the processing of a tree trunk is one of the most effective options for the development of additional cutting force, allowing to facilitate the operation of the device. The proposed method involves delimbing the trunk by pulling rollers and is a combination of the operation of standard delimbing knives together with the gripping arms and a reciprocating delimbing knife that complements the design. The use of compressed air energy provides the reciprocating motion of the knife, creating a new principle of the cutting mechanism for this design. The article describes in detail the design of the device, its operation, as well as options for the interaction of individual technological elements. The implementation of the proposed idea will make it possible to introduce harvester and processor heads into the forestry sector, facilitating the operation of individual assemblies of forest machines with large average volume of the tree-length log. For citation: Rukomojnikov K.P., Kuptcova V.O. Design Improvement of the Mechanism of Delimbing by Multi-Operational Forest Machines. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 117–124. DOI: 10.37482/0536-1036-2021-3-117-124

Introduction of economically valuable and ornamental species has long been one of the main methods of increasing the biological diversity of dendroflora. The aim of the research is to develop the theory of stepwise introduction of dendroflora species in the northern direction. The methodological basis of research was the works of experts in the field of forest introduction, including northern specialists, such as F.B. Orlov, P.M. Malakhovets, V.N. Nilov, N.A. Demidova, O.S. Zalyvskaya, E.B. Karbasnikova, M.M. Andronova, etc. The article is mostly theoretical and describes the development of the introduction of tree and shrub species in the harsh conditions of the northeastern part of the Russian Plain. Analysis of the results of scientific and spontaneous introduction allowed us to formulate a working hypothesis on the possibility of implementing a stepwise introduction of dendroflora valuable species due to the special microclimate formed in cities with a higher level of temperature regime compared to the periphery. It is assumed that the thermal resource of heat islands should be enough for successful acclimatization of cultivars, promotion of their seed offspring to suburban conditions with subsequent naturalization. Statements covering the main aspects of stepwise introduction development have been formulated based on long-term research. These are the beginning of the first stage of acclimatization, factors influencing the duration of the introduction stage, priority material for processing the basic principles of stepwise introduction, limiting factors of the northern border of the introduction range, compliance of the conditions of heat islands with the conditions of the northern part of the previous introduction stage. Practical implementation of these statements will increase the efficiency of acclimatization tests of introduced plant species. A table of the acclimatization success and naturalization of dendroflora species, taking into account different stages of ontogenesis, was proposed in order to objectively evaluate the results of experiments. Synthesis of conclusions and recommendations contributes to targeted plant adaptation measures and the formation of reliable predictions of their naturalization. For citation: Babich N.А., Karbasnikova Е.B., Andronova М.М., Zalyvskaya О.S., Aleksandrova Yu.V., Gayevskiy N.P. Stepwise Introduction of Dendroflora Species to the Northeastern Part of the Russian Plain (Review). Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 73–85. DOI: 10.37482/0536-1036-2021-3-73-85

The article presents the results of the development of a technological mode for obtaining bisulfite hardwood pulp of high yield on a magnesium base for the production of various types of containerboard. The reliable and effective chemical and heat recovery technology implemented in the bisulfite method allows to use it in independent sulfite process. The effect of the duration of stay at the final temperature on the pulp yield and kappa number was studied when developing the technological mode of cooking. It was found that the increase in the duration of stay at the final temperature of 160 °C more than 40 min leads to violations of the selectivity of the cooking process. Increasing the duration of stay at the final temperature up to 70 min is accompanied by a decrease in pulp yield by 6 % at a constant value of the kappa number of the semi-finished product. Technological cooking mode: hydromodule 5, SO2 consumption 15.0 %, cooking solution pH 4.3–4.5, impregnation time at 120 °C – 35 min, cooking duration at 160 °C – 40 min. The mode allows to get a semi-finished product with a high yield of 60–65 % with a kappa number of 58–60 units without a hot grinding stage. An assessment of the mechanical strength characteristics of the laboratory samples of bisulfite pulp was carried out in accordance with the standards of the Russian Federation. The obtained values of bursting strength, resistance to flat compression, breaking strength, and breaking stress were comparable with the values of the industrial sample of hardwood neutral sulfite semi-chemical pulp with a semi-finished product yield of 75–78 %. It is shown that the presence of bark in the technological chips in the amount of 7.5 % is accompanied by a decrease in the yield of bisulfite hardwood pulp by 4.5 % and mechanical strength by 7.8 %. For citation: Koroleva T.A., Milovidova L.A., Dryakhlitsyn A.A. Production of High-Yield Hardwood Pulp by Bisulfite Cooking. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 161–169. DOI: 10.37482/0536-1036-2021-3-161-169

The increasing consumption of pulp for chemical processing, including production of sanitary tissue products and other medical products, food packaging, as well as fillers for food products leads to new requirements for the quality of raw materials. The task of improving the characteristics of pulp has become particularly acute in connection with the COVID-19 epidemic: the demand for disposable nonwoven materials in direct contact with the human skin has increased several times over. The elemental chlorine free (ECF) sulfate pulp bleaching process, which uses chlorine dioxide as a bleaching agent, dominates bleached pulp production worldwide. The chlorine-containing compounds formed as a result of bleaching pollute not only waste water, but also the product itself. In the near future, it is expected that paper products made with chlorine-based bleaches may be banned for the production of sanitary tissue products and food packaging. If the products of the pulp and paper industry do not meet international consumer requirements, the pulp market for these purposes may face undesirable results. The most promising direction of modernization the existing bleaching schemes, both in terms of the process consumption parameters and the quality of the produced pulp, is the use of oxygen-alkaline bleaching in the first stage. Determination of total and organically bound chlorine content in pulp materials in accordance with ISO 11480:2017 on the advanced plant has shown, that the introduction of bleaching schemes using oxygen-alkaline agents will ensure the recommended content of chlorine compounds while maintaining the necessary characteristics of pulp for the manufacture of medical and sanitary tissue products, food packaging. However, high quality of finished products that meet consumers’ requirements is possible only if the chlorine content is controlled at all stages of pulp production, since the quantitative indicators of this substance content remain close to the upper allowable limit. For citation: sofronova e.D., Lipin v.A., Dubovy v.K., Sustavova t.A. Minimizing the Chlorine Content in bleached sulfate pulp for sanitary tissue products and food packaging. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 186–195. DOI: 10.37482/0536-1036-2021-3-186-195

Uncontrolled development of unfavorable vegetation during artificial reforestation reduces survival and growth rates of planted trees, and in some cases causes their death. The use of reforestation equipment is often extremely difficult, therefore the most promising solutions are those involving creation of spruce plantations using seedlings with closed roots and manual planting tools without preliminary mechanical tillage. Long-term protection of plantations from undesirable vegetation is ensured by the use of modern herbicides registered for use in the forest sector in the Russian Federation. The article presents the results of 3-year field experiments on the use of herbicides and their mixtures to supress undesirable vegetation in the first years after planting European spruce (Picea abies (L.) Karst.) in the Leningrad region. High efficiency of herbicides for long-term suppression of shrubs, and herbaceous and woody plants was found. A mixture of herbicides Roundup, WS (360 g/L glyphosate acid), Anchor-85, WDG (750 g/kg sulfometuron-methyl potassium salt) and Arsenal, WC (250 g/L imazapyr) inhibited the development of herbaceous weeds for at least two growing seasons. The processes of undesirable vegetation development after spraying plantations with herbicides, the reaction of seedlings to the use of chemicals, indicators of conditions and growth of conifers were also studied. Analysis of the obtained data proved the possibility of combining a protective chemical pretreatment with herbicides and planting seedlings in a single technological procedure or planting seedlings within a few months after chemical treatment, which significantly reduces the risk of damage to seedlings by herbicides. The survival rate of plantations created by planting one- or two-year-old seedlings with closed roots was 93–98 %; and the biometric indicators were such that spruce plants could successfully compete with undesirable vegetation. The application of the developed method ensures a substantial reduction in labor and other reforestation costs compared to traditional technologies involving preliminary mechanical tillage and subsequent agrotechnical weeding of plantations. For citation: Egorov A.B., Postnikov A.M., Bubnov A.A., Pavluchenkova L.N., Partolina A.N. Cultivation of Spruce Plantations Using Modern Herbicides without Agrotechnical Weeding. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 9–23. DOI: 10.37482/0536-1036-2021-3-9-23