Conifers are characterized by a certain degree of individual variability in the content of stress metabolites, which can be caused by genotypic variations or divergence in the growth conditions of individual trees. The purpose of the study is to evaluate the variation of biochemical traits of Scots pine, which are different in the color of male strobilus, during adaptation to the conditions of constant excessive moisture in the soil of the northern taiga. The dynamics of metabolic parameters of Pinus sylvestris L. were investigated in shrubsphagnum pine stands on marshy upland soils at the mouth of the Northern Dvina River (northern taiga subzone). From July to November 2018, needle samples from shoots were collected from 10 pine trees of each of the male strobilus types, differentiated by color. The contents of photosynthetic pigments, anthocyanins, ascorbic acid, proline, water-soluble proteins, and pH were measured under laboratory conditions. The synthesis of chlorophyll in the needles in the current year of formation decreased in trees of both forms during the dry summer period. A favorable temperature in the autumn period could promote an extension of photosynthetic pigment accumulation, which might negatively affect tree preparation for overwintering. There were no significant differences between f. erythranthera Sanio and f. sulfuranthera Kozubow in the needle content of chlorophyll and carotenoids, anthocyanins, ascorbic acid, free proline, water-soluble proteins, or pH. The similarities in the adaptation of the trees to the constant excessive soil moisture in northern taiga conditions were revealed. The seasonal factor had a considerable impact on the dynamics of biochemical parameters. Ascorbic acid, proline, and anthocyanin were more actively accumulated in the needles throughout the summer due to the high air temperature, resulting in an increase in antioxidant activity and the development of protective mechanisms aimed at reducing oxidative stress. The increase in water-soluble protein content in needles from October to November is one of the cryoprotective mechanisms of the trees for the winter period. Individual differences in ascorbic acid and proline contents in yellow microspore-bearing pine needles at the establishment of minus temperatures in November were considerably higher than in red microspore-bearing pine needles. This is regarded as the norm of the reaction for different types of trees to the influence of negative temperatures. For citation: Tarkhanov S.N., Pinaevskaya E.A., Aganina Y.E., Pakhov A.S. Variability of Biochemical Properties During Adaptation of Pinus sylvestris (Pinaceae) Forms to Excessive Moisture Conditions. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. 58–75. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-58-75
The productivity of the wood grinding process can be increased by using abrasive wheels with spherical corundum grains. They also expand the area of application of rigid abrasive instruments by reducing soiling and eliminating burns on the treated surface. The studies revealed several advantages of the abrasive wheels over sanding paper: very precise processing, achievement of the desired grade of the treated surface, high durability of the instrument, and low cost. A force analysis of a grinding surface with micro-cuttings made of spherical corundum grains was performed depending on the degree of its wear. The results revealed that chip removal by the spherical corundum grains was possible only under certain conditions when the cutting edges of the grains were exposed. Besides, the theoretical dependencies of forces in micro-cutting were obtained from every principal condition for the process of grinding wood and wooden materials: properties of the spheres, treatment modes, and material-related factors. The special properties were analyzed by the chip formation process and self-sharpening conditions of the spherical corundum wheels. The grain size had the greatest influence on the thickness of chips which were cut by one grain. The grain content and bonding, like other properties of the internal volumetric structure, had a less substantial impact. The abrasive tool characteristics must complement the processed material, such as grain size, hardness, and structure. On the other hand, spherical corundum has optimal physical and mechanical properties for grinding, particularly the thickness of the grain’s edges, which primarily determine the material’s tensile strength. The grinding depth and feed rate mostly define the parameters of the grinding performance of wood and wood-based materials. An increase in those leads to a rise in cutting forces, roughness of the ground surface, a reduction in the grinding length over the period of the wheel’s durability, and the grinding coefficient. If the grinding depth and feed rate are constant, the performance can be improved by increasing the cutting rate. For citation: Sergeevichev A.V., Sokolova V.A., Mikhailova A.E., Ovcharova E.O., Voinash S.A. Force Analysis of a Single Grain Cutting Process in Wood Grinding Using Spherical Corundum. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 140–154. (In Russ.). https://doi.org/10.37482/0536-1036-2023-3-140-154
The article studies the intraspecific response of European spruce (Picea abies (L.) Karst. × P. obovata (Ledeb.)) to climatic changes on the basis of data on the growth of 15 provenances in 31-year-old provenance plot of the North Russian Plain (Arkhangelsk and Vologda regions) simulating warming and cooling. We compared the actual height and diameter at the test site and the calculated height at the places of growth of the source stands, determined by recalculating the actual progeny growth data through the latitudinal growth coefficients proposed by I.V. Volosevich for the North Russian Plain. The difference between the calculated and actual growth rates of the corresponding provenance at the test site represented the response of the provenance to the change in growing conditions. The response was crosschecked with differences in climatic characteristics (sum of effective temperatures above 10 °C) and geographic coordinates of the places of origin and growth of spruce. Spruce has approximately the same response rate if offspring move by an equal amount of gradient (north latitude) to the south or to the north and if the climatic factor (sum of temperatures above 10 °C) changes towards warming or cooling. While the sum of temperatures changes above 10 °C for every 100 °C, the difference in growth in height and diameter will be 0.48 m and 0.42 cm, respectively; for each degree of change in northern latitude, on average, 0.50 m and 0.44 cm in height and diameter, respectively. However, for species from the northern taiga subzone, mainly represented by Siberian spruce (P. obovata) the response of the species will be half as much than for the origin of hybrid spruce (Picea abies (L.) Karst. × P. obovata (Ledeb.)) from the middle taiga subzone. The calculated values of response by height and diameter for European spruce should be considered when regulating seed transfer and used in forecasts for the adaptation of forestry measures to the expected climatic changes.
The predominance of mixed forest stands in a productive forest fund, which is located in the middle taiga subzone of Northwest Russia, determines the relevance of an investigation of the growth and development characteristics of the trees. In secondary stands, created by an extensive human consumption of primary spruce stands, spruce trees are generally presented in a minor quantity. The recovery of their dominance is an urgent economic and ecological issue. Despite the unity of approaches concerning the maintenance of deciduous-spruce forests, the research characteristics on the structure of the root systems differ considerably along with age and geographical position. This article investigates a root system competition between spruce and deciduous species in a 70-year-old blueberry-type forest that was 100 thinning by a reconstructive cutting 35 years ago. The mass of fine roots and their distribution in the upper solid layers were examined by the method of soil monoliths in the mixed stands with different proportions of spruce. The numerical characteristics of the stands were determined by the results of a regular complete enumeration on the trail plots. Besides, the tree diameters were measured around the circular plots, which were made for the collection of the monoliths. The records were made on the dynamics of changes in forest floor thickness and vegetation. The relationship between the underground and elevated parts of the stands was explored. It was shown that the roots of spruce can occupy the same ecological niche as the roots of deciduous species. A correlation analysis revealed a statistically significant relationship between the mass of fine spruce roots and the competitive influence of deciduous species, the proportion of spruce in the stand, and its current volume increment. There was a significant difference in spruce root mass under joint growth with birch and aspen. Therefore, it was concluded that this phenomenon has a complex nature. Namely, the mass of the spruce roots has a direct dependency on their closeness to the maternal trees in combination with the spatial heterogeneity of the organic soil layers. The gained findings are important for the regulation of the composition and structure of the mixed deciduous-spruce stands for growing sustainable stands with a high economic value. For citation: Karpechko A.Yu., Sinkevich S.M. Influence of Reconstructive Cutting in Deciduous-Spruce Stands on Root Competition of Species. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 99–112. (In Russ.). https://doi.org/10.37482/0536-1036-2023-3-99-112
The efficiency of a stationary circular saw is determined by the performance and operational reliability of the woodcutting unit. During operation, the circular saw blade is exposed to a variety of complex loads and thermal conditions. The rigidity and stability of the saw blade determine its capacity to resist the perturbing cutting forces. The cutting compound itself is a thin disc made of steel with a hole in the middle that has a serrated cutting edge. It consists of three areas: peripheral, middle, and central. The stability of the saw blade is determined by the middle and peripheral parts. The increase in durability is achieved by plastic deformation to form the strip boundaries of the radial sections. These parts are treated by forging in both national and international practice. Normalization of loads on the blade in case of local mechanical contact with the working body is formed in the strip boundaries of the radial sections through the formation of places with plastic deformation of the metal, which rearrange the loads and place them in the radial direction. At the same time, countertension appears from the adjoining sections, leading to mutual “repulsion” of them and the creation of compressive tension that compensates for the forces of centrifugal acceleration, thermal heating of separate areas of the saw blade, external longitudinal and transverse bending tension that arise during wood processing. The combined interaction of all adjoining sections provides the tension and stability of the saw blade. The creation of the radial sections by forging has some significant disadvantages. Their elimination requires a fundamentally new approach, such as the formation of the residual stress sections in the saw blade by thermal exposure. It creates a normalized residual thermoplastic tension in the saw blade by a short-time (1–2 s) focused thermal influence on the strip boundaries of the radial sections. The results of the conducted research determined the boundaries of the sections for thermal treatment and the temperature range, which ensure the formation of normalized residual thermoplastic tension in the circular saw blade through concentrated pulsed heating of the strip edges of radial sections. For citation: Melekhov V.I., Solovev I.I. Formation of Sectoral Residual Thermoplastic Tension Fields in Circular Saw Blade. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. 146–154. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-146-154
