Vol 30, No 3 (2026)

Data from 19 trial plots of the spruce stands in the Moscow region are presented. A three-parameter Weibull equation and the method of moments for parameter recovery were applied to create a model of the diameter distribution of Norway spruce (Picea abies) trees in stands damaged by the European spruce bark beetle (Ips typographus). The analysis employed descriptive statistics methods (calculation of midpoint distribution) and regression analysis. Consistency was revealed between the descriptive statistics of diameter distribution series for the entire stand and for severely weakened, dying, and dead trees, indicating the feasibility of their combined use for creating a generalized model. The input taxational variables for the model are the root mean square diameter and the average condition category. Based on these, the prediction of the diameter distribution of the total number of trees (condition categories 1–5) and separately for severely weakened, dying, and dead trees (condition categories 3–5) is demonstrated. It was established that the distribution of trees in condition categories 3–5 reflects the structure of pathological dieback, which allows for the estimation of sanitary and forest health measures (selective and clear sanitary felling) in spruce stands.

This study presents the analysis results of the component composition of the dwarf birch secondary phloem using a know-how method for analyzing lignocarbohydrate raw materials and enzyme preparations: amylases, pectinases and cellulases. Reliable data have been obtained on the content of the following components in the secondary phloem of dwarf birch: cellulose, hemicelluloses, lignin, pectin substances, starch, extractive substances (soluble in water and ethyl alcohol). The results obtained were compared with literature data on the component composition of the secondary phloem of the representative of the genus Betula of the temperate zone — silver birch (Betula pendula). Comparison of the component composition of the Birch genus from different climatic zones made it possible to determine the biochemical pathways of the dwarf birch adaptation to the climatic conditions of the tundra zone, which are characterized by high insolation, low temperatures during a short growing season, the presence of permafrost and low precipitation. A relatively high content of starch, lignin, pectin and extractives was found. An assumption has been made about the mechanism of formation of the detected differences based on modern ideas about plant physiology. Based on data on the component composition of secondary phloem, the nutritional value of dwarf birch secondary phloem as a fodder crop for reindeer husbandry was assessed.

The article presents findings on the effectiveness of low temperature, reduced illumination, and the use of the growth retardant chlorocholine chloride (CCC) for in vitro deposition of Heuchera and ×Heucherella cultivars considered promising for landscape design. Six cultivars were examined: ‘Cherry Cola’, ‘Dew Drops’, ‘Midnight Rose Select’, ‘Pistache’, ‘Grape Soda’ and ‘Plume Cascade’. Two storage experiments were conducted: medium-term (10 months) and short-term (6 months). For medium-term storage of Heuchera cultivars over 10 months, the optimal conditions were 1/2 Murashige and Skoog medium supplemented with 40 g/L sucrose and 0,1 mg/L 6-benzylaminopurine, maintained at 15 ± 2 °C under a light intensity of 65 lux. Under these conditions, the viability of regenerants reached 54,4 %. After storage, 73,3…95,0 % of the plants retained the ability to regenerate, depending on the cultivar and storage conditions. The results indicate that cultivar-specific characteristics significantly influenced regeneration success following medium-term deposition. For short-term deposition of Heuchera and ×Heucherella cultivars, the most effective conditions were 1/2 Murashige and Skoog medium supplemented with 40 g/L sucrose and 0,3 mg/L 6-benzylaminopurine, at 8 ± 1 °C with a light intensity of 40…50 lux. Under these conditions, regenerant viability was 100 % across all cultivars and experimental variants. Furthermore, regenerative activity after short-term deposition remained at 100 % and was not affected by the genetic background of the cultivars.

The article is devoted to the history of the development of wood and other plant raw materials hydrolysis methods. Booth experimental and industrial methods of wood hydrolysis with concentrated and dilute acids are presented against the background of the development of their equipment and the quality of finished products. Chemical and biochemical methods for processing wood hydrolysates into furfural, xylitol, xylitane, ethanol and protein concentrates are considered. The need to revive this wood processing industry is noted and ways of its development are outlined. This article is the seventh in the series «Wood as a chemical raw material. History and modernity». Previous parts were published in the Lesnoy vestnik / Forestry Bulletin magazine in 2022–2023.

High-quality processing of wood and wood material consists in obtaining surfaces that meet the requirements of roughness. Surface roughness affects many technological and operational properties of parts and products made of wood and wood-based materials. The consumption of adhesives and paints is associated with surface roughness in woodworking, which affects the technical and economic efficiency of many technological operations. Of particular importance is the regulation of surface roughness of parts and assemblies of wood products and wood materials in modern woodworking industries, as one of the necessary prerequisites for a rationally organized technological process. A strictly scientific approach to solving many issues of technology is possible only taking into account the roughness of the treated surface of wood materials, quantified by the values of well-defined parameters. The matter of normalizing the surface roughness of wood materials has been intensively developed to control the height of irregularities formed as a result of mechanical processing. The state of study of the issues of assessing the height parameters of anatomical irregularities has lagged significantly, since it was believed that this type of irregularity is inherent in wood and justified by the natural factor of origin. It is impossible to get rid of and influence them during processing, which means that it is not necessary to regulate them in height. Although it is known that when determining the height of machining irregularities, it is necessary to carry out measurements on areas of the controlled surface where anatomical irregularities are less noticeable. It is almost impossible to fulfill this condition, since the anatomical elements permeate the entire wood substance, including the surface layer. Therefore, in the process of measuring the irregularities of mechanical processing, elements of anatomical irregularities are always captured to one extent or another, which distorts the result obtained. In this paper, we propose a system of interconnected roughness parameters that allow us to simultaneously control the irregularities of mechanical processing and irregularities of anatomical origin. For this purpose, the roughness parameters proposed by GOST 7016–2013 are used: R_m, R_p, R_k, R_v. Of these, the R_m parameter is the sum of the other three given roughness parameters. The linear dependences of each of the roughness parameters on R_m were obtained, which made it possible to distinguish between roughness and anatomical irregularities in height. It is proposed to use a parameter representing the sum of R_p and R_k to evaluate the irregularities of mechanical processing, and the R_v parameter for anatomical irregularities. The results obtained can later be used to develop roughness standards for parts and assemblies of wood products and wood materials, taking into account irregularities of anatomical origin.

The article presents a method for smooth conjugation of two crossing straight lines with an arc of a cubic circle, which serves as a theoretical base for designing the axis of a timber road on rough terrain. The existing method of separate design of the road axis plan and profile, which is intended for use on relatively flat terrain, has been analyzed. It has been shown that this method does not provide the possibility of taking into account the entire set of geometric requirements for the axis of the route in sufficiently rugged terrain or terrain consisting of karstlands (swamps, water sources, protected forest areas with valuable or rare tree species). The same exceptions include roads in mountainous areas designed as highway spirals. Therefore, the calculation of geometric parameters of the baselines components as arcs of the spatial curve of the minimum, i.e. third order, is presented. It is noted that the curve should be circular, as having the property of smoothly changing the values of the first and second derivatives (angular coefficients of tangents, radii of circles of curvature along the arc of the curve).