No 6 (2025)

The article examines the features of the anatomical structure of the hydraulic system of 17 species from 13 genera of 6 families of woody flowering plants, which belong to different tiers of the floodplain forest growing along the Enmyvaam River (hypoarctic tundra). It has been found that 1st-tier trees have the most advanced hydraulic system. It consists only of libriform fibers and vascular segments of a short-cylindrical, cylindrical fibrous shape with simple perforations, punctate alternate, closed, and close-set intervascular porosity, single-row, mostly homogeneous rays, apotracheal and paratracheal parenchyma. This is most likely due to the particularly intense water exchange regime in tall trees, whose crowns are more susceptible to harsh environmental influences. Shrubs and low-growing trees of the 2nd tier demonstrate the presence of both archaic and evolutionarily advanced features in approximately equal quantities in the stem wood. For example, in the genera Alnus and Sorbus, there is a combination of libriforms with fibrous and vascular tracheids; vessel segments with scalariform, reticulate, and simple perforations, apotracheal and paratracheal parenchyma, and heterogeneous and homogeneous palisade rays. As for the species of the genus Salix, they have a highly developed hydraulic system, similar to that of the 1st-tier plants. Small shrubs and dwarf shrubs of the 3rd tier, living in areas with excessive absolute and relative humidity and sometimes extremely low lighting, have the widest range of specific adaptive features acquired as a result of adaptation to the extreme conditions of high latitudes.

The aim of the study has been to identify the most significant soil factors of the root layer (water-physical and agrochemical) for ensuring the growth of Norway spruce. The research has been carried out in 5-year-old crops created at the mounds prepared by an excavator at the fresh cutting of blueberry-type forest in the Vilegodsky forestry of the Arkhangelsk Region. 2-year-old planting stock of Norway spruce with a closed root system (2.0 thousand pcs./ha) has been used. For 1 mound, 2–3 seedlings have been planted: in the centre, at the edge away from the hole, and at the edge near the hole formed during the preparation of the planting site. The main biometric parameters have been measured in seedlings (60 pcs.) and in similarly aged spruce undergrowth (40 pcs.) of the subsequent generation in the cutting strip. Multivariate statistics methods have been used to analyze the data. It has been determined that the most responsive to differences in growing conditions are plant height associated with growth, as well as the length of lateral roots. It has been found that, based on the similarity of water-physical and agrophysical properties in the root layer of spruce growing in the cutting strip, the central part of the planting site is closer. These conditions have also contributed to a better growth of seedlings in the centre, compared to the edges of the mound (near the hole and away from the hole). It has been established that the priority in ensuring the growth parameters of spruce in the 1st years of life largely belongs to water-physical properties, such as the mound height, porosity, solid body density, and moisture content, as well as the closely related density of soil structure and aeration porosity. At the same time, of the agrochemical indicators, only the content of potassium and phosphorus (at the trend level) have turned out to be significant. In practical terms, the results obtained make it possible to adjust the recommendations for discrete soil tillage with an excavator and the placement of planting material in planting sites. They will be useful in predicting the growth of planting material using rapid methods of soil research.

The technology for producing planting stock with a closed root system of the main forest-forming species using a multi-rotation cultivation mode is being improved. In forest nurseries of the middle taiga forest subzone of Russia with a short growing season, the introduction of such a regime is difficult due to the risk of seedlings being unprepared for transplantation to a planting area and low stress resistance. At the end of the growing season in November 2023, a comparative analysis of 1-year-old containerized seedlings of Pinus sylvestris L. was carried out under non-rotation (0rot) and 2-rotation (2rot) cultivation modes in northern latitudes. The experimental 1rotT variant has differed from the 1rot (1-rotation mode) by the use of a shade cloth. Morphometric parameters and the provision of basic mineral nutrients (N, P, and K) have been determined in seedlings. The dynamics of the index of damage to pine needle cell membranes by low temperatures in the autumn period during the transition of the plant from vegetation to dormancy has been studied. The morphometric parameters of the 2rot seedlings, with the exception of the stem diameter, have been lower than those of the seedlings of other variants and have not corresponded to the standard ones. The needles and stems of 2rot seedlings have differed from all variants in increased levels of nitrogen and potassium, as well as phosphorus in the stems compared to the 0rot and 1rotT variants. Unlike other variants, their needles have been bright green and they had not had an apical bud. The needles of seedlings of all cultivation modes in the 1st ten days of September have been resistant to low temperatures only down to –4 °C. The frost resistance of seedling needles has increased and in the 3rd ten-day period of October in all variants except 2rot the needles have not been damaged even at –25 °C. The 2rot seedlings have differed from other variants in their reduced frost resistance of needles from the 2nd ten-day period of September. Considering the possibility of frosts in the autumn period, there is a risk of damage to 2rot seedlings.

The research is devoted to the synchronization of log cutting and sawn timber drying processes. It has been shown that, given the actual number of sawn timber sections produced by large-scale sawmilling during the technological period, the buffer storage units of drying stacks of boardsdo not ensure the uninterrupted operation of the tunnels. There is either an overflow of buffer storage units with stacks, or their absence when free space occurs in the tunnels. The methods used for calculating the buffer storage units of the stacks donot take into account the probabilistic nature of the characteristics of sawmills and drying shops. Theydo not provide a mathematical description of the relationships between the rate of incoming raw sawn timber stacks, the capacity of the buffer storage unit, as well as the number and capacity of drying tunnels. The aim of this work has been to find the patterns of accumulation of sawn timber stacks in front of drying tunnels and loading tunnels with stacks, with the establishment of the average waiting time for stacks in the storage unit under different characteristics of log sawing and sawn timber drying processes. The “stack storage unit – drying tunnels” system has been presented as a multi-channel queuing system with parallel operation of channels and waiting. The main initial indicators of the system are the rate of incoming raw sawn timber stacks to the storage unit in front of the drying tunnels and the intensity of sawn timber drying in 1 tunnel. The main output operational characteristics are the probability of a full tunnel load, the average number of stacks in the storage unit, and the time the stack remains in the storage unit. The general patterns of accumulation of board stacks and filling of drying tunnels in the conditions of large-scale production of sawn timber have been established. The examples of solving practical problems of synchronizing sawmilling and sawn timber drying have been presented. It has been shown that the obtained graphs and mathematical models make it possible to solve production problems: to analyze the influence of the type and size of the sawn raw material, the structure of the sawing patterns, the feed rates of the sawmill equipment, the operating modes of the sawmill, as well as the drying modes of the sawn timber on the choice of the number of tunnels and their capacity.

Kraft lignin is the largest-tonnage technical lignin formed during kraft pulp cooking. According to statistics, approximately 70 mlnt of such waste are generated annually. Most of it is disposed of in the system of chemicals recovery and thermal energy generation. Approximately 10…20 % of kraft lignin can be used to obtain a variety of products, for example, in the production of polymers, low-molecular compounds, activated carbon production, rubber industry, etc. For this purpose, kraft lignin is subjected to various types of modifications, including chemical ones: periodate oxidation, halogenation, sulfonation, sulfomethylation, nitration, nitrosation, etc. This article presents a new method for modification of kraft lignin with nitrous acid in a water-dioxane medium using solid-phase catalysis. The cation-exchange resins in H-form containing sulfogroups (cationite KU-2-8 and wofatite) have been used as catalysts. The optimal reagent consumption has been determined to be 50 % sodium nitrite and 230 % cationite from kraft lignin. It has been shown that the developed method and the well-known one using sulfuric acid as a catalyst give similar results. The molecular and electronic spectra of modified kraft lignin have been studied. In the electronic spectra of modified kraft lignin, a new absorption band appears characteristic of the nitroso group in the region of 400…500 nmwith a maximum at 451 nm. By deconvolution, the electronic spectrum of modified kraft lignin is approximated by 6 Gaussians with an error of 2.5 %, while for the initial kraft lignin the spectrum can be described by 4 Gaussians with an error of 3.4 %. In contrast to the IR spectrum of kraft lignin, new absorption bands appear in the spectra of modified lignin at 615, 760, 1,330 and 1,550 cm–1, which are due to vibrations of NO bonds.

Currently, the task of obtaining high-quality planting stock used in reforestation remains urgent. Stimulating preparations are used to activate germination and seed germination energy. The aim of the work has been to study the effectiveness of using various stimulating preparations on the sowing qualities of Scots pine (Pinus sylvestris L.) seeds. The objects of the study have been Pinus sylvestris L. seeds soaked in solutions of preparations with a purported stimulating effect. The following preparations have been used: technical lingosulfonates, birch bark extracts, filtrate obtained by separating suberin from birch bark, Flavobacterin, Mizorin, condensate formed during the drying of sawn timber, and ash from the Eyjafjallajökull Volcano. In the experiments, several time options for soaking seeds have been adopted: 6, 12 and 24 hours. The highest germination and germination energy have been observed in seeds soaked for 24 hours. The indicators of the seed grain soaked for 6 and 12 hours have also increased compared to the control sample of dry seeds. The best germination has been observed in seeds treated with solutions of nitrosated and chlorinated lingosulfonates at a concentration of 10 % for 24 hours (95 %), the highest germination energy (86 %) has been observed in seeds soaked for 24 hours in an extract of birch bast fraction less than 1 mm (concentration 1:10,000) and filtrate from the separation of suberin from birch bark (concentration 1:10,000). In the control option, the seed germination has been equal to 80 %.