Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis

One of the main consumers of microcrystalline cellulose (MCC) is the pharmaceutical industry, where MCC is used as a binder and filler in direct compression of tablets. MCC is produced by acidic hydrolysis of cellulose, which usually results in a decrease in whiteness. This is due to the destruction of sugars formed during hydrolysis and the subsequent formation of colored products. The composition and properties of these products depend on the method of hydrolysis, acid concentration, temperature, and process duration. One of the most promising methods for producing MCC is gas-phase hydrolysis of cellulose with hydrogen chloride gas-air mixtures. The method has a high rate of hydrolysis, low reagent and energy consumption. The requirements of the pharmaceutical industry determine the need to produce MCC with high whiteness. The research purpose is to select bleaching modes for MCC using sodium hypochlorite and hydrogen peroxide as bleaching agents. MCC produced by gas-phase hydrolysis of bleached wood pulp was used during the study. The whiteness and intensity of the yellow tint of MCC in the bleaching process were determined by digital colorimetry on a flatbed scanner. The paper shows that sodium hypochlorite and hydrogen peroxide allow achieving the whiteness not less than 90 % and the intensity of the yellow tint not more than 3 standard units. High-quality bleaching can be carried out even for MCC samples with an initial whiteness of about 40 %. The most effective bleaching agent is sodium hypochlorite when the pH of the bleaching solution is 2–3. Hydrogen peroxide also provides high whiteness of MCC at pH of 10–11. However, the consumption of active oxygen (AO) for bleaching is more than three times higher in comparison with the consumption of active chlorine (ACh). It was found that the dyes of MCC produced by gas-phase hydrolysis consist of two chromophore groups that decolorize at different rates. The easily oxidized group of components makes up about 90 % of the total amount of dyes, and the resistant to oxidation components make up about 10 % and determine the intensity of the yellow tint of MCC. The modes of bleaching MCC with sodium hypochlorite and hydrogen peroxide to product samples with whiteness comparable to that of imported samples were determined. For citation: Sizov A.I., Pimenov S.D., Stroiteleva A.D., Stroiteleva K.D. Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 173–183. DOI: 10.37482/0536-1036-2021-6-173-183

Stem Volume Tables by Height Classes of Willow Trees in the Northern Taiga Region of the European Part of the Russian Federation

In order to improve the accuracy of forest inventory works, tables of stem volume by height classes of willow trees in the northern taiga region of the European part of the Russian Federation were created. Forest inventory standards have not previously been developed for this species in the northern taiga region. The analytical technique proposed by I.I. Gusev in 1971 for spruce forests of the European North was used in compiling the height class volume tables. It was later adopted for the description of other tree species as well. Diameters and heights of trees were measured at 41 sample plots laid out in the Verkhnyaya Toyma and Arkhangelsk forestries of the Arkhangelsk region; 105 model trees were sampled. In most cases, sample plots were laid out in mixed plantations with the predominance of willow. The data obtained on the sample plots served to determine the parameters of the height class scale. The information source for stem volume of willow trees used to be the stem volume tables for aspen trees. A comparative analysis of the tables compiled for willow trees stems with the tables for aspen taken from the Forest Valuation Handbook for the Northeast of the European part of the Russian Federation was carried out. The analysis shows significant discrepancy in the scales for willow and aspen. The use of aspen height class volume tables for willow leads to a systematic overestimation of wood volumes. Tables of stem volumes by height classes of willow trees are used to determine stand stock with the enumeration data by 4-centimeter diameter classes. The developed tables meet the forest practice requirements. The volume tables by height classes are used to calculate timber reserves when laying out sample plots; to determine the damage level in case of stand damage; and for other practical purposes. For citation: Paramonov A.A., Tretyakov S.V., Koptev S.V., Bogdanov A.P., Tsvetkov I.V. Stem Volume Tables by Height Classes of Willow Trees in the Northern Taiga Region of the European Part of the Russian Federation. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 69–78. DOI: 10.37482/0536-1036-2021-6-69-78

Interrelations of Wood Physical and Mechanical Properties and Patterns of Their Change within the Birch Stem

The physical and mechanical properties of standing wood are not constant along the tree height and diameter. They also differ depending on the tree species and conditions of its growth. So, the research purpose is to identify patterns of change and interrelations between the parameters of density, compressive strength and sound propagation velocity along the wood fibers inside the stem of a birch tree growing in the forests of the Middle Volga region of Russia, where such research had never been conducted before. The work was carried out on two sampling areas laid out by standard methods in birch forests of natural origin with average productive capacity on the territory of the Scientific-Experimental Forest District of the Volga State University of Technology in the Mari El Republic. The average age of the birch trees is about 70 yrs, breast height diameter is 30 cm, and height is 28.5 m; 14 sample trees were studied; 0.5 m long chucks were cut out from their stems at a height of 1.3 m from the butt end and at relative heights of 0.25H, 0.5H, and 0.75H. Experimental work was carried out in a laboratory environment with modern technical facilities using standard procedures. Mathematical models describing the changes in the parameters stated above and the interrelations between them with regard to the stem diameter at relative heights were obtained. The research results generally confirmed the findings of other researchers on densitograms and other physical and mechanical properties of wood within the tree stem. However, the features listed above were revealed for birch trees growing under such conditions; in particular, it concerns the ratio of strength and density, as well as the wood strength and the velocity of sound propagation through the fibers. The results obtained have both scientific and practical value as a basis for the development of a non-destructive method for predicting technical properties of standing wood as well as timber for producing assortments for special purposes. For citation: Fedyukov V.I., Chernov V.Yu., Chernova M.S., Tsoy O.V. Interrelations of Wood Physical and Mechanical Properties and Patterns of Their Change within the Birch Stem. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 150–159. DOI: 10.37482/0536-1036-2021-6-150-159

Highly Productive Pine Forests in a Changing Climate

Forest steppe of the Central Chernozem Region (CCR) of Russia belongs to the zone of highly productive pine forests. In 2015, for the first time a partial destabilization of Scots pine (Pinus sylvestris L.) was recorded within the territory of the CCR. It affected the population, organism and cellular levels of Scots pine (Pinus sylvestris L.). The destabilization was caused by the 8-year heatwave of 2007–2014 followed by a sharp drop in the water table and four severe droughts (2007, 2010, 2012, and 2014). The analysis was carried out on two sites of pine forest plantations growing in the environmentally sound region: the Stupino test site (Voronezh region, typical plantation for the CCR) and the Usman site (Lipetsk region, lands with elevated groundwater level). The results of morphological, cytogenetic and biochemical studies of model trees of the Stupino test site during the following periods are presented: 4 optimal years in terms of weather conditions, 2014 drought year and 2015 destabilization year. It was found that prolonged hydrothermal stress resulted in the transition of pine from the basic equilibrium state to a slightly nonequilibrium state. The trigger mechanism for changing their vital state was a severe autumn soil drought in 2014, after which the plants became weakened right before winter. A decrease in cone bioproductivity by the traits of seed fullness and the total number of seeds per cone, a change in population sampling structure, an increase in the number of mitosis pathologies, and an increase in proline content in needles were observed despite optimal weather conditions in 2015. The recovery of species was studied for three subsequent optimal years on the example of the Stupino and Usman populations. Experimental data indicate that the processes of vital state normalization involve profound changes in metabolism and require certain energy expenditures. It took the Stupino population longer to return to the regional norm, which indicates a different depth of destabilization of the tree genetic material of the studied populations. For citation: Kuznetsova N.F., Klushevskaya E.S, Amineva E.Yu. Highly Productive Pine Forests in a Changing Climate. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 9–23. DOI: 10.37482/0536-1036-2021-6-9-23

Variability in Elemental Composition of Conifer Tree Rings

Distribution of chemical elements in tree rings bears important information on various biogeochemical processes. In order to achieve a reliable interpretation of the information, it is necessary to know the degree of variation in the content of chemical elements both at the level of the entire species and at the level of individual trees. The research aims to determine which chemical elements have a stable distribution in the trunks of a number of conifers: Siberian spruce (Picea obovata Ledeb.), Scots pine (Pinus sylvestris L.), Siberian larch (Larix sibirica Ledeb.), and Siberian pine (Pinus sibirica Du Tour). The data for the analysis were obtained on the basis of the long-term experiment in forest growing. The experimental site was laid out in 1971–1972 in the vicinity of Krasnoyarsk by the staff of the Sukachev Institute of Forest of the Siberian Branch of the Russian Academy of Sciences. Before planting the seedlings, the soil ground was mechanically levelled, and thus, sufficiently equal growth conditions were created for all plantings. Cores with a diameter of 12 mm were sampled from three normally developing trees of each species and analyzed using modern X-ray fluorescence methods. Content relative values of elements (counts) were obtained with the Itrax Multiscanner (COX Analytical Systems). The content of elements in the tree rings was characterized by the concentration and reserve of elements. Concentration was calculated as the number of counts per 1 mm2 of the ring area; reserve was calculated as the number of counts over the entire ring area. Each of these variables was defined by the parameters of linear slope in the calendar year series and the standard deviation. The cluster analysis was performed in the 4-dimensional space of the obtained parameters. This allowed determining whether the series of element distributions from different trees and species are grouped. Three elements (Ca, Co, and P) show high stability of distribution parameters in tree rings with no regard to tree species. A number of other elements (Mn, Pb, Cl, Cr, Ni, Sr, and W) are stably grouped depending on the species. The results of the research enable to focus on the study of the elements stably distributed in the conifer trunks. For citation: Gavrikov V.L., Fertikov A.I., Sharafutdinov R.A., Vaganov E.A. Variability in Elemental Composition of Conifer Tree Rings. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 24–37. DOI: 10.37482/0536-1036-2021-6-24-37

Modeling the Interaction of Forest Machines with Soil when Working on Slopes

The urgency of the task of effective development of cutting areas on the slopes of mountains, hills, and hilly-ridge reliefs is primarily due to the depletion of available, special, lowland operational forests in Siberia and the Far East, which were once, not quite correctly, called forest-surplus regions of the Russian Federation. The operational woodlands that are convenient for development in Siberia and the Far East are largely depleted. To develop new ones, large-scale road construction is necessary, which requires significant financial expenses and reduces the already low profitability of logging production. It is also declining due to the ever-increasing volume of export of harvested timber, even if the cost of construction and maintenance of a new network of logging roads is not considered. Forest ecosystems located on slopes are among the most vulnerable. When working on the slopes with traditional systems of logging machines, it becomes necessary to cut a serpentine of skid trails, which later become concentrators of water and wind erosion. Currently, leading manufacturers of machinery and equipment for the forest industry, such as Ponsse, John Deer, Komatsu, and others, have developed technical solutions that significantly facilitate the operation of forest machine systems. Such solutions, first of all, include winches integrated into the transmissions of machines. Another solution is to use separate self-propelled winches remotely controlled by the operator of a forest machine, for example, T-winch. In this case, the machine does not receive additional weight from the winch integrated into it; however, the negative impact of forest machines on soils does not disappear, but has its own significant specifics. The article shows that when performing logging operations on slopes, primarily steep ones with slope angles exceeding 20–25°, it is necessary to make adjustments to the assessment of the destruction nature of the soil array and the patterns of the track depth formation under the influence of the skidding system. For citation: Rudov S.E., Shapiro V.Ya., Grigorev I.V., Kunitskaya O.A., Grigoreva O.I. Modeling the Interaction of Forest Machines with Soil when Working on Slopes. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 121–134. DOI: 10.37482/0536-1036-2021-6-121-134

Producing Planting Material of Rubus arcticus L. by Clonal Micropropagation

The article presents the results of experimental studies on various propagation methods of the Arctic bramble in the Kostroma region. Industrial cultivation of forest berry plantations is a possible effective solution to the problem of low profitability of using nontimber forest products, reduction of the wild berries resources and their productivity and quality, and reclamation of cutover peatlands. It is advisable to use high-yield varietal planting material to create such plantations. Special attention is paid to propagation and production of healthy planting material using culture of plant cells and tissues. Data on sterilization of explants when introduced in vitro are given. The highest efficiency of sterilization was observed when using a chlorine-free eco-sterilizer (the plant survival rate on the MS nutrient medium was 90–93 %). The effect analysis of the passage number of regenerated plants on the multiplication factor of the Arctic bramble varieties was carried out. The optimal concentrations of cytokinins at the stage of micropropagation are shown. The largest number of the Arctic bramble roots was observed when adding 1.0 mg/L of Indole-3-butyric acid (IBA) and 0.5 mg/L of Ecogel to the nutrient medium. The technological and agrotechnical operations performed during the cultivation of planting material of forest berry plantations are considered. Data on the coefficients of vegetative propagation of plants and their resistance to diseases, yielding capacity, and recultivation of cutover peatlands are given. The best planting material of the Arctic bramble are ball-rooted seedlings. Sawdust and sphagnum were used in the cultivation of this berry on the peatland. The economic efficiency of its cultivation with the method of clonal micropropagation was 358.2 %. For citation: Makarov S.S., Tyak G.V., Kuznetsova I.B., Chudetsky A.I., Tsaregradskaya S.Yu. Producing Planting Material of Rubus arcticus L. by Clonal Micropropagation. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 89–99. DOI: 10.37482/0536-1036-2021-6-89-99

Forest Management Assessment of Biodiversity in the Taiga Zone

The need to preserve biodiversity has been recognized for decades, even centuries in North America, Europe and some other regions of the world. importance of preserving species and wildlife areas is emphasized in many cultures. Preservation of biodiversity in forest management, and especially in industrial logging, is one of the most important tasks of modern forestry. In many countries with the developed forest complex (Finland, Sweden, etc.), the task of preserving natural biodiversity has the same priority in the state forest policy as providing the forest industry with wood raw materials. The main requirements for the biodiversity preservation in Russia are enshrined in the National Standard (Forest Code of the Russian Federation, article 1) governing Voluntary Forest Certification. Organization of forest management in the Vologda region is carried out with consideration of significant aspects of biodiversity preservation. The research purpose is the forestry and economic assessment of biodiversity at the local level in the taiga zone (case study of the Vologda region). The assessment was carried out based on the inventory characteristic obtained in the field studies. The methodological provisions of E.A. Rai and S.I. Slastnikov were used to perform economic assessment of the preservation of key objects. A comparison of the costs of timber logging in biotopes and the income from its sale (in the case of logging stands in key biotopes with the subsequent sale of the resulting timber) showed significant differences between the objects under consideration. It is shown that according to the assortment structure, a significant part of the studied biotopes accrue to firewood. The cost of timber varies from 9.6 to 529.5 ths rubles. The amount of costs at different sites will vary significantly from 9.0 to 340.5 ths rubles due to the possible cutting of key biotopes. At the same time, a negative financial result is observed only at one site (a forest site with a habitat of Neckera pennata, which is included in the Red Data Book of the Vologda Region). The results demonstrate that the allocation of key sites and their further preservation is environmentally sound, but in some cases (when compared with the income from their cutting) is not commercially justified. For citation: Korchagov S.A., Khamitov R.S., Gribov S.E., Ivanova M.G., Belyakov D.V. Forest Management Assessment of Biodiversity in the Taiga Zone. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 110–120. DOI: 10.37482/0536-1036-2021-6-110-120

Synthesis of Colloidal Silver Using Lignosulfonates

Colloidal silver solutions can be used as catalysts for carrying out various chemical transformations of organic substances and solving the problems of disposal of toxic compounds, as well as antibacterial agents for combating pathogenic microflora, in the manufacture of lubricants and light-absorbing materials, coatings, sensors, conductive pastes, and high-performance electrode materials. The research purpose is to study the synthesis of colloidal silver using a solution of technical lignosulfonates (LST) as a stabilizer. Colloidal silver was synthesized as a result of the reduction-oxidation (redox) reaction of Ag(I) cations with glucose at 100 °C in the presence of lignosulfonates. The reaction was carried out in an alkaline medium, which is provided by the addition of ammonia water. Electronic spectroscopy was used to control the synthesis of colloidal silver. After the reaction, the solution turned dark brown and an intense absorption band with a maximum at 400 nm appeared on the electron spectra. The effects of reagent consumption and synthesis duration were studied. It was found that the optimal reagent consumption in the colloidal silver synthesis is as follows: 2.5–5 g glucose / g Ag, 0.3–1 g LST / g Ag, and 3–5 g NH3 / g Ag. The synthesis duration is 2–5 min. The resulting colloidal silver solution is stable for several months. Partial stratification without precipitation is observed during the solution storage. It is shown experimentally that the stratification is followed by a redistribution of colloidal silver particles. Electron spectroscopy confirmed the absence of colloidal silver particles in the upper layer. The reaction kinetics has been studied in experiments carried out under thermostatically controlled conditions at temperatures from 50 to 100 °C. The kinetic dependence is described by a first-order equation at the initial stage of the reaction, the duration of which depends on the temperature. The duration of the active part of the kinetic curves is 15–90 % of the total reaction time. The logarithm of the rate constant on the active section was proved to depend linearly on the reverse thermodynamic temperature (pair correlation coefficient is 0.9887). The activation energy was 47 kJ/mol. For citation: Plakhin V.A., Khabarov Yu.G., Veshnyakov V.A. Synthesis of Colloidal Silver Using Lignosulfonates. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 184–195. DOI: 10.37482/0536-1036-2021-6-184-195

Evaluation of Siberian Stone Pine Plantations at the End of the First Age Class

The 40-year-old plantations of Siberian stone pine laid out as a permanent seed plot have been studied. The research purpose is to study the integrity, state and main forest inventory parameters of the Siberian stone pine plantations on the southern line of the species range at the end of first age class; to determine the role of natural renewal of trees and shrubs on the development of the Siberian stone pine plantations; to improve process solutions for efficient renewal of high-value biological resources. The research uses the methods generally accepted in forestry, forest science and forest inventory. It is found that the integrity of Siberian stone pine on the site is about 31 % (678 pcs/ha), wherein 406 pcs/ha are without damage to the trunk. Only about 25 % of Siberian stone pine trees grow under low shade, the rest of them are constantly shaded by natural renewal and have varying degrees of suppression. No generative organs were found in 44-year-old Siberian stone pine trees. At the initial stage of plantations growth, the main factor negatively affecting the integrity and state of trees is the damaging of Siberian stone pine by moose. Traditional improvement thinning with leaving stumps that produce many shoots of deciduous species attracts moose to the site in winter, where they use young growth of deciduous species and the covered with needles part of Siberian stone pine as forage. Subsequently, in the absence of tending, natural renewal negatively affects the Siberian stone pine trees, inhibiting growth and formation. It is necessary to remove the negative influence in the mixed biocenosis in order to prevent further deterioration of the Siberian stone pine state. This requires completely different technological solutions for forestry activities such as ringing or injection of trees of natural renewal, causing drying at the root, which significantly reduces or eliminates the emergence of deciduous young growth. This will decrease the attractiveness of the site for moose and minimize their impact on Siberian stone pine. The clear drying of surrounding trees will enhance the illumination of Siberian stone pine crowns and improve their soil nutrition, ensuring good root, trunk, and crown growth and accelerating the beginning of the formation of generative organs. These technical solutions can be used throughout the forest zone for the artificial cultivation of the high-value species – Siberian stone pine. For citation: Terekhov G.G., Andreeva E.M., Stetsenko S.K. Evaluation of Siberian Stone Pine Plantations at the End of the First Age Class. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 56–68. DOI: 10.37482/0536-1036-2021-6-56-68