No 2 (62) (2024)
Editor’s note
5-5
FORESTRY
Disinfection of substrates for growing containerized tree seedlings
Abstract
Introduction. Production of ball-rooted planting stock compliant with relevant standards suggests the use of a quality root covering substrate during growing. The substrate must be characterized by the optimal physicochemical properties, absence of weed seeds and pathogenic microflora. Electromagnetic fields of ultrahigh frequencies are proposed to be used as an alternative method of disinfection.
The purpose of the work is to determine an effective mode of disinfection of root covering substrates in an ultrahigh frequency electromagnetic field (microwave EMF).
The object of the study was lowland peat modified with weed seeds. The experiment involved a quantitative analysis of the colony-forming units (CFUs) of microorganisms in the peat, as well as studying the germination capacity of weed seeds and the biometric parameters of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) seedlings. The effects of microwave radiation on the changes in the peat temperature and mass were investigated.
Results. The analysis of the peat heating temperature variations depending on the microwave radiation mode showed that the intensity of peat heating depends on the power and exposure time of irradiation. The effective heating temperatures of 100-120° C were recorded at power levels of 600-800 W, with an exposure duration of 8-10 minutes, as well as at 450 W, with a 10-minute exposure. The minimum loss of the peat mass due to microwave irradiation was observed at power levels of 300-450 W, with an exposure time of 10 minutes. The study of the impact of microwave fields on microorganisms revealed both suppressive and stimulating effects of irradiation applied under different modes. The analysis of the results of the experiment on the effects of microwave radiation modes on the germination capacity of weed seeds found a total absence of weed seedlings when applying irradiation at a power of 200–450 W for 4–8 minutes. Scots pine seedlings grown on peat pre-treated with microwave irradiation exhibited an increase in the weight of seedlings as compared to the control. In Norway spruce seedlings, the germination energy of seeds decreased, while the root collar diameter significantly increased.
Conclusion. The optimal mode of peat sterilization via microwave irradiation was found to be at a power of 300 W, with the exposure time of 10 minutes. The microwave radiation modes that inhibit seed germination were determined. Peat disinfection by microwave irradiation has a positive effect on the weight of Scots pine seedlings and reduces the germination energy of Norway spruce seeds.
6-19
Influence of the macroelement composition of the WPM medium and growth regulators on the morphogenesis of vegetative and generative tissues of varietal forms of Vaccinium angustifolium Ait
Abstract
Introducion. The high demand of the food manufacturing industry for varietal forms of blueberries necessitates research on the characteristics of tissue culture of the varieties that can both serve as the basis for obtaining new cultivars through breeding and optimize the clonal micropropagation technology for valuable varietal forms of blueberries. Of fundamental importance is the issue of switching the generative tissues of microspores to the sporophytic pathway of development. The key factors determining the activity of morphogenesis of plant tissues in in vitro culture are the content of macroelements and growth regulators in the nutrient medium.
The purpose of the study is to determine the influence of some macroelements and growth regulators on the morphogenetic activity of vegetative and generative tissues in varieties of Vaccinium angustifolium Aiton (lowbush blueberry) in in vitro culture.
Material and research methods. The article deals with the issues of the tissue culture of vegetative and generative structures of Vaccinium angustifolium Ait. varieties (‘North Country’, ‘North Land’ and ‘North Blue’), as well as the influence of the qualitative and quantitative content of macroelements and plant growth regulators in the nutrient medium on the activity of morphogenesis of vegetative and generative tissues in explants. At the same time, nutrient media containing macroelements at concentrations ranging from 50 to 150 % of the McCown Woody Plant medium (WPM) composition were tested. WPM medium in its original concentration (100 %) was used as a control medium. The growth regulators of 2-isopentyladenine (2-ip) and zeatin (Zea) at concentrations of 1–4 mg/l were tested with the addition of indoleacetic acid (IAA) when working with the vegetative tissues, and 2,4-dichlorophenoxyacetic acid (2,4-D) at a concentration of 0.5–2.5 mg/l when working with the tissues of generative structures.
Results. The study revealed the specificity of morphogenesis of the vegetative and generative tissues of the studied varieties on the tested media. The activity of morphogenesis of the vegetative tissues of the ‘North Land’ and ‘North Blue’ varieties was optimal on the control medium supplemented with 3 mg/l Zea and 3 mg/l 2-ip, respectively. The shoot formation in the ‘North Country’ variety was the most intensive at 75 % WPM and 2 mg/L Zea. The viability of anther generative tissues was maximum at a concentration of 125 % of the WPM composition for all three varieties. The number of embryoids formed was the greatest with the addition of 1.0 mg/L of 2,4-D for ‘North Land’ and ‘North Country’ and 1.5 mg/L of 2,4-D for the ‘North Blue’ variety.
Conclusion. The study revealed specific features of activating the switch of the microspore development from the gametophytic to the sporophytic program in Vaccinium angustifolium Aiton varieties. The features depend on the concentrations of macroelements in the medium composition and can be controlled by growth regulators.
20-30
Pigment composition of the needles of decorative forms and varieties of Western thuja (Thuja occidentalis) in the conditions of the Nizhny Novgorod region
Abstract
Introduction. The problem of forming the assortment composition of landscape plantings in modern cities is closely related with the urgent need to stabilize the environmental parameters of urbanized territories. The composition of urban plantings includes representatives of foreign flora. These include Western thuja (Thuja occidentalis L.), varieties and forms of which are used in protective, reclamation and greenery plantings.
The purpose of the research is a comparative assessment of several decorative forms and varieties of Western thuja in terms of their needle pigment composition during their introduction to the urban plantations in the Nizhny Novgorod region.
Objects and methods of research. The objects of the research were nine varieties and one typical form of Western thuja, grown on the same experimental site in the arboretum of Nizhny Novgorod State Agrotechnological University. The principles of the only logical difference, typicality, suitability, expediency, and reliability of an experiment were observed in conducting the research. A total of 30 same-aged plants of vegetative origin were used in the study. Five shoots of the same type, age, and phenological state, without signs of damage by biotic and abiotic factors or deviations from normal development were cut off each of the thirty plants simultaneously. Plastid pigments were detected using an SF-2000 spectrophotometer equipped with the GRASS GIS 7.6.1 / QGIS 3.4 software.
Results. Varieties and form of Western thuja are heterogeneous in terms of pigment composition of their needle foliage, which was observed both at the beginning and at the end of the growing season. In terms of the chlorophyll-a content during the spring period, the highest concentration was found in the variety 'Mr. Bowling Ball' (2.51±0.06 mg/g) and the lowest was observed in the 'Sunkist' variety (0.39±0.05 mg/g). In autumn, the largest amount of chlorophyll-a (3.16 ± 0.02 mg/g) was recorded in the variety 'Danica', and the smallest (1.81 ± 0.03 mg/g) in the variety 'Rheingold'. The analysis of variance confirmed the hereditary conditionality of the noted differences for each observation period.
Conclusions. Under the conditions of introduction to the Nizhny Novgorod region, the pigment composition of the needles of the ornamental varieties and typical form of Western thuja is seasonally unstable and subject to significant changes in terms of the content and ratio of chlorophyll and carotenoids at the beginning and at the end of the growing season, though their concentrations increase in autumn.
31-45
TECHNOLOGIES AND MACHINES OF FORESTRY
Physical and mechanical properties of wood-cement composites based on log rounding waste
Abstract
Introduction. Obtaining high-quality, eco-friendly and cost-effective building materials is the main task of researchers and construction organizations. The key element of cost reduction is the use of cheaper raw materials. In the manufacture of wood-cement composites, deadwood can be the basic raw material for producing the filler. The natural drying of deadwood under the influence of external factors leads to the degradation of harmful compounds, but, at the same time, the wood loses its properties and becomes susceptible to rot and pest attacks.
The purpose of the research is to study the physical and mechanical properties of wood composite materials incorporating log rounding residues, as well as to compare these properties with the requirements specified in the standards for using these materials for constructing low-rise buildings.
Results. The study revealed the physical and mechanical properties of arbolite filled with the log rounding waste obtained from deadwood and sound wood. The test results showed that arbolite containing deadwood log roundup waste as a filler meets the requirements of the GOST 19222-2019 standard "Arbolite and its products. Specifications". This proves deadwood applicability for manufacturing wood-cement composites.
Conclusions. In terms of its physical and mechanical properties, arbolite filled with deadwood log rounding waste and liquid sodium glass meets the requirements of GOST 19222-2019 "Arbolite and its products. Specifications". To increase the strength of the arbolite, a mineralizer in the form of liquid sodium glass or a filler made up of deadwood and sound wood in a 1:1 ratio should be added to the mixture.
46-55
Assessment of the stress-strain state of the forest road pavement reinforced with geosynthetic shells
Abstract
Introducion. Forest roads play an important role in the development of forestry. They provide access to forest expanses, which enables logging operations, timber removal, forest monitoring and research. Reduction of wood removal costs is a pressing issue for the forest sector, which can be tacked, inter alia, by cutting expenditures on the construction and operation of forest roads through the use of tread pavement. One of the options for constructing this type of road pavement is to utilize shells made of geosynthetic materials. However, the functioning of such structures has not been sufficiently investigated.
The purpose of the research is to study the stress-strain state of the geosynthetic shells as a component of road pavement by applying the numerical method.
Objects and methods. The objects of the research are geosynthetic shells designed to reinforce the road pavement base. To study their functioning, the finite element method was employed.
Results. The article presents the results of the numerical modeling of the design of a transition-type road pavement reinforced with geosynthetic shells. The studies undertaken have shown that the use of geosynthetic shells makes it possible to reduce the vertical deformation. With a shell thickness of 0.2 m, vertical movements decrease by 20–48% depending on the width of the shell, and with a shell thickness of 0.4 m - up to 59%.
Conclusion. The proposed designs of road pavements reinforced with geosynthetic shells allow for a significant reduction in the vertical deformation of the forest road pavement. The efficiency of using geosynthetic shells in transition-type pavement structures of forest roads depends on the geometric parameters of the shells.
56-63
PROBLEMS OF ECOLOGY AND RATIONAL NATURE MANAGEMENT
Assessing the ecological health of Hexi Corridor’s forest ecosystem using RSEI time series
Abstract
Introduction. This study provides an in-depth analysis of the forest Remote Sensing Ecological Index (RSEI) time series data in the Hexi Corridor area from 2000 to 2023, employing nonlinear curve fitting to uncover the changing trends and characteristics of the region's forest ecosystems.
Research Aim. Harnessing the characteristics of nonlinear curves, specific transformative periods and points within the series are identified, facilitating refined predictions for forest ecological trends. By combining the generalized additive model (GAM) to extract the different impact relationships between altitude and RSEI in different forest ecological regions, and the IncMSE analysis of the random forest model, the differences between altitude and forest type on forest ecosystems in different forest ecological regions were found Influence.
Result. Forests at higher altitudes exhibit greater ecological stability and elevated RSEI values, suggesting improved environmental quality. Natural forests, characterized by their rich biodiversity and complex structures, consistently display the highest RSEI values across various ecological zones, highlighting their pivotal role in maintaining ecological balance and delivering ecosystem services. In contrast, artificial forests, primarily situated at lower altitudes and often near human activities, show linear and stable temporal patterns with lower RSEI values.
Conclusion. Significant temporal fluctuations of RSEI were identified, particularly in the years 2002, 2010, and 2017, with a noticeable trend of decreasing fluctuation periods over time, likely reflecting the impact of recent forest conservation and restoration efforts. This study uniquely combines curve analysis with ecological indices to provide a comprehensive framework for understanding and predicting changes in forest ecosystems, offering crucial insights for future conservation and management strategies, especially in the Hexi Corridor.
64-81
Changes in the recurrence of dry thunderstorms under modern climate warming on the example of some regions of Yakutia and Krasnoyarsk Krai
Abstract
Introduction. The distinguishing characteristic of dry thunderstorms is the absence of precipitation accompanying these weather events, which contributes to the intensity and spread of wildfires induced by lightning strikes igniting combustible materials. In forested but unpopulated areas, dry thunderstorms are the main cause of fires. It is generally accepted that their recurrence increases with increasing aridity of the local climate. However, the features of changes in dry thunderstorm frequency in certain forest-rich regions of Russia under modern climate warming have not been sufficiently studied yet. Therefore, identification of these changes for regions located in Siberia is a topical issue of ecology and safety in emergency situations.
The aim of the work was to identify the trend in interannual variations in the recurrence of dry thunderstorm events during summer months and overall thunderstorm seasons for the period of 1961–2023 with regard to Yakutia and Krasnoyarsk Krai.
Objects and methods of research. The objects of the study were changes in dry thunderstorm frequency and mean monthly air temperatures in the surface layer of the atmosphere assessed during the months of the 1961–2023 thunderstorm seasons. The study was carried out using the correlation analysis method and Student's test.
Results. It was found that the trends of interannual changes in the recurrence of dry thunderstorms are determined not only by the local climate variations, but also by the geographical location of the studied areas. For the sites located on the Prilensky Plateau and in the basins of the Lena and Yana Rivers, during any of the summer months within the period under study, the climatic norms of dry thunderstorm recurrence increased much faster than those of recurrence of all thunderstorm events. This peculiarity was not observed in the areas located on the Oymyakonsky Plateau and the Middle Siberian Plateau.
Conclusion. The study showed that the synchronous correlation of variations in the recurrence of dry thunderstorms and the thermic regime of the territory is not significant for all locations, which indicates the presence of substantial influence of other factors, presumably landscape ones.
82-97
Даты. События. Комментарии
To the 95th anniversary of the outstanding forest scientist and educator Victor Ilyich Pchelin
98-103