Saint-Petersburg State Forestry University

Представлены данные по динамике поступления опада под полог ельника смешанного состава. Объект исследования – высокопродуктивный разновозрастный ельник кисличного типа леса. Для учета опада использовали квадратные опадоуловители размером 1 × 1 м в количестве 10 шт. Массу опада определяли один раз в месяц, исключая зимние месяцы. После сушки и взвешивания общая масса опада из каждого опадоуловителя разделялась на отдельные фракции, которые также взвешивались. Показано, что состав фракций опада изменяется по сезонам года существенным образом. Количество опада зависит от парцеллы – состава и структуры древесного яруса и других компонентов фитоценоза. Максимальное количество опада приходится на елово-кисличную и мертвопокровные парцеллы – около 54 % всего органического вещества. В опаде любого сезона преобладает хвоя ели, доля которой составляет более 77 % от общего объема. Размах варьирования доли хвои в составе опада небольшой – от 53 до 84 % в зависимости от сезона года. Мелкие сухие ветки привносят в годовой опад около 9 % с размахом варьирования по месяцам от 4 до 15 %. Выявлено два пика в сезонной динамике опада в данном ельнике – май и сентябрь-октябрь. Установлено, что более 65 % годовой массы опада приходится именно на эти три месяца. Полученные данные можно использовать для составления баланса органической массы и оценки запасов углерода любой лесной экосистемы с аналогичными характеристиками. The data on the dynamics of litter fall accumulation under the canopy of a mixed spruce forest are presented. The research object is a high-productivity, multi-aged spruce forest of the oxalis forest type. To account for the litter fall, 10 square litter fall catchers measuring 1 × 1 m were used. The mass of litter fall was determined once a month, excluding the winter months. After drying and weighing, the total mass of litter fall from each litter fall catcher was divided into separate fractions, which were also weighed. It has been shown that the composition of the litter fall fractions changes significantly throughout the year. The amount of litter fall depends on the parcel, which is determined by the composition and structure of the tree layer and other components of the phytocenosis. The maximum amount of litter fall is found in the spruce-oxalis and dead-cover parcels, accounting for approximately 54 % of the total organic matter. In the litter fall of any season, spruce needles predominate, accounting for more than 77 % of the total volume. The variation in the proportion of needles in the litter fall is relatively small, ranging from 53 % to 84 %, depending on the season. Small dry branches contribute approximately 9 % to the annual litter fall, with a variation of 4 to 15 % across different months. There are two peaks in the seasonal dynamics of litter fall in this spruce forest: in May and September-October. It has been established that more than 65 % of the annual litter fall mass falls on these three months. The data obtained can be used to calculate the organic mass balance and estimate the carbon reserves of any forest ecosystem with similar characteristics.

The review considers changes in ideas about the biosynthesis, structure, and functions of lignin in plants, starting from early references to the present day. Alternative viewpoints on the process of lignin biosynthesis, lignin spatial and supramolecular structure, and the nature of lignin-carbohydrate bonds were presented. A special place in the review belongs to the results of studies of lignin with the aim of reducing its content and changing the composition of the monomer units using genetic engineering methods. Comparison of the structures of the lignins isolated from transgenic and mutant trees and herbaceous plants showed that lignin biosynthesis is plastic and may involve, alongside canonical monolignols (coniferyl, sinapyl, and coumaryl alcohols), other phenolic compounds. Studies of so-called “stress lignins” demonstrated an important role played by lignin in plant protection against adverse environmental influences: mechanical damage, drought, low temperatures, pathogens, etc. The results of studies on gene modification of lignin allowed outlining a strategy of directed modification of the lignin biosynthesis process with the aim to obtain designer lignins, i.e., lignins with desired properties. This group includes so-called zip-lignins; they are characterized by the presence of ester linkages between the phenylpropane units. It is noted that, when conducting research into gene engineering of lignin, it is necessary to find a compromise between improving the processability of plant raw materials through lignin modification and the viability of transgenic plants.

Цель исследования: проанализировать конкурентоспособность уполномоченных экономических операторов (УЭО), ведущих деятельность в сфере таможенного дела путем выявления ключевых факторов, влияющих на их рентабельность, в условиях растущей рыночной конкуренции. Особое внимание уделено оценке применимости мультипликативной модели факторного анализа рентабельности активов, предложенной Bojana Vuković и соавторами, для анализа финансовых показателей УЭО. Методология исследования: в работе использован многофакторный линейный регрессионный анализ, основанный на данных бухгалтерской отчетности компаний за 2021-2023 годы, полученных из официального Ресурса БФО. Исследование включает оценку предсказательной способности модели Vuković для анализа рентабельности активов (ROA) и рентабельности собственного капитала (ROE) УЭО различных типов. Результаты исследования: установлено, что модель Vuković демонстрирует ограниченную применимость для анализа конкурентоспособности УЭО. Модель показала более высокую предсказательную способность для ROA по сравнению с ROE. Низкая эффективность модели может быть связана с её изначальной ориентацией на производственный сектор и ограниченной географией исходных данных. Оригинальность и значимость результатов: впервые проведена комплексная оценка применимости модели Vuković для анализа финансовых показателей УЭО в сфере таможенного дела. Результаты исследования подчеркивают необходимость адаптации существующих моделей к специфике таможенной деятельности и разработки новых, более точных инструментов для оценки конкурентоспособности и финансовой эффективности УЭО. Полученные данные имеют практическую значимость для совершенствования методологии анализа рентабельности компаний в сфере услуг. Research objective: to analyze the competitiveness of authorized economic operators (AEOs) operating in the field of customs by identifying key factors affecting their profitability in the context of increasing market competition. Special attention is given to assessing the applicability of the multiplicative factor analysis model of return on assets, proposed by Bojana Vuković and co-authors, for analyzing the financial performance of AEOs. Research methodology: the study employs multifactor linear regression analysis based on financial reporting data of companies for 2021-2023, obtained from the official BFO Resource. The research includes an evaluation of the predictive capability of Bojana Vuković's model for analyzing return on assets (ROA) and return on equity (ROE) of different types of AEOs. Research results: it was found that Bojana Vuković's model demonstrates limited applicability for analyzing the competitiveness of AEOs. The model showed higher predictive capability for ROA compared to ROE. The low effectiveness of the model may be attributed to its initial focus on the manufacturing sector and the limited geographical scope of the original data. Originality and significance of the results: for the first time, a comprehensive assessment of the applicability of Bojana Vuković's model for analyzing the financial performance of AEOs in the field of customs has been conducted. The results highlight the need to adapt existing models to the specifics of customs activities and to develop new, more accurate tools for assessing the competitiveness and financial efficiency of AEOs. The findings have practical significance for improving the methodology of profitability analysis for companies in the service sector.

This paper examines the use of fertilizers based on the sewage sludge in urban and forest park economy. The mentioned technologies allow achieving high agrochemical indicators and eliminating pathogenic microorganisms, which makes sewage sludge a valuable resource for increasing agricultural productivity and improving the condition of urban vegetation. The work is interesting for specialists in the field of agronomy, ecology and urban management.

The characteristics of maple syrup produced from Acer Trautvetteri Medw., growing on the northern macroslopes of the Caucasus, are presented in the article. The object of the study has been high-mountain maple stands at the lower limit of the vertical belt of their distribution. The geographical coordinates of the object are 42°56.352 N, 44°29.677 E. The altitude above sea level is 1374–1398 m. The slope steepness is 30–35°, the slope is exposed to the north. The beginning of sap secretion is the 3rd ten-day period of April, the duration of sap production is 12–17 days. The tapping has been carried out using a closed method. It has been shown that maple stand sap productivity averages about 4 t/ha per season. The main characteristics of maple sap and syrup have been determined by liquid chromatography in isocratic and gradient modes. The chemical composition of the syrup and the content of organic and inorganic components have been determined using a Maestro liquid chromatograph with spectrophotometric and refractometric detectors. The quantitative analysis of the elemental composition based on atomic absorption spectra has been carried out using a Contra AA 800 spectrometer with a flame and electrothermal atomizers. The sugar content in the sap has equaled 0.9–1.3 %. Maple sap syrup has been obtained by evaporation. The sugar content in the Trautvetter maple syrup has equaled 41 %, which is 12 % less than in the syrup produced in Canada. The proportion of glucose in the syrup is 1.7 %, the proportion of sucrose – 39.2 %. The content of Ca is 1286 mg/kg, the content of K – 9063 mg/kg. The elements such as Fe, Mn, Cu and Na in the syrup are present in small volumes – from 1 to 144 mg/kg. In terms of the content of identified chemical elements and organoleptic characteristics, syrup from the sap of the Trautvetter maple differs from syrup from the Canadian sugar maple. The data obtained contribute to solving the tasks of estimating the reserves of potential food resources of mountain forests in Russia. The results of the study can be used to update regulatory documents in the forestry sector and implemented into training programs for forestry specialists.