Logging Roads Research Articles

Особенности эксплуатации лесовозных дорог в весенне-зимний период

Seasonal roads are not capital construction objects. Unlike all-season ones, they can be of summer and winter action. During the transport development of forests, both allseason paved roads and temporary unpaved roads are required. The share of temporary roads is more than 90 % of all logging roads. One of the main problems of temporary logging roads is uneven seasonal operation, especially in summer. Seasonal roads do not have a permanent surface; more often it is natural soil, subject, except for mechanical impacts, to atmospheric ones, which is most evident in the summer-autumn period. Therefore, about 80 % of the harvested wood is exported via winter roads. The density of temporary roads depends on the general harvesting technology in a particular area, including the wood skidding distance and the angle of relative position of forest roads. Winter road construction works are carried out in summer and winter. In summer, engineering surveys are carried out, the optimal direction of the future route is determined, a clearing is cut, a roadbed is prepared, and if necessary, culverts are installed. With the onset of cold weather, the existing soil is compacted and leveled to accelerate its freezing. If the roadbed is sufficiently frozen, a snow-ice cover is formed. The article considers the influence of roadside forest plantations on the air temperature near the road surface, soil temperature, blocking solar radiation – the factors that are directly related to the overall service life of a winter road. Special attention is paid to slowing down the decrease in the winter road pavement strength in the shade of preserved trees by choosing the optimal route direction. The slowdown in the decrease in the pavement strength of the forest dirt road has been established and confirmed in areas where solar radiation is blocked by trees, i.e. in the shade. The difference in strength reduction to the minimum is 33 days. Based on the research results, it has been concluded that a comprehensive development of the logistics strategy for the organization of roundwood transportation via winter roads is necessary.

Оптимизация конструктивных параметров рекуперативного дышла лесовозного автопоезда

The main advantages and peculiarities of the interaction of the links of a logging road train when moving during wood hauling along under-equipped logging roads are considered. Based on the analysis of the results of the research carried out by Russian and foreign authors, promising ways to improve the efficiency of logging trucks with trailers have been identified. The main disadvantages of the existing designs of the devices for coupling logging trucks with trailers have been presented. An improved design of the regenerative pneumohydraulic rod of the coupler of a road train has been proposed, which ensures a reduction in the maximum efforts during the dynamic interaction of the links, an increase in the road train reliability, the possibility of the power fluid energy recovery with its subsequent beneficial use, as well as the effect of self-pulling of the road train, improving its cross-country ability in the conditions of under-equipped logging roads. It has been revealed that the optimal internal diameter of 2 double-acting hydraulic cylinders connected in series with the free ends is within the range of 95 to 105 mm. With such a diameter, the recovered power reaches 4 kW, the average longitudinal acceleration of the trailer is in the range of 0.75 to 0.83 m/s2. The movement of a logging road train in the studied conditions at a speed of 20 to 60 km/h is accompanied by a change in the average recovered power from 1.8 to 11.3 kW and the average longitudinal acceleration of the trailer – from 0.2 to 1.4 m/s2. It has been determined that at average heights of support surface irregularities of 0.1 to 0.2 m, characteristic of typical under-equipped logging roads, the average recovered power is in the range of 2.2 to 4.1 kW and the average longitudinal acceleration of the trailer is in the range of 0.26 to 0.53 m/s2. The optimal stroke of the regenerative pneumohydraulic rod of the coupler of a road train is 0.55 m, the optimal rate of lengthening (or shortening) of the rod is 0.28 m/s. This ensures the average self-pulling speed of 0.22 m/s, the mean displacement of a logging road train of 0.11 m per one cycle of lengthening (or shortening) of the rod and the power recovered by the rod of 1.75 kW.

Обоснование информационно-интеллектуальной поддержки принципов действия технических систем

Information and intelligent systems are a combination of knowledge, methods and technologies aimed at supporting specialists and engineers in the design, operation and optimization of technical systems. The task of searching for acceptable principles of operation of technical systems is achieved by searching for optimal solutions, analyzing their characteristics and identifying the most preferable options from the point of view of the assigned tasks. When searching for optimal solutions, various options for operating principles should be considered. A rational choice of the fundamental principles of the functioning of a technical system ensures the efficiency and quality of management decisions made. The purpose of this work is to substantiate the information-intellectual system of multivariate analysis, which provides the search for technical solutions. A logging road is considered as the object of study. The features of the organization of work during the construction of logging roads have been studied, and the choice of research method has been justified. An information-intellectual system is described that generates for further development acceptable principles of action in technical solutions in accordance with the formulated task. A description of the information-intelligent system for searching technical solutions is presented. The set of solutions is described in the form of an AND/OR tree, which allows you to efficiently store and select feasible solutions using graph methods.

Выбор критерия оптимальности при принятии управленческих решений в сложных технических системах

Criteria for the optimality of a management decision make it possible to predict possible options for solving a problem, analyze the influence of various factors and optimize the operation of the system. An effective management decision implies the choice of an option for solving a given problem that corresponds to the best achievement of the goal, in terms of initial information about the problem. Automating the search for multiple valid management decisions can significantly speed up the design process and provide more effective interaction between humans and systems. The use of a rational optimality criterion, taking into account the various stages of the system’s operation, will help to select optimal management decisions and achieve the goals of the project. Thus, the correct choice of optimality criterion ensures an effective search for solutions and helps to determine the set of optimal solutions for the designed technical system. This in turn allows you to increase the efficiency and quality of the organization. The purpose of this work is to substantiate the choice of optimality criterion for a management decision when designing a complex system - a logging highway. An analysis of existing criteria was carried out. An optimality criterion has been proposed and justified, denoting the effect of the construction of a logging road, calculated over the period from the beginning of its construction to the start of the first major repair. A system for automated search for management decisions is described.

Имитационное моделирование работы рекуперативного пневмогидравлического дышла сцепного устройства автопоезда с функцией самовытаскивания

Based on the conducted exploratory research, the most significant factors were identified on which the change in
 transport costs spent by logging enterprises on the process of delivering timber to consumers by logging trucks depends.
 To reduce such costs, a promising design of the drawbar of the coupling device of a timber road train has been proposed,
 providing the effect of self-pulling of the road train, generating and storing the energy of the working fluid, with its
 subsequent use in technological hydraulic equipment. To simulate the movement of a timber road train equipped with the
 proposed drawbar of the coupling device and the operation of the drawbar separately in the modes of self-pulling, recovery
 and damping of dynamic loads, two computer programs have been developed. It has been established that with an increase
 in the depth of irregularities, self-pulling of a timber road train becomes more difficult, which leads to a deterioration in
 the efficiency of the self-pulling process. However, with an average depth of unevenness of the supporting surface of less
 than 0.3 m, the efficiency indicators of the self-retracting process are acceptable values: the self-retracting speed is more
 than 0.22 m/s, the amount of displacement per extension-reduction cycle of the drawbar of the coupling device is less than 0.12 m, consumed by the pneumohydraulic drawbar of the coupling device power less than 1.9 kW. Under very
 difficult road conditions – the average depth of irregularities is from 0.3 to 0.5 m – the self-pulling of the timber road
 train occurs, but the efficiency indicators decrease: the self-pulling speed decreases to 0.16 m/s, the movement increases
 to 0.17 m, power consumption increases to 3.1 kW. It was revealed that when the coefficient of viscous friction of the
 wheels of a logging road train against the supporting surface of a logging road changes over a wide range, the recuperative
 pneumohydraulic drawbar of the coupling device provides a fairly effective self-pulling with a self-pulling speed from
 0.17 to 2.3 m/s, a displacement (rollback) value from 0.09 to 0.16 m, power consumption from 1.5 to 2.2 kW.

Analysis of methods for supporting management decision-making at designing the construction of logging roads

The construction of the logging roads network is one of the most costly items for logging enterprises. Improving the quality of management decisions, projects and their feasibility can be achieved through the use of the modern systems for designing and construction organization of the logging roads. An analysis of modern methods for making management decisions at organizing the construction of logging roads is carried out. Keywords logging roads, construction, design methods, management decisions

Study of the Strength Gain of Fiber Cement-modified Soil in the Logging Road Pavement

Study of the Strength Gain of Fiber Cement-modified Soil in the Logging Road Pavement

Обоснование перспективной схемы кривошипного гидромотора для гидропривода опорно-поворотного устройства манипулятора лесовозного автопоезда

The task of increasing the efficiency of hydraulic manipulators with traditional column turning mechanisms installed on logging road trains can be solved by installing column turning mechanisms with crank hydraulic motors from hydraulic cylinders. Variants of the arrangement of hydraulic cylinders in a crank hydraulic motor were studied graph analytically by determining tangential and radial forces acting on the rotary column of the hydraulic manipulator. At first, calculations were performed based on static methods to evaluate the effect of forces on the rods of hydraulic cylinders in the working positions of the column rotation mechanism. After that, using the COMPASS computer-aided design system, circular diagrams of tangential and radial forces of the considered options for the arrangement of hydraulic cylinders in a crank hydraulic motor were constructed. Further, in the Microsoft Excel program, graphs of changes in tangential forces acting on the rotary column of the hydraulic manipulator were plotted. Schemes with five and six hydraulic cylinders have the best option of influencing the bearings in which the column is rotated. The ranges of radial forces for them ranged, respectively, from 3.32 to 22.07 kN and from 11.175 to 11.297 kN, and tangential forces – from 257.893 to 285.274 kN, and from 300.471 to 354.059 kN, which can be used in the design of new drive designs for turning columns of hydraulic manipulators. For the practical implementation of the proposed design of the crank hydraulic motor, it is planned to make a rational choice of the location of the hydraulic cylinders of the crank hydraulic motor on the frame of the logging road train on the basis of simulation modeling.

Mobility, infrastructure and human environment relations in the Anthropocene

AbstractThis paper examines transport and mobility in rural and remote communities, focusing on trade‐offs between development and environmental protection in the Anthropocene. In Sarawak, a state of Malaysia, unpaved logging roads provide basic mobility for remote communities while contributing to the unsustainable and inequitable extraction of natural resources. I argue that the conditions under which transport infrastructure is provided prevent the possibility for sustainable development and pitch local people against a landscape that is the source of livelihoods and identities. The paper is interested in the life and agency of infrastructure and the environment, new materialism and critical approaches to development within human geography.

A Story about a South Fork Salmon River Logging Road and What It Means to Be a Good Ancestor

A Story about a South Fork Salmon River Logging Road and What It Means to Be a Good Ancestor

Use of logging roads by terrestrial mammals in a responsibly managed neotropical rainforest in Guyana

Selective logging is the most widespread use of tropical forests. Building logging roads facilitates access to previously remote rainforests, and so proper management is essential for ensuring biodiversity retention in logged landscapes. Terrestrial mammals often directly use logging roads (via movement corridors, hunting or foraging), making them vulnerable to poorly managed roads. Here we explore how the presence, arrangement and use of logging roads influence terrestrial mammal occupancy and detection within a Forest Stewardship Council (FSC) certified logged forest in Guyana. We compared camera trap data from20 natural ‘game’ trails in an unlogged area, with camera trap data from 23 sites set near to or on logging roads within the Iwokrama forest. Our findings showed high occupancy within logged areas with no statistically significant difference to unlogged areas. Higher detections were noted along secondary and feeder roads compared to skid trails and the natural trails in control areas. Additionally, our data showed a negative correlation between occupancy and distance to village for a scatter hoarding rodent, most likely driven by subsistence hunting by local communities. Our results indicate that proper road management geared towards the monitoring and guarded access of logging roads, can have a positive effect on terrestrial mammal occurrence within responsibly managed rainforests.

Использование армогрунта в конструкции устоев деревянного моста лесовозной автомобильной дороги

Wooden bridges have been used quite frequently on logging roads, regardless of their low durability and weak fire resistance. The preference is determined by the application of local materials in the construction and reparation, thus reducing the cost of the structure. However, the standard construction of the wooden bridge demands large amounts of conditioned draining bulk materials to support the cones, stone materials, or reinforced concrete slabs to protect against soil erosion. Besides, pile foundations are used on soft ground, involving heavy construction machinery. Reinforced soil foundations don’t have disadvantages of this kind. The application of innovative mounds for coastal support may reduce construction costs and increase operational capability. The purpose of the study is to estimate the potential of reinforced soil foundations in the construction of wooden bridge abutments. The results of the calculation for an abutment using reinforced support are presented. The calculations were performed for the standard loads A11, N11, and a forwarder. Additional research was performed to determine the parameters for the forwarder. According to the results, a mark of the forwarder with the maximum load on the abutment was identified. The maximum applied force was exerted by the load H11, and the minimum was A11. The stress from the timber truck Iveco-AMT 633920 (6×6) significantly exceeded the characteristic load A11, yet it was slightly lower compared to H11. The calculations for the abutment were done using the finite element method of the Plaxis 2D software. The parameters were limited to two groups of states. The calculations contained the external and internal stability factors along with the vertical and horizontal displacements of the reinforced structure. The external stability coefficient for the first loading scheme was 2.14; for the second loading scheme, it was 1.44. They exceed the permitted limit that is 1.375. In general, the results demonstrated that the reinforced soil abutment totally meets the requirements of the regulatory documents. For citation: Burgonutdinov A.M., Burmistrova O.N., Kleveko V.I., Litsinger Yu.K. Application of Reinforced Soil Foundations in the Construction of Wooden Bridge Abutments Along Logging Road. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 113–125. (In Russ.). https://doi.org/10.37482/0536-1036-2023-3-113-125

Оптимизация конструктивных параметров рекуперативного сцепного устройства, установленного в лесовозном автомобиле с прицепом

This article solves the problem of increasing the efficiency of the functioning of logging road trains in conditions of insufficiently equipped logging roads. Experience in the operation of road trains on such logging roads shows that on these roads the transport and operational qualities of logging road trains are low. The relevance of the scientific direction, aimed at achieving the fuel efficiency of logging road trains and thus increasing the efficiency and competitiveness of logging enterprises, is substantiated. An analysis of the work of foreign scientists is presented, which made it possible to identify significant factors that largely determine the efficiency of the process of hauling timber by timber road trains. A promising design of the coupling device is proposed, which allows converting and usefully using the kinetic energy of the mass of the trailer with timber, which occurs during the movement of a road train along insufficiently equipped logging roads in unsteady and transient traffic modes. The study was based on mathematical and simulation modeling, numerical methods, as well as modern methods for obtaining and processing information with computer support. A mathematical model and a computer program for the movement of a timber road train under changing road conditions have been developed. Computer simulation made it possible to carry out a preliminary assessment of the performance of the proposed pneumohydraulic coupling device with recuperative and damper mechanisms by identifying and analyzing dependencies characterizing the change in the studied performance indicators on the driving conditions of the road train and the design parameters of the device. It has been established that the coupling device during the movement of a logging road train in difficult road conditions at a speed of 30 km/h makes it possible to recuperate up to 7 kW, while the value of the longitudinal acceleration of the trailer link relative to the logging vehicle does not exceed 0.83 m/s2. It is determined that the value of the optimal diameter of the recuperative hydraulic cylinder is 80 ... 100 mm, and the optimal piston stroke is 83 ... 100 mm. In this case, the average power recuperated by the device will be at least 7 kW, and the average longitudinal acceleration of the trailer will be no more than 0.8 m/s2. It was found that the developed recuperation system remains effective in a wide range of roughness heights of 0.2 ... 0.4 m, providing a recuperated power of 2.3 ... 19.7 kW, respectively, with an acceptable average longitudinal acceleration of 0.3 ... 2.2 m/s2. The results obtained will be used as recommendations for designers to refine the proposed coupling device at the design stage.

Анализ современных методов изыскания лесовозных автомобильных дорог

Рассматриваются методы изыскания лесовозных автомобильных дорог в пространстве и обоснование выбора наиболее эффективного для конкретных условий метода. Современные автомобильные дороги в общем и лесовозные в частности характеризуются комплексом инженерных сооружений, где наиболее ответственными являются криволинейные участки, во многом определяющие уровень технико-экономических показателей и безопасности движения транспорта. Наиболее сложными из этих сооружений являются развязки в разных уровнях. Разбивке подлежат, в числе прочих элементов транспортных развязок, петлеообразные и прямые левоповоротные съезды, характеризующиеся сложным сочетанием горизонтальных и вертикальных кривых. В качестве вертикальной кривой чаще всего здесь применяется квадратная парабола, горизонтальными кривыми являются круговые кривые, клотоиды, биклотоиды, лемнисканты и наиболее отвечающие реальным условиям движения на лесоповоротных съездах тормозные кривые. Последние служат для смягчения влияния центробежой силы на автомобиль, двигающийся с плавным замедлением, переходя с прямолинейного участка на кривую, или с ускорением, выезжая на прямую. Тормозные кривые применяются в практике дорожного строительства. Несмотря на это, они еще недостаточно изучены и описаны в специальной литературе. Расчетные формулы для проектирования и разбивки тормозных переходных кривых требуют существенного изменения и дополнения с целью более плавноговписывания автомобиля в кривую и повышения безопасности движения. Представляют интерес плоские пространственные закругления, являющиеся воплощением прогрессивной взаимосогласованности плана и профиля дорожной трассы, благоприятно влияющие на условия видимости и общее зрительное восприятие дороги. Эти участки образованы соединением горизонтальной и вертикальной кривых в единую плоско-пространственную кривую. Разбивка таких закруглений непроизводительно делится на вертикальную и горизонтальную. Очевидно, что новая прогрессивная методика проектирования требует новых, более совершенных методов разбивочных работ. The paper discusses the methods for finding logging roads in space and the rationale for choosing the most effective method for specific conditions. Modern highways in general and logging roads in particular are characterized by a complex of engineering structures, where the most important are curved sections, which largely determine the level of technical and economic indicators and traffic safety. The most complex of these structures are interchanges at different levels. Among other elements of transport interchanges, loop-like and straight left-turn ramps, characterized by a complex combination of horizontal and vertical curves, are subject to breakdown. As a vertical curve, a square parabola is most often used here, horizontal curves are circular curves, clothoids, biclotoids, lemniscants, and braking curves that best meet the real conditions of movement at forest turning ramps. Braking curves serve to mitigate the effect of centrifugal force on a car moving with a smooth deceleration, moving from a straight section to a curve, or with acceleration, leaving a straight line. Braking curves are used in the practice of road construction. Despite this, they are not yet sufficiently studied and described in the specialized literature. Calculation formulas for designing and splitting brake transient curves require significant changes and additions in order to more smoothly fit the car into the curve and improve traffic safety. Of interest are flat spatial roundings, which are the embodiment of a progressive mutual consistency of the plan and profile of the road route, favorably affecting the visibility conditions and the overall visual perception of the road. These sections are formed by connecting the horizontal and vertical curves into a single plane-spatial curve. The breakdown of such roundings is unproductively divided into vertical and horizontal. It is obvious that the new progressive design methodology requires new, more advanced methods of layout work.

Ethnobiology Study: Game in Dayak Lun Dayeh Community at Watershed of Mentarang in Malinau

Dayak Lun Dayeh is a local community who lives in East Kalimantan, where they have practiced hunting both in traditional and modern ways. They have particular ways to find hunting spots and use hunting techniques. The research about this community was conducted in watershed of Mentarang, in order to determine the various kinds of games, frequently used hunting locations, and hunting ways of Dayak Lun Dayeh community. This study was carried out at two different times, on May–July 2016 and June–August 2021. Research data were collected through open-ended interviews (assisted by a key informant), field observation and photographic record. Data were presented descriptively by an ethnobiology approach. The results showed that this community practices subsistence hunting of games, which comprised mammals (69.73%), reptiles (14.15%), aves (8%), and amphibians (0.4%). The bush meat obtained from hunting was consumed as a protein source and served as a medium in traditional ceremonies or religious rituals based on ancestral teachings. Games such as Cervus unicolor, Sus barbatus, Muntiacus atherodes could be found easily at abpa' nuvan (salt-lick) rather than at primary forest, swidden (latii), swidden fallow (including amug, jekau and ripa), farm, river, or secondary forest such as the logging roads of former timber companies. Several hunting techniques were applied such as using hunting dogs for tracking the games (gelibut), sieging or waiting (gabang) at a specific location (abpa' nuvan), and setting traps (ton).

Even minor logging road development can decrease the functional diversity of forest bird communities: Evidence from a biodiversity hotspot

Although the effects of major roads and highways on biodiversity have received considerable attention, there is a lack of research considering how smaller and less-used roads might also impact wildlife, especially during the initial re-used development phase of abandoned roads, despite these minor roads being much more extensive and pervasive. Here, we examined how even minor redevelopment of former-abandoned logging roads can impact bird community alpha and beta diversity indices at the taxonomic, functional, and phylogenetic levels in a biodiversity conservation hotspot in central China. The minor redevelopment (i.e., re-paved) of former-abandoned roads generally reduced bird alpha and beta diversity compared to undeveloped abandoned roads, especially at the functional level. Compared with continuous-use roads, minor road redevelopment shows only a slight impact on avian diversity. Notably, compared to old-growth forest reference stands and undeveloped abandoned roads, minor road redevelopments have negative effects on the recovery process of avian diversity. Furthermore, the structure and composition of the high tree layer significantly affected avian functional and phylogenetic diversity, and low shrub layer vegetation mainly influenced taxonomic and phylogenetic diversity. To mitigate the effects of minor forest logging roads on avian biodiversity in priority biodiversity conservation areas, we propose the following: (1) roads that have fallen into disuse should be allowed and encouraged to re-naturalise; (2) roads should only be paved, and cleared back as strictly necessary, allowing grassy or gravel roads to suffice where possible; and (3) if road development is necessary, key umbrella tree species should be planted deliberately to support maximal community diversity and to maintain ecosystem functions and processes.

Review: Religion and Culture in Native America, by Suzanne Crawford O’Brien with Inés Talamantez

Review: <i>Religion and Culture in Native America</i>, by Suzanne Crawford O’Brien with Inés Talamantez

Is the Current Forest Management to the Northernmost Population of Cordulegaster heros (Anisoptera: Cordulegastridae) in Central Europe (Czech Republic) Threatening?

Cordulegaster heros is included in the EN category on the IUCN Red List for the territory of the Czech Republic, where it inhabits an area of approximately 100 km2. All of the localities are located in the forest complex in Chřiby hills, and all of the forests fall into the category of management forests. Most of the forest stands have a high and very high degree of naturalness; they are natural forest stands. The predominant management units are Nutrient sites in middle elevations (78.2% of the area) and Oligotrophic sites in middle elevations (2.1% of the area), with stand types of Fagus sylvatica representing 92.5% of the area, and forest stand types of Quercus sp. representing 5.7% of the area. The wider alluvia in forest streams are classified as being in management unit alder and ash sites on waterlogged and floodplain soils (1.1%), with the forest stand type of Alnus glutinosa. The forest stands are restored by regeneration under shelterwood (97.8% of the area). The waterlogged alluvia, if a separate management unit is established for them, are restored by a regeneration by strip method. Realistically, seven factors were recorded in C. heros habitats, but they mostly have only point effects. Within forestry management, the factors of logging directly in the habitats and the subsequent transport of harvested timber in the habitat were recorded. The most intrusive effects were found on tractor logging roads, where fine soil washes into the stream and causes prolonged turbidity. Of the water management structures in the study area, logging roads with bridges and culverts are constructed, stream banks are reinforced with longitudinal walls at points, and stone steps in the channels are constructed only sporadically. The current forest management system can be described as a nature-friendly system, and therefore, it fully ensures the conditions for the survival of the C. heros population in the Czech Republic.

ВЛИЯНИЕ РЕЖИМОВ ДВИЖЕНИЯ ЛЕСОВОЗНОГО АВТОПОЕЗДА ПРИ ВЫВОЗКЕ ЛЕСОМАТЕРИАЛОВ НА ЭФФЕКТИВНОСТЬ РЕКУПЕРАЦИИ ЭНЕРГИИ В ПНЕВМОГИДРАВЛИЧЕСКОМ СЕДЕЛЬНО-СЦЕПНОМ УСТРОЙСТВЕ

The necessity of increasing the efficiency of logging road trains by reducing the transport costs spent on hauling timber in existing road and climatic conditions is substantiated. A review of scientific research by foreign scientists is presented, which made it possible to identify the most significant factors influencing transportation costs. A promising design of a recuperative pneumohydraulic fifth wheel coupling device has been proposed, which makes it possible to reduce transportation costs by reducing the amount of fuel used by a road train, to increase the reliability of a logging road train by reducing the dynamic loads that occur between its links when driving over uneven surfaces of a logging road. The mathematical model of the movement of a timber tractor with a semi-trailer equipped with the proposed coupling device, under conditions of frequent accelerations and decelerations, over the unevenness of the logging road has been improved, which makes it possible to perform a preliminary assessment of the energy recovery by the proposed device in various modes of transient processes, as well as to investigate the influence of the main parameters of the recuperative pneumohydraulic fifth wheel coupling device for performance indicators. Two computer programs have been developed to study the performance indicators of a recuperative pneumohydraulic fifth wheel coupling under various transient modes of movement of a logging road train with given parameters of roughness of a logging road. It has been established that the use of the proposed coupling device in a logging road train makes it possible, when driving with randomly repeated decelerations and accelerations, to regenerate power up to 6.5 kW, and also to achieve a value of longitudinal acceleration of the semi-trailer relative to the tractor of 0.72 m/s2. Computer modeling made it possible to establish the value of the optimal diameter of the hydraulic cylinder, which provides the highest value of recuperated power at the lowest value of the acceleration of the semi-trailer relative to the tractor.

Variation in adult and pup wolf diets at natal den sites is influenced by forest composition and configuration.

Although wolves are wide-ranging generalist carnivores throughout their life cycle, during the pup-rearing season wolf activity is focused on natal den sites where pup survival depends upon pack members provisioning food. Because prey availability is influenced by habitat quality within the home range, we investigated the relative importance of prey species for adults and pups and further examined the relationship between habitat characteristics, wolf diet, and litter size on Prince of Wales Island (POW) in Southeast Alaska. During 2012-2020, we detected 13 active den sites within the home ranges of nine wolf packs. We estimated minimum pup counts using motion-detecting cameras and individual genotypes from noninvasive samples (hair: n=322; scat: n=227) and quantified wolf diet composition using fecal DNA metabarcoding (n=538). We assessed habitat composition, configuration, and connectivity within denning and annual home ranges estimated using wolf GPS-collar data. Contrary to expectations, wolves had a more constricted diet during denning season (April 15-July 31), and within this season pups had a narrower dietary niche (species richness [S]=4) focused more on deer (relative frequency of occurrence [O/I]=0.924) than adults (S=15; deer O/I=0.591). Litter size had a positive relationship with the relative frequency of deer in a wolf pack's diet. Wolf consumption of deer was positively associated with the proportion of young-growth forest (≤25 years old) within denning and annual home ranges. High levels of vegetation patch interspersion, and the density of closed logging roads were also important predictors, suggesting these habitat qualities were influential for increasing the availability of deer to wolves. Our results contrast with previous research indicating wolf pup diets included more alternate prey (i.e., beaver) than adults and emphasize the importance of deer to wolf viability on POW, especially during denning season.