Том 20, № 4 (2023)

The study is aimed at testing and proposing some technological schemes for using mini-tractors as skidding mechanisms for cleaning cutting in forest. One of the advantages of this type of equipment on selective cuttings is the possibility to skid wood without cutting technological corridors in the forest. . Another advantage is the preservation of the ground vegetation and topsoil during the skidding of the harvested wood on the loading device. The MTR-1 mini-tractor created by students and staff of the Ural State Forestry University was used as a skidding mechanism. The article presents the results of three-year tests of an experimental mini-forwarder MTR-1 performance during severance cuttings in artificial and natural forests. Some technologies excluding cutting roads during logging operations have been tested. It is concluded that when choosing a scheme for the development of a cutting area it is necessary to take into account the configuration of the cutting area, its relief, the presence of glades, forest and dirt roads, and the trees location. It has been established that when the entire complex of cutting operations is performed by one person, the real productivity of a mini-tractor on wood skidding is 3.0—3.5 m3 per working day. It is recommended to use dunnage timber when skidding large logs to reduce the area of their contact with the surface. Remote control of the winch allowed the mini-tractor effective usage as a self-propelled winch at the initial stage of the cutting area development, to reduce the loading time of the logs and to increase the volume of harvested wood to 4 m3 per working day. In addition, this device allowed synchronizing the work of two people during operations that included short-length logging, skidding and stockpiling. Thus two people harvested 7.5 m3 per working day reducing the period of the cutting area development.

Snow as a road construction material is a combination of phases of the same nature but different aggregate states. Snow as a road surface is a complex spatial system that is topologically defined as a poli-relief, polizonal, multi-layered, and polydisperse medium. In natural conditions, the snow cover is subjected to different temperature conditions at different heights. The upper layers are influenced by continuously changing external air temperature, while the lower layers are in contact with the soil, which has a significantly higher and more stable temperature than that of the air. The temperature difference between the upper and lower layers leads to processes in the snow cover related to different elasticities of water vapors saturating the space above the snow grains. Water vapors move from the lower layers, which usually have higher temperatures and therefore higher maximum saturated vapor pressure, to the upper layers where the temperature and vapor pressure are lower. In order to determine the dependence of the thermal conductivity coefficient on density in the zone of high-density values, the authors conducted research on the thermal properties of snow of different densities. The research was conducted at Bauman Moscow State Technical University, as a continuation of previous studies [1]. The authors set two main objectives for the research: to identify the process of sublimation and evaporation in a snow mass located in a non-uniform temperature field, and to determine the quantitative aspect and intensity of this process depending on the density of the snow. The thermal conductivity coefficient of snow with different densities was also determined.

Clearing of cutting areas from felling residues is an important and necessary final logging operation. However, this work is considered unnecessarily costly by loggers and quite often is performed poorly, especially if the loggers are not engaged in future reforestation. No less often, forest officers pay special attention to the quality of this operation, and as a result fines to loggers for poor-quality clearing of cutting areas are common enough occurrence in a number of regions. This is due not only to the poor organization or quality of work on this operation, but also to the different interpretation of regulatory documentation requirements by foresters and forestry management. This review article justifies the possibility of “lean production” concept application to logging sites clearing operation that includes all stages of logging production: logging operations, forest transport, timber storage, and reforestation. Prospects for further effective use of felling residues, for example, as biofuel, are noted. The authors consider tasks and methods of felling residues collection and accumulation depending on the timber harvesting machines and operations, and machines and technologies for collecting felling residues.

The vast majority of wood in the Republic of Karelia is transported by logging trucks and about 85% of the transportation is performed on public roads. Being a heavy vehicle, a logging truck has a significant impact on the road condition. This impact is especially strong during the spring and autumn periods, when the roadbed soil is waterlogged and has lost part of its bearing capacity. During these periods the road surface is subjected to the greatest damage; its pattern requires studying to plan and organize timely repairs. The transportation network of public roads is an integral part of the logistics chains of the regional forest industry and its condition also significantly affects the efficiency of logging in general. The article considers the results of diagnostics of the highway network state in the Republic of Karelia for the presence and dimensions of defects. The authors analyzed the results of quantitative assessment of various destructions and the causes of their occurrence. Also they determined the length of roads in normative and non-normative condition.