Volume 21, Nº 1 (2024)
Articles
Experimental study of the forest machine mover impact on the reinforced composite base
Resumo
In recent years, large and medium-sized timber companies have begun to significantly equalize the volume of timber harvesting by season, switching almost to round-the-year harvesting and removal of wood, not counting the periods of road closures for drying. This is due to the need for uniform payments for the banking products they use, including for the purchase of forest machines, such as credit and leasing. At the same time, it is possible to objectively observe the results of global climate warming. For example, according to statistics, for the period from 1980 to 2020, i. e. for 40 years, the period of stable winter timber removal in the North-West of Russia has decreased by almost 3 weeks, and this is very significant. It is important to note that warming does not mean hot summers and warm winters. It may well be a cold summer with maximum precipitation and a frost-free, snow-free winter. The blurring of off-season periods is also becoming more and more characteristic. In other words, it can now be warm and damp almost all year round. The problem of rapid construction of a temporary road network in difficult conditions, with the help of collapsible coatings, has been learned to solve for a long time. However, the process of the forest machine mover impact on the reinforced composite base, which is a synthetic road mat and the underlying forest soil has not yet been studied. The article presents the methodology, equipment and results of experimental verification of a mathematical model of interaction of a wheel die-mover with a two-layer support surface, a model of a deformable plate placed on a pliable (Winkler) base.
1-25
Increasing the productivity of the felling-and-bunching machine LP-19 by improving the trajectory of the working tool
Resumo
Currently, there is a clear need for domestic logging equipment. The industry employs 1.5 thousand felling-and-bunching machines, including felling-and-bunching machine LP-19 and 3.5 thousands of other devices, both of domestic and imported origin. Most of the machines have been in operation for several decades and require replacement. The machine fleet is updated by about 3 percent per year, and the wear rate during logging operations exceeds 53 percent. This fact requires thorough work to develop import-substituting equipment. The paper presents a feasibility study of a developed integrated device usage for trajectory control of a handle, boom and working body of felling-and-bunching machine LP-19. Using the developed integrated device provides a relative reduction of verticality deviation of the working body with horizontal boom movement in the range from 150 to 160 % compared with the basic felling and bunching LP-19 machine configuration. It has been experimentally established that the use of the developed integrated control device provides a reduction in the time of the guidance operation of the working body (changing the boom outreach) from 13.2 s up to 7.7 s. The author has experimentally established that when using the developed integrated control device the average production time of 1 m3 of wood is less than that of the basic machine, which allowed increasing the productivity of felling and bunching LP-19 machine by 17%.
26-39
Design improvement of soil-tilling tools for forest side planting
Resumo
World forestry facing global environmental challenges aims at developing a modern model for utilization and regeneration of forests. Climatic change challenges require ecological potential rise of natural plantings by increasing the forest landscape area. Reforestation is a complex multi-operational process, one of the main stages of which is the broadcast or partial soil cultivation for a new forest plantation. This operation must be strictly a zonal one due to specific natural and industrial conditions. High survival rate of forest plantation and its further development largely depend on the quality of performed work. Modern technical means should be used to ensure high quality of soil cultivation. The authors present bottom and disc plows currently used for soil cultivation in forestry, PKL-70 plow being the most commonly used one. During operation the plow forms a single- or double moldboard furrow. If the seedlings are planted in the furrow bottom of water-logged soil, atmospheric and soil moisture accumulates and as a result plants damp off. Therefore in such conditions forest transplantation should be performed in specially created microhills, in particular in moldboards. Forestry experts note that in this case seedlings take root better and grow more actively. The authors consider modern forest plows designs used for cultivation of waterlogged soils with high plasticity are turfiness. They have developed additional units for refitting forest plows according to the modular-assembly principle. Their usage allows the quality and efficiency of soil preparation improvement by formation of flushed drained microhills for a new forest plantation. The modular-assembly principle may help reduce the range of machines and mechanisms used by forest owners.
40-52
Influence of tending felling on the growth and seed production of Siberian and Norway spruce trees in cultures in the Middle Urals
Resumo
The purpose of the research was to study the effect of tending felling on the regulation of stand morphostructure and density, trunk and crown growth, acceleration and increase of spruce reproductive ability. The object of the research was a site of 19-year-old Pícea obováta and Pícea ábies planted simultaneously on an old clear cutting in the spruce forest with the fresh moist soil covered with different grass species and green mosses. Tending felling was performed on the site with different thinning intensity of mixed forest stand. After clearing six sections were formed: one control section (without cutting), and five experimental ones with 19, 24, 38, 44 and 67 % tree trunks cut down. All the trees of natural regeneration were cut down on two last sections. It was found that the efficiency of tending felling resulted from the intensity of deciduous stand clearing. The maximum periodic (over 12 years) growth of the trunks height and diameter, projection and volume of crowns of both types of fir trees were noted in the last two sections. At the same time the complete absence of deciduous trees on the site contributed to the damage of the central shoots of the trunk and branches of spruce trees up to 5 m high by late spring frosts. Windfall spruce trees with the maximum crown size in the cultures of the third and early fourth decades were noted in the summer and autumn periods. The influence of these abiotic factors on spruce trees was not observed in sections with deciduous trees presence. By the age of 31 years Pícea ábies surpassed Pícea obováta by some taxation indicators. Clearing contributed to the active accumulation of spruce trees of both types in the first layer of the forest stand. Most of spruce trees grew on sections without deciduous trees and in rows thinned of fir trees. The increased size of fir trees crown and its constant solar illumination stimulated seed production due to larger number of reproductive organs compared to spruce trees on sections with the deciduous trees presence. Healthy spruce seeds in the traps were available every year in 15-year old stands. Their number (0.1—1.2 kg/ha) depended on trees age and the spruce cone harvest. Spruce undergrowth appeared between the rows of trees. Therefore is possible to form uneven spruce stands. The recommendations for the organization of a permanent seed plantation of Pícea ábies and Pícea obováta are given.
53-72
Quality control of spruce and pine logs for manufacturing high value added production
Resumo
The article reports the results of studies assessing the quality of spruce and pine logs harvested using cut-to-length technology (chainsaw-forwarder and harvester-forwarder), for further processing to obtain high value added production (souvenirs, musical instruments, and learning games for children). The manufacture of such products is one of the promising areas focused on advance wood processing. The wood must be ecologically clean and of high quality. Also any surface imperfections should be avoided at the stage of timber harvesting in the forest. Due to some Karelian logging enterprises appeals the research was performed to assess the quality of spruce and pine logs for further supply for manufacturing high value added production. The research was performed in the winter and summer seasons in the forest. The main defects of the logs, caused by the technology used were identified as well as their qualitative and quantitative level for summer and winter conditions. The research has shown that the common defects of logs in the technologies studied are mechanical damage (breakouts, raised grains of timber, saw damages) and processing defects (snags, splitting, splints, shakes). All these defects significantly reduce the quality of spruce and pine logs for further processing and lead to the loss of valuable material for manufacturing products with high added value. Thus, organizational and technological solutions have been proposed to reduce the culling level of log defects. The proposed solutions make it possible to achieve a positive effect from the rational use of raw materials in manufacturing wood products with increased added value. Harvester and forwarder operators must meet the regulations while maintaining the mechanisms of technological equipment, and the harvester head used must provide high forces and pulling speeds. Loggers and forest machine operators must be trained to assure the quality of timber.
73-85
Characteristic properties of spruce phytocenoses structure under conditions of intense anthropogenic impact
Resumo
The object of the study was spruce forests growing along the federal highway Murmansk — Saint Petersburg (960th kilometer of the highway) on different terrain elements. The inventory of the lower storey was performed on circular discount areas of 10 m2. At the same time, the height, age and condition of the understory and underwood, frequency and projective cover for all species in the composition of the living ground cover were recorded. Spruce forests in the roadside zone were experiencing intense anthropogenic impact due to a dense path network and traffic flows on the federal highway. The weak representation of individual forest components in these phytocenoses, poor species composition of vegetation in the living ground cover is shown. The stand featured a large number of dead trees (6—10 %) and windbreakage and windfall timber (8—15 %). The composition of the undergrowth was dominated by small specimens of spruce. The proportion of unviable undergrowth was more than 38 %, and the proportion of the dry one was about 10 % of the total amount of undergrowth. Single Quercus robur made about 100 specimens/ha. Other forest-forming species in the undergrowth were not identified. The undergrowth was represented by Sorbus aucuparia and Frangula alnus with a total number of about 3 thousand specimens/ha. The height of the main part of the undergrowth was 0.6 to 1.5 m. It was noted that the composition of the living ground cover was dominated by Vaccinium myrtilus, its frequency was 100 %, the projective cover was about 50 %. Green mosses covered most of the forest area with a projective cover of more than 50 %. Native species in the living ground cover were represented by a small number of Avenella flexuosa, Maianthemum bifolium and Vaccinium vitis-idaea. The light intensity mode under the canopy of the studied spruce forests varied with 4.32 thousand lux on the first experimental site and 5.34 thousand lux on the second one. This also resulted in the differences in the temperature regime of air and soil. The obtained materials may be used in assessing the state of forest phytocenoses experiencing intense external influence, as well as in the educational process.
86-99
Comparative analysis of foreign-made harvesters efficiency
Resumo
The paper presents an analysis of the efficiency of available harvesters, which is especially important in the current conditions of sanctions. The purpose of the study was to assess the effectiveness of foreign-made harvesters available under sanctions. The authors compared and analyzed the productivity of a harvester based on the SANY SY245F crawler excavator and the John Deere 1270G harvester; and assessed possible usage of a Chinese-made harvester based on the SANY SY245F crawler excavator in logging. The authors evaluated the work of a harvester based on SANY SY245F, with a harvester head WARATAH H480С and that of a harvester John Deere 1270G. The average output per man-day made 233.17 m3 for the John Deere 1270G (average hours worked per day 15.20 hours) and 207.67 m3 for the SANY SY245F-based harvester (average day hours worked 15.48 hours). On average, the output per man-day for a harvester based on SANY SY245F was 1.126 times less. As a criterion for evaluating the efficiency of logging machines, we used the coefficient of technological efficiency (СTE) adapted for harvesters. The analysis revealed a change in the values of the technological efficiency coefficient, while the maximum values of СTE = 0,638 and 0,647 were achieved at volume of stem 0,36 and 0.53 m3 and a net operating time of 7.5 and 9 hours, respectively (John Deere 1270G). A decrease in the values of СTE in other conditions allows us to state a decrease in the efficiency of the harvester under the influence of additional natural production factors, including unplanned operations. Evaluation of the harvester operation using the СTE criterion allows comparing the actual and theoretical efficiency of the logging machine, which in turn may allow identifying weaknesses and taking measures to increase equipment productivity and reduce costs. The analysis showed that harvesters made in China and, in particular, based on the SANY SY245F excavator are quite competitive in terms of efficiency with forest machines from other manufacturers.
100-112