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Silva Fennica 1926-1997
Acta Forestalia Fennica

Articles containing the keyword 'forest haulage'

Category: Article

article id 4921, category Article
Simo Hannelius. (1975). Ojitusalueiden kulkukelpoisuudesta puunkorjuussa. Silva Fennica vol. 9 no. 3 article id 4921.
English title: On the trafficability of drained peatlands in harvesting.
Original keywords: puunkuljetus; harvennushakkuu; puunkorjuu; turvemaat; ojitetut suot; metsäkoneet; puustovauriot; kantavuus; routa; koneistuminen
English keywords: soil frost; drained peatlands; thinnings; mechanization; forest haulage; timber harvesting; forwarders; bearing capacity; logging conditions
Abstract | View details | Full text in PDF | Author Info

During the next decade there will be a marked increase in the allowable cut in drained peatlands. At the same time, the mechanization in logging proceeds, and in short-distance haulage the use of forwarders will increase. This study, based on literature and some observations, deals with logging conditions in drained peatlands with special reference to the suitability of heavy logging machines for use in such terrain. In addition, soil frost and the bearing capacity of the frozen peat soil were studied.

Freezing of the soil in a drained peatland area depends prevailingly on the weather conditions during early winter. The factors influencing soil freezing of a drained peatland are completely different from those regulating the freezing of natural peat soils. The frost penetrates in general deeper in the drained than virgin peatland. The topmost peat layer does not, however, freeze uniformly. Generally speaking, the bearing capacity of a drained peat soil is lower than that of undrained peat due to lower water content.

It is concluded that heavy logging machines are probably not fitted for use in drained areas on peatland even if the average soil frost values recorded would suggest it. Moreover, because of their extremely superficial root systems, peatland forests are exposed to damages by heavy machines in thinning operations.

The PDF includes a summary in English.

  • Hannelius, E-mail: sh@mm.unknown (email)
article id 4883, category Article
Matti Kärkkäinen. (1973). Näkökohta kuitupuupölkkyjen siirtelymatkasta. Silva Fennica vol. 7 no. 3 article id 4883.
English title: A note on the moving distance of pulpwood bolts.
Original keywords: hakkuut; kuitupuu; metsätyö; puunkorjuu; metsäkuljetus; ajourat; kaato; kasaus
English keywords: forest haulage; pulpwood; timber harvesting; fellings; forest work; off-road haulage; strip road; bunching
Abstract | View details | Full text in PDF | Author Info

The aim of the paper was to analyse, using a computer simulation technique, the moving distance of pulpwood bolts when direct felling of trees is used and the bolts are gathered alongside the strip road. According to the results, the average moving distance of bolts depends in a complicated way on the usable part of the stem and the spacing of strip road. As a rule, the differences between moving distances of two-meter bolts weighted and unweighted by bolt volume of various trees is 0–16% when the strip road spacing is 30 m the reason being the fact that the heaviest butt bolts are often more far away from the strip road than the top bolts.

The PDF includes a summary in English.

  • Kärkkäinen, E-mail: mk@mm.unknown (email)
article id 4843, category Article
Unto Silvennoinen, Rihko Haarlaa. (1971). Metsätraktoreiden liikkuvuus lumessa. Silva Fennica vol. 5 no. 2 article id 4843.
English title: The mobility of logging tractors on snow.
Original keywords: puunkorjuu; metsäkuljetus; maastoluokitus; maasto; lumipeite; metsätraktorit; talvikorjuu
English keywords: snow; forest haulage; forwarder; timber harvesting; terrain; forest tractor; skidder; terrain classification
Abstract | View details | Full text in PDF | Author Info

The mobility of logging tractors was tested in the winter 1969 on difficult snow conditions to gather information for planning of logging operations and for logging machinery design. The tractors tested were Clark Ranger 666, Timberjack C, Valmet Terra, Ford Brunett 5000, Fiskars 510, BM-Volvo SM 660, BM Volvo SM 661, Ford Country 6, MF-Robur I and BM-Boxer T-350.

According to the results, there is a preference of tracked vehicles in difficult snow conditions compared to wheeled tractors. Ford Country with long and bearing full-tracks proved to have the best mobility. On downhill grades it was found significant differences between three-quarter-track-tractors and skidders, although the performance on level ground and uphill grades was relatively similar. The tracked vehicles can easier move on the packed snow layer and reach a higher speed.

The driving speed does not increase significantly until the density of snow has entirely changed through getting wet. Wet top layer of snow affects positively on driving, because it increases packing of the snow. Increasing density of the snow improves especially the mobility of broad-tired wheeled tractors. To be able to predict the driving speed of a tractor in winter working conditions one must know the depth of the snow layer and the density of the snow and the grade of the slope. In addition, the passages on the same route and the packing of the snow must be regarded.

The PDF includes a summary in English.

  • Silvennoinen, E-mail: us@mm.unknown (email)
  • Haarlaa, E-mail: rh@mm.unknown
article id 4830, category Article
Matti Kärkkäinen. (1970). Optimaalisesta vinssausmatkasta. Silva Fennica vol. 4 no. 4 article id 4830.
English title: The optimum winching distance.
Original keywords: puunkuljetus; harvennushakkuu; puunkorjuu; ajourat; vintturit; vinssausmatka; korjuukustannukset
English keywords: forest haulage; forwarders; terrain transportation; strip roads; winching distance; harvesting costs
Abstract | View details | Full text in PDF | Author Info

The goal of this study was to develop a mathematical model for determination of the optimal winching distance in different conditions as based on harvesting costs. In the thinned forest the strip roads are parallel and the winching routes perpendicularly to them. A directed felling of trees is used so that it is easy to make loads to be winched. The stems can also be prepared to timber assortments on the stump area and gathered to loads for skidding alongside the winching routes.

After winching the timber is transported using a forwarder mowing on the strip roads. If the stems have not been bucked in the forests, they are to be prepared to timber assortments before the following transportation, because the problem of turning whole stems in a thinned forest has not yet been solved.

In the mathematical model the formation of the costs was described using 18 variables of which 15 had an effect on the optimum winching distance. Some empirical values were estimated concerning these variables, and the corresponding optimum winching distance were computed. The optimum was mainly determined by the quantity of timber harvested per unit area, the size of the winching load, the regression coefficient of the times which were depended on the winching distance.

According to the model, the deviation from optimum winching distance does not cause a very great change in the analysed total costs. When the winching distance is longer, the increase of the costs is smaller than if it is shorter than optimum. In general, the increase of the costs was so small that in practice one obviously can be satisfied with rather approximate methods in determining the suitable winching distance.

The PDF includes a summary in English.

  • Kärkkäinen, E-mail: mk@mm.unknown (email)
article id 4819, category Article
Matti Kärkkäinen. (1970). Hakkuutähteiden merkityksestä puuston vaurioitumisen ja raiteenmuodostuksen kannalta harvennusmetsissä. Silva Fennica vol. 4 no. 2 article id 4819.
English title: Significance of logging waste in thinnings as to scars and tracks in the terrain.
Original keywords: maaperä; harvennushakkuu; puunkorjuu; metsäkuljetus; hakkuutähteet; metsäkoneet; maastovauriot; puustovauriot; ajourat; kantavuus
English keywords: thinnings; forest haulage; soil; timber harvesting; terrain transportation; strip roads; logging waste; tree injuries; stem injuries; tracks; carrying capacity
Abstract | View details | Full text in PDF | Author Info

The purpose of this study was to explain whether it is possible to affect, in practical working site conditions, by means of logging waste on the strip road, the depth of the track which is formed in terrain transportation and the injuries of the growing stand. Five 20 m long investigation areas with logging waste and five similar areas without logging waste were arranged on one strip road at Teisko logging site in Southern Finland. The logging waste layer was mainly Norway spruce and 10–15 cm thick. A KL–836 B forwarder was used. The type of soil was loam.

The logging waste affected the depth of the track only by decreasing the wear of humus layer. Even decreasing effect of logging waste on the injuries in the growing stand was minor. At Kitee working site in Eastern Finland strip roads were studied. The type of soil was thick, rather mouldered peat. The thickness of logging waste was 3–4 times greater than in Teisko, mainly spruce. A Volvo Nalle SM 460 forwarder was used. The effect of the logging waste on the depth of the tracks was clearly to be noticed. On basis of the appearance of the tracks one could assume that the difference was due to different wear of the humus, and not so much due to the quantity of logging waste that improves the carrying capacity of terrain.

In some extent logging waste was also found to affect the amount and quality of tree injuries. In practical working conditions, the importance might be small, since in the experiments an unrealistically great amount of logging waste was used.

The PDF includes a summary in English.

  • Kärkkäinen, E-mail: mk@mm.unknown (email)

Category: Article

article id 7089, category Article
A. Benj. Helander. (1923). Metsätalouden tarjoamasta ansiotyöstä. Silva Fennica vol. 26 no. 1 article id 7089.
English title: Employment in the forestry in Finland.
Original keywords: Metsähallitus; valtion metsät; metsätyö; työvoima; metsäkuljetus; hakkuutyö; hevosajo
English keywords: logging; forest haulage; employment; Forest Service; state forests; forest work; horse hauling
Abstract | View details | Full text in PDF | Author Info

Work in the forestry, for instance, in logging operation during winter, has been important source of employment for the rural population in Finland. The study is based on statistics of forest work, felling, felled timber, workforce and horses used in the forest work in the state forests, published in the annual reports of Metsähallitus (Forest Service) in 1911-1913. The administrative and silvicultural work, for instance, sowing and planting, clearing of the felling area, building forest roads or work in the nurseries, range from 20% to 22% of all work done in the forestry. Major part of the work time is used in felling. To harvest one cubic meter of timber requires 0.3 man-days and 0.2 horse-days. The work is seasonal; felling work is available for about 90-100 days a year. Forest haulage is possible only in the winter, and for instance sowing and planting in the summer. The employees have secondary jobs in agriculture and in other sectors.

The PDF includes a summary in German.

  • Helander, E-mail: ah@mm.unknown (email)
article id 7562, category Article
Rihko Haarlaa. (1973). The effect of terrain on the output in forest transportation of timber. Silva Fennica vol. 0 no. 128 article id 7562.
Keywords: forest haulage; timber transportation; terrain; forest tractor; transportation costs
Abstract | View details | Full text in PDF | Author Info

The first part of the study includes a summary of conclusions from five earlier reports dealing with terrain transportation costs, effect of terrain, load, snow and additional machine components on the mobility of forest tractors, and the distance a vehicle has to move in forest transportation of timber. In the second part of the study the effect of these separate factors on the transport output have been analysed on the basis of simulating a transportation of 3,000 loads by computer.

It was concluded that no specific terrain factor had a dominating effect on any component of the forwarding output. However, many terrain-factor combinations with a nonsignificant effect on the mobility and also on the forwarding output were identified. The most significant factors affecting the output were the size of load and the distance driven during the cycle.

The PDF includes a summary in Finnish.

  • Haarlaa, E-mail: rh@mm.unknown (email)
article id 7609, category Article
Matti Kärkkäinen. (1969). Metsän vaurioituminen kesäaikaisessa puunkorjuussa. Silva Fennica vol. 0 no. 100 article id 7609.
English title: The amount of injuries caused by timber transportation in the summer.
Keywords: logging; forest haulage; transportation; methods; logging damages; tree damage; terrain damage
Abstract | View details | Full text in PDF | Author Info

The purpose of this study was to build a mathematic predictive model for the formation of injuries and to try its usability in predicting. The empirical data consisted of 24 thinning sites, which were situated mainly in forests owned by forestry companies. The timber was made by strip roads. The terrain transportation of timber was carried out by forwarders or by agricultural tractor-trailer combinations.

The model has been compiled by multiple regression analysis. The predictive model has been interpreted so that the formation of injuries is, for one part, dependent of the number of trees exposed to damages, and, on the other hand, on the factors influencing the probability of injuries, the possibility for this existing. The number of trees exposed to injuries is dependent on the density of strip roads and on the amount of standing timber left after logging. The probability of injuries is influenced by the quality of the standing timber, the type of soil and the intensity of the timber harvesting process.

The predictive model has been interpreted in similar way as the number of injured trees. The possibility of formation of injuries is mainly affected by the length of strip roads and the amount of the standing timber. The probability of injuries is influenced, for the part of the number of root injuries by the strength of the soil type, and probably also by transportation equipment. For the amount of stem injuries no valid predictive equation was found in this study.

  • Kärkkäinen, E-mail: mk@mm.unknown (email)

Category: Research article

article id 1030, category Research article
Jussi Manner, Tomas Nordfjell, Ola Lindroos. (2013). Effects of the number of assortments and log concentration on time consumption for forwarding. Silva Fennica vol. 47 no. 4 article id 1030.
Keywords: productivity; time study; forest haulage; forwarders; cut-to-length logging; log extraction; terrain transport
Highlights: We analysed the effects of total and forwarded log concentrations (m3 (100 m)–1) and the number of loaded assortments on forwarding; The combination of the number of loaded assortments and their abundance (i.e. forwarded log concentration) affected time consumption most; This knowledge enables improved efficiency by optimizing number and assortment proportions in the various loads required to forward a stand.
Abstract | Full text in HTML | Full text in PDF | Author Info
Forwarding has been carried out for 50 years, but much is still unknown about this work. Its complexity comes from both stand features and essential decision-making. Forwarding time consumption is influenced by e.g. log concentrations and number of assortments. Traditionally, focus has been on the total log concentration (TLC), referring to all logs at the harvesting site. However, we focused on forwarded log concentration (FLC), the load-specific log concentration which depends on the assortment distribution at harvesting site and the load-specific number of assortments. To evaluate the effects of TLC, number of assortments in a load and FLC on the loading and unloading times, a standardized field experiment was carried out. Pile and load sizes were constant, while TLC and FLC were manipulated by varying the pile distribution on the test path. For all work elements, the time consumption per m3 was significantly affected by the number of assortments that were loaded, but only the “driving while loading” work element was also significantly influenced by TLC. However, when untangling the intercorrelation between tested factors, it was found that the time consumption for driving while loading significantly decreased as a function of FLC and was unaffected by the number of assortments in a load. That FLC influences the forwarding time consumption highlights the need to study the effects of combining various assortment proportions in a load. Such knowledge will enable analysis of the most efficient number and assortment proportions to combine in the various loads required to forward a given stand.
  • Manner, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden E-mail: (email)
  • Nordfjell, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden E-mail:
  • Lindroos, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden E-mail:
article id 346, category Research article
Tuomo Nurminen, Heikki Korpunen, Jori Uusitalo. (2006). Time consumption analysis of the mechanized cut-to-length harvesting system. Silva Fennica vol. 40 no. 2 article id 346.
Keywords: cutting; time study; forest haulage; single-grip harvester; forwarder; work phase
Abstract | View details | Full text in PDF | Author Info
The time consumption and productivity of harvesting are dependent on stand conditions, the operators’ skills, working techniques and the characteristics of the forestry machinery. Even if the basic methods and machine types of the cut-to-length harvesting system have not changed significantly in 10 to 15 years, improvements in the operators’ competence, technical solutions in forest machinery and changes in the working environment have undoubtedly taken place. In this study, the objective was to discover the special characteristics in the time consumption of mechanized cutting and forest haulage in Finnish conditions. The empirical time study was conducted with professional operators and medium-sized single-grip harvesters and forwarders in final fellings and thinnings in easy terrain in central Finland. The models for effective time consumption in the work phases and total productivity were formed. Stem size, tree species and bucking affected the cutting, whereas timber density on the strip road, the average driving distance, load capacity, wood assortment and the bunching result of the harvester operator had an effect on the forest haulage performance. The results may be used in simulations, cost calculations and education.
  • Nurminen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: (email)
  • Korpunen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail:
  • Uusitalo, Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 54, FI-39700 Parkano, Finland E-mail:

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