Current issue: 58(5)
Articles containing the keyword 'puunkorjuu'
Category : Article
The area of stands studied by line plot survey was 594 ha. On the basis of the length of the inventory line the estimated proportion of harvesting strips was 14% and that of ditch openings 6% of the area. The calculated strip road spacing was 29 m. The option of the minimum diameter made it difficult to use the number of stems as criterion for thinning intensity. Thinning intensity evaluated according to the basal area had been stronger than recommended with low values of dominant height and milder with high values. The estimated removal according to stumps was 38 m3/ha on the average between the strips. The real removal has, however, been larger than that, as the strip road openings are made in connection with the first thinning.
The PDF includes an abstract in English.
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Rantonen,
E-mail:
hr@mm.unknown
- Päivänen, E-mail: jp@mm.unknown
Using literature and a simulator experiment, an ordinary processor and a grapple loader processor were compared in conditions corresponding to thinning later than the first commercial thinning. Visual bucking only was employed in the simulator experiment. The strip road spacing was 30 m and there was no preliminary skidding of the trees. The simulator experiment confirmed the view reached in the literature that work productivity of the grappler loader processor is 20–40 % greater than that of an ordinary processor provided that the stem size is under 0.2–0.4 m3.
The PDF includes a summary in English.
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Harstela,
E-mail:
ph@mm.unknown
- Maukkonen, E-mail: am@mm.unknown
Questionnaires were sent out to determine the volume of wood harvested from peatlands during 1978 and the harvesting problems encountered. In total there were 110 responses which accounted for 8 million m3 of wood harvested, of which 1.0 million m3 (14%) was harvested from peatlands. The largest proportion of wood harvested from peatlands was during the winter. Most of the respondents reportet that they wait for the soil frost to set before harvesting is started on peatlands. Respondents indicated a total of 263 machines bogging down in to the soil or, for 1978, a total for Finland of 750 to 1,000 machines.
The PDF includes a summary in English.
The PDF includes a summary in English.
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Saarilahti,
E-mail:
ms@mm.unknown
The aim of the study was to find out the effect of the working place meetings on the increased cooperation between workers and supervisors, the improved work performance, the intensified use of machines and the improved job satisfaction. In the study loggers, forest machine operators and forement were interviewed. The results showed that the working place meeting is a useful means to realise the above-mentioned aims.
The PDF includes a summary in English.
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Kyttälä,
E-mail:
tk@mm.unknown
In the first part of the study the hindrance of the remaining trees when felling trees by machines working from the strip road in selective thinning was studied on the basis of the literature. In the second part there was geometrically studied the need of schematic thinning in some type stands when bundles are pre-skidded straight-lined to the strip road. In average only 0-1 trees per pre-skidding trail needs to be removed. It was concluded that trees removed from the pre-skidding trail do not significantly increase the need of schematic thinning. Remaining trees do not limit the length of machine booms if the pre-skidding trails are planned during the felling.
The PDF includes a summary in English.
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Harstela,
E-mail:
ph@mm.unknown
The amounts of harvestable logging residues and stump and root wood were examined in the area where 100,000 solid m3 of stemwood was cut in 1975. The cutting amounts of stemwood from work sites suitable for harvesting of logging residues was 35,000 m3, and suitable for harvesting of stump and root wood 38,000 m3. The increase in the yield of wood (without bark) from logging residues compared with the unbarked stemwood was 2.4%. The same percentage of wood from stump and root wood was 5.0–5.8% depending on the harvesting loss.
The PDF includes a summary in Finnish.
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Mäkelä,
E-mail:
mm@mm.unknown
The article reviews the position of the Department of Forest Technology in Finnish Forest Research Institute, among Finnish establishments in research on forest work. In addition, it describes the current research programmes of the departments both in wood harvesting studies and studies on silvicultural work. The equitable aims of the former are to increase productivity, lower the cost level, ease the work and improve job satisfaction, as well as to improve the utilization of wood raw material. The latter aims at e.g. improvement of the biological results.
Future prospects are surveyed from the point of view of the goals imposed by the State on the research and, on other hand, the appropriations earmarked for forest work science. A regrettable conflict has arisen between them.
The PDF includes a summary in English.
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Hakkila,
E-mail:
ph@mm.unknown
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.
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Hannelius,
E-mail:
sh@mm.unknown
In this study a formula has been developed to describe the influence of the change of cost level on such a mechanization prognosis, where is assumed that wages and machine costs bear compound interest. In the study there are some numerical examples.
In the formula p1 = annual per cent increase of wages, p3 = annual per cent increase of machine costs, p2 = sudden and incident per cent increase of machine costs, and tv = delay in the profitability of mechanization.
The PDF includes a summary in English.
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Harstela,
E-mail:
ph@mm.unknown
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.
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Kärkkäinen,
E-mail:
mk@mm.unknown
The material of 78 damaged Norway spruce (Picea abies (L.) H. Karst.) trees was gathered in Southern Finland in order to clarify the advance of decay. The harvesting which had caused the scars had been carried out 12 years earlier and at the moment of the investigation the growing stand was 110 years old. It was noticed that the variables used could explain only a few per cent of the variation of the advance of decay. It was concluded that the only important thing in practice is whether the injuries are in roots or in stems.
The PDF includes a summary in English.
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Kärkkäinen,
E-mail:
mk@mm.unknown
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.
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Silvennoinen,
E-mail:
us@mm.unknown
- Haarlaa, E-mail: rh@mm.unknown
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.
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Kärkkäinen,
E-mail:
mk@mm.unknown
The most effective work organization will be used as a goal in minimizing of logging costs. Some type of problem approach is usually utilized. The concept of the ideal system offers a possibility to get guidance in this difficult task. The idea of an ideal system is based on the fact that an ideal system, even imagined, can be utilized for any purpose. There are checklists in handbooks to accomplish the four existing steps: define of function, design ideal, develop optimum and deliver results.
In this paper two special cases are taken up to illustrate the concept itself, and it’s use in design of forestry work organizations. There were found no such reasons which could limit or even prevent the use of this method for forest technological purposes. That is why the author believes the method to give better results than any other customary approach.
The PDF includes a summary in English.
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Haarlaa,
E-mail:
rh@mm.unknown
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.
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Kärkkäinen,
E-mail:
mk@mm.unknown
The purpose of this study was to answer questions concerning the basic information in planning of timber harvesting, how this information has to be handled, and how the planning of logging has to be combined with other forest management planning.
A deductive research method was used. By analysing a logging plan, prepared for a certain forest area, general conclusions were reached. To prepare the logging plan in connection with the forest management plan, the following information was found to be necessary: boundaries of the area, extent and ownership of the planned area, maps including information of the location of the timber and the conditions for transportation, road network and a reliable picture of the difficulty of the forest terrain.
Based on the material of the present timber harvesting methods it will be possible to predict the logging methods which will be applicable in the near future. The object to be planned has to be divided to operation areas. The amount of manpower and equipment needed can be estimated for each phase of the timber harvesting chain on the basis of the information calculated in this manner. Investments to machines and basic improvement works have to be planned before the effect of planning can be calculated in the logging costs, which are to be minimized. Due to the rapid development of the field, the handling of the material in connection with a forest management plan has to be left partly unfinished since the development of future logging methods cannot be reliably predicted.
The PDF includes a summary in English.
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Haarlaa,
E-mail:
rh@mm.unknown
In 1957 the annual cuttings in Finland were 40.2 million m3 without bark. The aim of the study was to estimate the rate of mechanization of harvesting of timber in Finland, and make a prediction of the state of mechanization by 1972. According to the study, harvesting and transportation of the felling volume in 1957 would have required about 25.5 million working hours. Mechanization of forest work has decreased it only by 0.32 million working hours. The profitability of forest work has improved in 1950s, which is mainly due to changes in harvesting, such as shifting to longer lengths of pulpwood and props and cutting unbarked timber.
The study predicts that in 1972 it will take 14.8 million working hours to harvest and 5.4 million working hours to transport a corresponding felling volume as in 1957. However, a new way of producing timber or a working method of wood may change the picture completely. Reduction in harvesting expenses through mechanization may lead to diminishing the minimum diameter of logs, which affects profitability of work. It is also probable that mechanization of wood transportation will lead to working sites with longer distances of forest transportation. Also, industry using wood as raw material will also obviously expand.
The article includes a summary in English.
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Putkisto,
E-mail:
kp@mm.unknown
Silva Fennica Issue 92 includes presentations held in 1956 in the 8th professional development courses, arranged for forest officers working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.
Fellings of valuable timber in the forests to be surrendered for settlement farms have been discussed widely in Finland. This presentation describes the effects of the new section in the Land Settlement Decree and new directions given by Central Forestry Association Tapio based on the decree. According to the directions, the fellings have to follow legislation concerning other fellings in private forests. The felling of all large, valuable timber, as has previously been the custom in settlement farm forests, does not follow this principle.
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Piepponen,
E-mail:
pp@mm.unknown
The wages of logging and haulage has been dependent on the decisions of foremen. The aim of this study was to provide better insight on how working conditions in a logging site affect productivity of the work. Six working sites operated by Forest Service, Veitsiluoto Oy and Kemi Oy in the communes of Salla, Muonio and Kolari in Lapland were studied. The forests in the area were mostly Scots pine (Pinus sylvestris L.).
The effect of average volume of the stems, the average daily haulage over distances of various lengths, density of the stand and shape of the stem on effectivity was calculated. The size of the team was of considerable importance to the felling and haulage result in the Northern Finland where the feller assists in loading of the logs. One of the aims of the study was to find out what size of team is most advantageous for each haulage distance. The results show the optimum distance of haulage for teams of different sizes.
The article includes a summary in English.
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Maliniemi,
E-mail:
em@mm.unknown
Category : Article
This is a fourth paper in a series of studies concerning logging in farm forests. The objective was to construct a model representing the productivity per farm of logging for delivery cuts. The first objective was to find out how the productivity of logging should be measured. In the study, combined labour and capital are regarded as the input.
Second object was to consider what variables to use in theory to determine the productivity of logging for delivery cuts. The factors affecting productivity depend on the concept of productivity employed. The productivity per farm of logging in delivery cuts can be determined both by regional and by farm variables. Still considering solely the effect of the quality of labour and capital input, the variables representing the person in charge of the delivery cuts are important explanatory farm variables. Others represent the farm totality (size, lines of production etc.).
Third aim was to develop a statistical-mathematical method suitable for constructing the model. Possible methods include regression analysis, which is, however, not the best method when there is large number of different levels to explain, or factor analysis. The suitable method to use in constructing a model depicting the productivity of a farm, was considered to be to condense the explanatory variables into rotated orthogonal factors. After preliminary correlation analysis, estimates of the factors interpreted as rational were employed as the explanatory variables for selective regression analysis.
Last, the model was tried out against actual material collected per farm, and the hypotheses were tested.
The PDF includes a summary in English.
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Mäkelä,
E-mail:
jm@mm.unknown
