Articles containing the keyword 'tractor'

The objectives of this study were to record residual stand damage during harvesting operations and evaluate the influence of factors such as distance of the tree from the strip road, machine parts, operational phase, on the occurrence of tree wounds. The machine was a farm tractor equipped with a crane mounted on the front axle and a single grip harvester head. The study was carried out in two stands located in Southeast Sweden. Stand 1 was a 30-year-old Norway spruce (Picea abies (L.) H. Karst.) plantation on an afforested pasture while stand 2 was a 90-year-old mixed stand of Norway spruce, Scots pine (Pinus sylvestris L.), birch (Betula pendula Roth) and aspen (Populus tremula L.).

The mean damage percentage was 6.3% for the first stand and 6.5% for the second stand. Sixty-five percent of the wounds were less than 50 cm², with 91% of the damage occurring on the stem and 91% of the damage on or below the root collar. Sixty-six percent of the wounds produced by the stem under processing or by the harvesting head while only 10% of the wounds were produced by the tractor wheel. Damaged trees were distributed evenly in the crane reach zone. Significant differences were found between rut depths after one, two, four and six passes of the tractor in stand 1.

• Athanassiadis, E-mail: da@mm.unknown

The condition of forest road pavements was studied in spring, one week after maintenance and in autumn. The effect of vibrating blade was slightly better than that of pulled drag. Large loose stones couldn’t be pressed into pavement with either of the implements. The use of the vibrating blade was three times as expensive as the use of the pulled drag, however, the blade is suitable for other purposes as well.

The PDF includes an abstract in Finnish.

• Rummukainen, E-mail: ar@mm.unknown

The aim of this concise interview survey was to collect information about the servicing properties of forest tractors. Ten interviewees gave grades (in a scale from 4 to 10) concerning two servicing properties of various types of forest tractor. The rating covered the general safety during servicing (structural serviceability) and work postures during the work. Four types of forest tractor widely-used in Finland were chosen. The forwarders were of different size and structure.

According to the rating, the lightest forwarder was clearly superior to the other types. This machine was also the smallest in size and the most modern. Differences between the other three forwarders were not quite so clear. The variation between the machines as regards both so-called easy and troublesome tasks was considerable. Lubrication of the articulated shafts and supporting bearings was, however, very troublesome regardless the machine type. The heaviest tractor was considered the most difficult to service.

The PDF includes a summary in English.

• Rieppo, E-mail: kr@mm.unknown
• Väyrynen, E-mail: sv@mm.unknown

The areas of soil cultivation in regeneration sites using different methods in 1976–1979 and the cultivation units in use in Finland in 1979 were studied by means of a questionnaire. Application of soil cultivation methods appears to have become strongly polarized: in Southern Finland disc plowing with wheel tractors are used, whilst in Northern Finland wing plowing with crawler tractors is the most popular method, each being practically the only alternative in the respective area.

The PDF includes a summary in English.

• Kaila, E-mail: sk@mm.unknown
• Päivänen, E-mail: jp@mm.unknown

The paper deals mainly with the effects of jolting of forest tractors and processors on the health and working capacity of the driver. The literature surveyed presents especially the following points of interest: Jolting of the machine may hamper the focusing of the eyes and mastery of the controls. Long-term exposure to jolting may result in reduced sympathetic nervous activity at rest, and may impair an already existing back problem. Workers exposed to vibration, get more frequently gastric changes and changes in reproductive functions than usual. Jolting, as also the other negative physical factors of working environment, must be minimized as early as possible during the design of the machines.

The PDF includes a summary in English.

• Wuolijoki, E-mail: ew@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.

• Silvennoinen, E-mail: us@mm.unknown
• Haarlaa, E-mail: rh@mm.unknown

The changed in size and shape of ditches made by draining plows and tractor diggers were followed over a one-year period after the draining in four different peatland types. The material consists of 51 ditches made with each method in dwarf-shrub pine bog, herb-rich spruce swamp, in herb-rich sedge bog and sedge pine bog. The measurements were made immediately after the digging, and one month and a year later.

Ditches made by plowing and surrounded by peat became shallower quickly during the first 2–3 days after plowing due to the pressure of the surrounding peat. Ditches made with tractor diggers did not become shallower as fast, and their bottom did not widen to the same extent than plown ditched. During the first year, machine-made ditches change in a same way as handmade ditches, especially when compared to ditches made by tractor digger.

Immediately after digging the ditches made by tractor digger were 10 cm deeper and 0.13 m³ larger than plown ditches. One year later the values were 7,5 cm and 0.09 m³, respectively. Plown ditches made in the peat were 14.4 cm deeper than ditches that penetrated into the subsoil, for tractor digger the value was 13.2 cm. Ditches made with a tractor digger were deeper than plown ditches both in soils with deep and shallow peat layer.

The changes were largest and fastest in the wettest peatland type herb-rich sedge bog. In herb-rich spruce swamps, which have a shallow peat layer, the shallower plown ditches kept their form better than ditches dug by tractor digger.

The PDF includes a summary in English.

• Timonen, E-mail: et@mm.unknown

Forest transport of timber in Finland has been arranged as horse haulage during winter time using horses vacant from farm work. Tractors have now begun to replace horses in agriculture, which will lead to shortage of horses for timber harvesting in future. The aim of this investigation was to find a method of mechanized forest transport suitable for Finnish conditions. The method should be provided by an agricultural wheel tractor that is shared with agriculture. It should also be applicable to timber transport of relatively small forest holdings.

A method for time studies of tractor driven timber harvesting was developed. The competitivity of tractor transport of timber against the traditional method was studied in four pulpwood harvesting sites. The results suggest that if the tractor forest transport method in question is to be applied in practice, conditions should first be chosen which favour it most. A tractor forest transport method evolved on the basis of experiments presupposes certain conditions to be successful. These include snow for the construction of the packed-snow driveway, frost to harden the driveway, the location of strip roads in relatively easy topography, and of the main haulage road that is gently sloping in the haulage-loaded direction. The optimal transport distance for this method are about 3-10 km.

The PDF includes a summary in English.

• Putkisto, E-mail: kp@mm.unknown

The aim of the study was to search for differences in ergonomic effects between lateral 1, 2, 3 and 4 Hz whole-body vibrations of the forest tractor driver. Healthy male volunteers, both professional drivers and students, were exposed to 692 different vibrations in four different experiments, total number of subjects being 34.

Increase of vibration displacement affected clearly the subjects’ manipulating ability. The subjective magnitude rating of vibration correlated with energy content of vibration, but no correlation was found between subjective rating and heart rate, blood pressure or urinary catecholamine excretion, although the last variables mentioned indicate the energy consumption of the body. The professional drivers rated the vibration with smaller ratings than amateur drivers.

Frequency alteration of tractor vibration can be a possibility for reduction of vibrational effects as a tool for industrial hygiene.

The PDF includes a summary in Finnish.

• Wuolijoki, E-mail: ew@mm.unknown

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

In Finland The Central Forestry Board Tapio conducts forest drainage operations on swamps owned mainly by private individuals. This drainage is almost totally financed by the Government either as loans or subsidies. The local contractors have left bids about new forest drainage projects, and the best bid has won the contract. The trend of the average price for forest drains has been declining during the last 11 years although digging costs have increased. The aim of this study was (1) to explain the regional price variation of forest drains made by tractor-diggers and (2) to describe competition among tractor-digger contractors and to measure its effect on prices.

Correlation and regression analyses support the hypothesis that competition among tractor-digger contractors has decreased forest drain prices, especially in 1967. In the course of the last two years this competition effect has been lessening. The most significant other variables explaining price variations were the proportion of winter drainage, length of drainage work done for each participant in the project, and density of drains.

The PDF includes a summary in English.

• Palo, E-mail: mp@mm.unknown

Forest operations involve several different actors. Each actor imposes their own requirements on the harvester in relation to their differing roles in the industry, whether they are concerned with the harvester itself, information, environmental concerns, etc. The manufacturers of harvesters need to meet the requirements imposed by multiple actors, among them logging contractors, whose survival depends on their harvesters. This paper aims to identify the present drivers of product development and describe the roles of the actors who have been identified as those currently affecting the development of harvesters. A multiple-case study of harvester manufacturers was conducted. In total, 4 cases were studied. Each case was comprised of five interviewees: two from each harvesting manufacturer, two logging contractors, and one dealer. Following 20 interviews and 3 validation interviews (with experts from both the industry and academia), the paper concludes that the present drivers of product development of harvesters are legislators, logging contractors, and expert and research organizations. Harvester manufacturers appear to develop harvesters aligned with requirements coming from both logging contractors and legislators. Logging contractors are the primary customers, and they prioritize requirements that reduce cost and improve work environments. Legislators, and expert and research organizations are supporting development in relation to current regulations.

• Gustafsson, Department of Accounting and Logistics, Linnaeus University, Universitetsplatsen 1, 352 52 Växjö, Sweden E-mail: asa.gustafsson@lnu.se
• Johansson, Department of Forestry and Wood Technology, Linnaeus University, 391 82 Kalmar, Sweden E-mail: jimmy.johansson@lnu.se

Being a logging contractor involves several uncertainties, amongst others, information quality in the work order received from customers. The information quality of work orders is of the utmost importance for logging contactors, in order to be able to plan and conduct work properly. The purpose of this paper is three-fold: 1) identifying work order information components in harvesting, 2) identifying work order information quality dimensions in harvesting and 3) assessing work order information quality in harvesting. The paper is based on interviews and a survey. Various interviews took place in Sweden with professionals within the harvesting industry as well as logging contractors, and thereafter a survey was developed. Random selection was conducted and 100 Swedish logging contractors were contacted by telephone in order to answer the survey, with a response rate of 82% from the sample. The paper concludes that the information quality dimension of accuracy concerns the individual work order information components, whereas timeliness is related to receiving the complete work orders. A factor analysis has been conducted with five factors emerging. The assessment of work order information quality in harvesting implies that the potential for improvement exists with regard to increasing the accuracy of the order information for the components of “Cleaning under story trees – not conducted” and “Cleaning under story trees – of low standard” as well as “Landing – size”, and “Landing – placement”. However, their effect on capacity is utilization needs to be explored.

• Gustafsson, Linnaeus University, School of Business and Economics, Department of Management Accounting and Logistics, 391 82 Kalmar, Sweden E-mail: asa.gustafsson@lnu.se