Current issue: 60(3)
Time studies and an ergonomic assessment were carried out in logging operations for three logging machines based on backhoe loader chassis. The time studies were completed with a follow-up study of one backhoe loader-based single-grip harvester. The studies indicated a productivity at the same level as that of specialized Nordic logging machines. Ergonomics also proved to be good. Mean ground pressure exerted by the backhoe loader-based logging machines was little higher than for some of the conventional Nordic single-grip harvesters to which it was compared. The ability of the machines to operate in the terrain was also good, even in rough terrain.
These machines can also be used for other jobs, such as ditch digging, road building and road maintenance. The machines then function more as carriers for attachments rather than custom-built backhoe loaders. By more careful planning of operations, the machines can be used to a higher degree and more effectively. The relatively low investment cost compared to many custom-built Nordic logging machines also contributes to a reduction of operating costs.
The influence of horizontal whole-body vibration of fairly low intensity alone and combined with the mental load and motor action typical for the forest machine drive on heart rate variability (HRV), respiration rate (RR) and heart rate (HR) was studied by testing five subjects. Horizontal vibration had an influence on HR, HRV and RR. ’Control activities’ had the most influence on RR and HRV, but some influence on HR, too. ’Moving the control devices’ (motor action) gave the same response in HR as ’control activities’, but not in HRV and RR. ’Control activities’ together with ’vibration’ had a more effect on HRV and RR than these two factors singly, but not on HR. The possibilities of using these variables in field studies are discussed.
The PDF includes a summary in Finnish.
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.
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.
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.
The share of occupational instruction at the Forest Machine School varies between 70 and 80%. The paper describes organization of the education, curriculum, teaching methods, practical training, machinery, and learning experience of the students. It discusses the influence of teaching programme, and school environment on attitudes and motivation of the students.
The school employs an adaptation of the TW I method in its actual methods of occupational instruction. The method of demonstration is also employed. The size of a training group has been restricted to 10 pupils, and the school has attempted to acquire plenty of instruction components, material for repair, and practice worksites. In this way the repetition of essentials can be guaranteed. The minimum factor in driver training is the competence to use a grab loader. In the training of mechanics the core competence is the diagnostics of defects and the making of adjustments.
The PDF includes a summary in English.
Harvester-mounted mobile laser scanning (HarvMLS) is a novel approach to quantify forest structure in situ during harvesting operations. However, its reliability relative to established aerial and ground-based laser scanning systems remains unknown. In this study, we benchmarked HarvMLS against drone-based laser scanning (DLS) and backpack mobile laser scanning (BpMLS) for forest structure assessment. Point cloud data were acquired using these laser scanning systems in a boreal forest in southern Finland during thinning operations in 2024. HarvMLS collected data during thinning, while BpMLS and DLS collected data immediately before and after thinning. A grid-level approach was used for point cloud processing. Sixty-two 10 m × 10 m plots were analyzed, each with pre- and post-thinning data. Forest structure was characterised using estimates of structural attributes and complexity. The structural attributes included canopy height, canopy cover (CC), and filled voxel proportion (FVP). Structural complexity was quantified using the coefficient of variation (CV) of the structural attributes. Furthermore, FVP was analyzed across various canopy height classes to evaluate the scanning system’s capacity to capture vegetation density at different canopy layers. The scanning systems consistently estimated canopy height, CC, and the CV of these attributes, including the CV of FVP. Significant differences were detected for FVP and FVP at lower canopy layers (<15 m). However, post hoc tests showed no significant difference between HarvMLS and BpMLS. These findings indicate that HarvMLS provides reliable estimates of forest structural attributes and their variability during active forest operations.
Highly mechanized timber harvesting and timber logistics emit CO2. In turn, the provided timber stores CO2 from the atmosphere as biogenic carbon. This basic assumption resulted in the calculation of net carbon storage of supplied timber. For this, we first developed a formula that represents the carbon content of freshly harvested timber. Coniferous wood contains about 734 kg CO2 m-3 and deciduous wood about 1000 CO2 m-3. Contrary to this, CO2 emissions from trucks, harvesters, and forwarders were calculated using the variable parameters for actual diesel consumption and the distance to the sawmill and constant parameters for the transport of the machine to the stand, lubricants, transport of operators, loading, and fabrication, supply, and maintenance. The method was tested on an actual harvest. The principal findings are that the method is practical, the net carbon storage of the supplied timber is reduced by 1.5% to 5% by harvesting and transport activities, and timber logistics is the largest contributor to emissions. The CO2 emissions for harvesters and forwarders are about 4 kg CO2 m-3, and for downstream timber logistics across all assortments and distances is 11 kg CO2 m-3. We conclude that the emissions are low, vis-a-vis the storage capacity. Emissions and a standardized calculation model are imperative. The model developed here for mapping the net carbon storage of roundwood highlights the climate protection performance of timber and contributes to optimizing climate-friendly timber supply chains.