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The extraction of timber is expensive, energy intensive, and potentially damaging to the forest soil. Machine development aims to mitigate risks for environmental impact and decrease energy consumption while maintaining or increasing cost efficiency. The development of rubber-tracked forwarders has gained renewed interest, not least due to climate change leading to unreliable weather in combination with low tolerance for soil damage. The increased cost of rubber tracks compared to wheels is believed to be compensated by higher driving speed enabled by semi-active suspension. Thus, the aim of this study was to theoretically investigate how the productivity and cost efficiency of rubber-tracked forwarders are affected by variations in driving speed and machine costs. The calculations were made with fixed stand parameters, to evaluate performance in well-defined working conditions, and with parameters from 2500 final felling stands in central Sweden, to evaluate performance in varied working conditions. Scenarios were compared to a baseline corresponding to mid-sized wheeled forwarders. The results show higher productivity with the increased driving speed enabled by rubber tracks and suspension at all extraction distances, with larger differences at long extraction distances. Assuming a 15% higher machine price for the rubber-tracked forwarder and a variable cost increase proportional to speed increase, extraction costs break even with the baseline at 400 m and 700 m extraction distance for moderate and fast driving speed, respectively. Furthermore, a rubber-tracked forwarder is likely to enable access to a larger part of the harvest area during longer seasons. For the studied set of stands, the year-round accessible volumes are estimated to increase from 9% to 92% with a rubber-tracked forwarder. With rubber tracks instead of wheels, good accessibility has the potential to be combined with low soil impact and cost efficiency in a favourable way for both industry and ecosystem. [ABSTRACT FROM AUTHOR]

There is a need to decrease the costs of cut-to-length operations. The harwarder, a one-machine system with the potential to reduce the costs, has been compared to the two-machine system (TMS) at the stand and regional levels but not at the national level, which is important as basis for decision to implement. The objective was therefore to analyze its potential on a large scale in Swedish final fellings. It was evaluated using two modeling approaches in conjunction with data representing around 30% of Sweden's yearly final fellings from five forestry organizations. The analyses revealed that total costs could be reduced by around 3% if up to 50% of the total volume was logged using harwarders rather than the TMS. This would require the introduction of up to 250 harwarders into machine fleets that currently use only the TMS. The two modeling approaches gave similar results. It was concluded that the harwarder may need to demonstrate greater potential to justify a full-scale implementation in Swedish forestry, but the machine could be improved through technological development, especially through automation. [ABSTRACT FROM AUTHOR]

There are many factors to consider when deciding which technologies to use in forest operations and how to plan their use. One important factor is the overall cost when choosing between the established two-machine system (TMS) with a harvester and a forwarder, and a one-machine system with a harwarder in final fellings. Such considerations can be done with different model approaches, all of which have their strengths and weaknesses. The aim of this study was to analyze and compare the TMS and harwarder potential using a Detailed Optimization (DO) approach and an Aggregated Heuristic (AH) approach. The main differences are the aggregation of seasons, including machine system teams, and spatial considerations. The analyses were done for one full year of final fellings for a large forest company's region in central Sweden, containing information necessary for calculating costs for logging, relocation between stands and traveling between the operator's home bases and the stands. The approaches were tested for two scenarios; when only TMS were available, and when both TMS and harwarders were available. The main results were that the approaches coincided well in both potential to decrease total costs when harwarders where available, and distribution of TMS and harwarders. There were some differences in the results, which can be explained by differences in thecalculation approach. It was concluded that the DO approach is more suitable when detailed analyses are prioritized, and the AH approach is more suitable when a more approximate analysis will suffice or the available resources for making the analysis are more limited. [ABSTRACT FROM AUTHOR]

In many parts of the world, contractors account for the main share of harvesting work. Harvesting is characterized by innate complexity and volatility, and this can affect contractors' workflow and ultimately their profitability. Thus, there is certainly a need for flexibility in harvesting service provision and procedures, but our current knowledge about contractors' workflow variations are limited. This study investigates workflow variations in harvesting services by comparing monthly variations between contractors' workload in terms of harvested volumes and the time spent on operations. The data originates from 77 machines belonging to contractors and their harvesting of 6.6 million m3 of roundwood in Sweden during a two-year period. The results indicate differences between contractors' workflow variations which can be attributed to the number of machines, machine sizes, and the workload in harvested volume and hours. These findings are relevant for guiding both the customer and contractor in this business relationship, and they could also serve as a basis for further research on the need for flexibility to effectively increase and decrease volume production in harvesting services. [ABSTRACT FROM AUTHOR]

The mechanization of roundwood harvesting in Sweden has historically cut costs rapidly. However, machinery and work methods have conceptually stayed the same since the introduction of the single-grip harvester. Current trends indicate that the next major wave of development will be based on automation, and that teleoperation is a step in this direction. This study aims to evaluate the economic potential of semi-automated tele-extraction compared to standard forwarding within the Nordic CTL two-machine harvesting system. The initial scenario examined autonomous terrain transportation with teleoperation during loading and unloading. A Discrete Event Simulation was implemented in the AnyLogic software. Input data included 1100 Swedish harvest sites, with in total 1.6 million m3 and extraction distances from 20 to 1500 m. Scenarios with different numbers of teleoperators for a fleet of ten forwarders were tested. The optimum number of operators was seven per ten forwarders, resulting in a potential extraction cost reduction of 7% compared to standard forwarding. Extraction distances further than 500 m enabled use of five or six teleoperators, resulting in potential cost reductions of up to 15%. The highest potential cost reductions were linked to increased time used for autonomous driving, increasing the teleoperator availability for other machines. The simulation model provides a framework for further evaluation of new scenarios of automation and teleoperation of forwarders. [ABSTRACT FROM AUTHOR]

The extensive outsourcing of forest harvesting operations means that the operational performance of contractors has an immense impact on the forest industry supply chain. This study describes perceived drivers and obstacles for strong performance in harvesting service based on semi-structured interviews with four production supervisors and eight contractors. The analysis of interview data revealed a wide array of factors considered to drive or hinder the performance. The factors were categorized into five types: Capability, Incentives, Commitment, Involvement and External factors. Factors concerning Capability, especially resources and competence, were most frequently considered by production supervisors as both drivers and hinders. The contractors considered most commonly Incentives to affect performance, especially motivation and strategy, as drivers and the economy as hinder. Both parties considered lack of resources as hinder to performance. For competence, relationship and collaboration interface, on the other hand, the two parties had different views on whether they acted as drivers or hinders. The knowledge presented in this paper is of interest to researchers or practitioners who wishes to understand the complexities underlying successful harvesting service performance. The insights can contribute to the reshaping of business practices to better target and leverage the mechanisms that most strongly affect performance. [ABSTRACT FROM AUTHOR]

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Even though stumpwood may become a significant part of the future fuel mix for combined heat and power plants in Sweden, the harvesting of stumps after regeneration felling is still only performed on a trial basis. Results from time studies on two, 23 tonne, excavators fitted for stump lifting, together with follow-up data on stump lifting and forwarding, are presented. Lifting, splitting, and piling the stumps accounted for 17, 32, and 32%, respectively, of the total productive work time. A predictive model was developed to estimate operational times and productivities when lifting pine and spruce stumps. Stump diameter, species, and terrain conditions contributed significantly to the fit of the model. The model predicts that productivity of stump lifting in spruce sites with easy terrain conditions and average stump diameters of 20 and 40 cm will be 1.23 and 4.19 oven-dry tonnes (ODT) per productive work hour, respectively. This is 43% higher than in pine sites with difficult terrain conditions and the same diameters. In the follow-up data, the productivity in stump lifting varied from 1.5 to 2.9 ODT per productive work hour while the cost for lifting and extraction to roadside varied from 37.8 to 59.4 €/ODT. [ABSTRACT FROM AUTHOR]

Abstract: Firewood is society’s oldest source of household energy and is still extensively used around the world. However, little is known about firewood usage in technologically advanced countries with high energy consumption. Some key issues include quantities of firewood currently used and future trends, as well as the influence of this usage on available biomass resources. This study addresses those issues through a postal questionnaire to 1500 of the firewood using households in a region in Northern Sweden. One-third of households produced 11–20 solid m3 of firewood per year. Three-fourths expected their production to be unchanged or increase during the coming five years. A large proportion of young producers indicated long-term continuation of firewood usage. Half (53%) of the firewood producing households owned forest and thereby had free access to wood. Produced firewood volume corresponded to 4–8% of the region’s roundwood volume harvested for industrial purposes. The use of firewood is suggested to influence decisions of private forest owners about management and harvest of forest biomass, and, thus, affect supply for bioenergy and other uses. With further incorporation of firewood usage into forest biomass management regimes, larger biomass quantities are likely to be available for industrial uses. [ABSTRACT FROM AUTHOR]

Abstract: Half of all Swedish forests are owned by private individuals, and at least 215,000 people work in these privately owned forest holdings. However, only lethal accidents are systematically monitored among self-employed forest workers. Therefore, data from the registries of the Swedish Work Environment Authority, the Labor Insurance Organization and the regional University Hospital in Umeå were gathered to allow us to perform a more in-depth assessment of the rate and types of accidents that occurred among private forest owners. We found large differences between the registries in the type and number of accidents that were reported. We encountered difficulties in defining “self-employed forest worker” and also in determining whether the accidents that did occur happened during work or leisure time. Consequently, the estimates for the accident rate that we obtained varied from 32 to ≥4300 injured persons per year in Sweden, depending on the registry that was consulted, the definition of the sample population that was used, and the accident severity definition that was employed. Nevertheless, the different registries gave a consistent picture of the types of accidents that occur while individuals are participating in self-employed forestry work. Severe accidents were relatively common, as self-employed forestry work fatalities constituted 7% of the total number of fatalities in the work authority registry. Falling trees were associated with many of these fatal accidents as well as with accidents that resulted in severe non-fatal injuries. Thus, unsafe work methods appeared more related to the occurrence of an accident than the equipment that was being used at the time of the accident (e.g., a chainsaw). Improvement of the workers’ skills should therefore be considered to be an important prevention measure that should be undertaken in this field. The challenges in improving the safety in these smallest of companies, which fall somewhere between the purview of occupational and consumer safety, are exemplified and discussed. [Copyright &y& Elsevier]

Abstract: Firewood is commonly used around the world, but little is known about the work involved in its production and associated accidents. The objectives were to identify relationships between accidents and time exposure, workers’ age and sex, equipment used and work activities in family forestry''s firewood production. Data from a postal survey in Northern Sweden were compared to a database of injuries in the same region. Most accidents occurred to 50–69 year old men, who also worked most hours. No significant differences in sex and age were found between expected and recorded accident frequencies when calculated from total work hours; however, when calculated using numbers of active persons significant differences were found for both age and sex. Frequency of accidents per unit worked time was higher for machine involving activities than for other activities. Accidents that occurred when using wedge splitter machines were responsible for most of this overrepresentation. Fingers were the most commonly injured body parts. Mean accident rate for the equipment used was 87 accidents per million work hours, and the rate was highest for wedge splitters (122 accidents per million work hours). Exposure to elevated risks due to violation of safety procedures is discussed, as well as possible preventative measures. [Copyright &y& Elsevier]