15 research outputs found
Learning Curves in Tree Section Hauling in Central Sweden
Payload development in truck hauling of tree sections was studied, using production statistics from central Sweden. An increase of payload weights over four years was observed.
Factors influencing productivity may be divided into groups connected to a) technology, b) human skills, c) work object properties and d) working conditions. Apart from varying weather and seasonal climactic change, no productivity change or development could be observed associated with technology, work object properties or working conditions during the course of the 49-month study. The operators studied were all experienced roundwood hauling contractors, but had no previous experience with tree section hauling. Their experience of the work studied and on the equipment increased during the study.
Under the stable conditions of this study, the most important factors influencing payload variation are increased operator skill and varying weather and climate. Meteorological data explained more than 70 per cent of the variation but a logarithmic increase of payloads along with a decreasing sensitivity to weather conditions remained unexplained. Hypothetically, this is accredited to growing operator skill including an increased ability to judge and compensate for varying characteristics of tree sections handled. If so, the learning phase might be longer than generally assumed. To shorten this low-productivity period is an important aim for vocational training for workers and contractors in forestry. Some methodological problems connected with the interpretation of production studies are also discussed
Raw Material Procurement in Sawmills' Business Level Strategy - A Contingency Perspective
The sawmilling industry is facing serious challenges; intensified competition, increasing substitution of wood for new materials and powerful customers posing extensive new demands.
Obstacles for a change towards a more competitive configuration of the sawmilling industry are context and contingency related. Corporate strategy building must be based on an analysis of such factors. A contingency analysis of the sector reveals an array of factors that underpin severe fragmentation. Thus, sawmills have limited possibilities to exert power within the sawn wood supply chain. To break free from the ties of sector fragmentation, business level strategy may be based on
- cost advantages based on scale, production technology and productivity, a competitive strategy traditional to the sawmilling industry.
- market domination through new/superior products and unique offers to customers. The development of new products, such as EWP, and closer co-operation with customers such as power retailers are examples of the second type of strategy.
- optimisation of raw material flows based on market information. Control and management of raw material flows is important for the sawmilling industry, as well as for other industries with similar production.
A sawmill with superior control of the inbound sawlogs will always have the upper hand on competition because it may produce and sell its products with high efficiency. In spite of their importance, these areas have received only limited attention. Controlled procurement, flexible management of forest operations and communication of short-term needs to the suppliers are vital issues for the purchasing sawmills, yet to be explored
Basic Time Concepts For International Comparisons of Time Study Reports
In this paper, a proposal for a system of basic time concepts is presented. The lack of uniformity of time concepts was identified by the group preparing this proposal as the single most important obstacle when trying to make international comparisons of time study reports. The aim of the proposal is to set standards for scientific presentations so that international comparisons and analyses of results are simplified. The proposal is not aimed at defining a terminology for practical time study, nor does it contain suggestions on what methods to use (or not to use). It simply contains a number of basic concepts for time measurement of work that should always serve as a basis for any study claiming international significance.
It is the suggestion of the 'terminology team' that study results should either be published using the terms defined by the proposal or in such a way that a transformation into the proposed concepts is possible
Development of Bioenergy from Forest Biomass – a Case Study of Sweden and Finland
The role of the forest sector in Finland and in Sweden is the starting point for a case study presenting motifs for forest bioenergy in the two countries. Forest bioenergy, evolving in symbiosis with the forest industry, has become important. The successful development builds on piggy-backing conventional forestry, rather than on parallel supply systems.
After thirty years, forest biomass has become the largest energy source in the two countries, contributing almost 1/5 of the energy needs. For developed countries, Sweden and Finland have leading positions in the use of forest fuel, and in related technologies and methods. However, progress has not been simple and drivers for the development have changed over time.
The 1970s »oil crises« put initial focus on energy security and on reducing the dependence on imported fuels. Later, other motifs have become fundamental. Sustainability aspects – especially mitigating climate change – have emerged as key arguments. Fuels from sustainably managed forests cause minor, if any, emissions of carbon dioxide.
The facts that wood-based fuels create rural jobs and improve the trade balance have been ancillary motifs, and the increased net sale of forest products that follows on fuel production will increase the cash flow of the forest owner. However, due to low compensation and high costs compared to the traditional forest products, from the forest owners’ perspective, the economic motifs for forest fuel harvesting are not decisive.
For economic use of biomass, heat sinks are important. Combined heat and power, e.g. for district heating plus electricity to the grid or for industrial process heat and power are profitable options. Further refinement is possible but its potential to increase profitability seems limited
Development of Bioenergy from Forest Biomass – a Case Study of Sweden and Finland
The role of the forest sector in Finland and in Sweden is the starting point for a case study presenting motifs for forest bioenergy in the two countries. Forest bioenergy, evolving in symbiosis with the forest industry, has become important. The successful development builds on piggy-backing conventional forestry, rather than on parallel supply systems.
After thirty years, forest biomass has become the largest energy source in the two countries, contributing almost 1/5 of the energy needs. For developed countries, Sweden and Finland have leading positions in the use of forest fuel, and in related technologies and methods. However, progress has not been simple and drivers for the development have changed over time.
The 1970s »oil crises« put initial focus on energy security and on reducing the dependence on imported fuels. Later, other motifs have become fundamental. Sustainability aspects – especially mitigating climate change – have emerged as key arguments. Fuels from sustainably managed forests cause minor, if any, emissions of carbon dioxide.
The facts that wood-based fuels create rural jobs and improve the trade balance have been ancillary motifs, and the increased net sale of forest products that follows on fuel production will increase the cash flow of the forest owner. However, due to low compensation and high costs compared to the traditional forest products, from the forest owners’ perspective, the economic motifs for forest fuel harvesting are not decisive.
For economic use of biomass, heat sinks are important. Combined heat and power, e.g. for district heating plus electricity to the grid or for industrial process heat and power are profitable options. Further refinement is possible but its potential to increase profitability seems limited
Multi-Criteria Decision Analysis (MCDA) in Forest Operations – an Introductional Review
Decision making in forestry is very complex and requires consideration of trade-offs among economic, environmental, and social criteria. Different multi-criteria decision analysis (MCDA) methods have been developed for structuring and exploring the decision-making process of such problems. Although MCDA methods are often used for forest management problems, they are rarely used for forest operation problems. This indicates that scholars and practitioners working with forest operations are either unaware of MCDA methods, or see no benefit in using these methods. Therefore, the prime objective of this review was to make MCDA methods more intelligible (compared with current level of understanding) to novice users within the field of forest operations. For that purpose, basic ideas as well as the strengths and limitations of selected MCDA methods are presented. The second objective was to review applications of MCDA methods in forest operations. The review showed that MCDA applications are suitable for forest operation problems on all three planning levels – strategic, tactical, and operational – but with least use on the operational level. This is attributed to: 1) limited availability of temporally relevant and correct data, 2) lack of time (execution of MCDA methods is time consuming), and 3) many operational planning problems are solved with regards to an economic criterion, with other criteria serving more as frames. However, with increased importance of environmental and social aspects, incorporating MCDA methods into the decision-making process on the operational planning horizon (e.g., by developing MCDAbased guidelines for forestry work) is essential
Changes in technical performance, mechanical availability and prices of machines used in forest operations in Sweden from 1985 to 2010
This study describes developments in large-scale logging technology in Sweden from 1985 to 2010. Data were collected from manufacturers' sales material and from large forest enterprises. On average, forwarders manufactured in 2010 had 27–33% higher boom lifting torque than those manufactured in 1985–1989. The inflation-adjusted prices of medium-sized single-grip harvesters remained the same, but prices of forwarders increased by 30–50% in this period. The mechanical availability of various classes of machinery used increased from 70–80% to 85–88% between 1985 and 2008. The harvesting costs of thinning decreased between 1990 and 1998, while those of final fellings decreased from 1985 to 2006. However, in 2008 costs of both thinning and final felling tended to increase. The productivity of logging by the Swedish forest enterprise SCA increased almost three-fold in the period 1985–2010. However, since 2003 there have been signs of declining productivity. Currently, there is considerable interest in harvesting forest biomass for energy production. The new work tasks involved will affect the configuration of forest machines. A possible trend is that a new generation of forest machines and methods will be developed to facilitate integrated handling of roundwood and forest biomass for energy generation