Björheden Rolf, PhD.

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.

There are about 230,000 km of forest roads in Sweden, and maintenance and construction costs for forest roads per harvested cubic meter of wood is increasing. This is to some extent caused by increased demands for precision in delivery of fresh wood cut to customer specifications, shorter periods with frozen roads, increased vehicle weights and an ageing forest road network. Although many roads are constructed using the Swedish Forest Agency’s Guidelines, deviations are made to reduce construction costs. Further, short planning horizons reduces the period of settling, intended to allow the road to dry and consolidate under its own weight. In northern Sweden, central tyre inflation systems are used to reduce road wear from logging trucks and increase the period a road is accessible for traffic with logging trucks. To reduce road costs, the industry needs efficient road building methods and ways to reduce road wear. Thus, they want to know how thinner surface layers influence road wear and if reduced tyre pressures can help to reduce road wear on such roads. The aim of this study was to compare rutting by vehicles with low tyre pressures to rutting by vehicles running with standard highway tyre pressures on forest roads with thin surface layers.Three test roads, each divided into six sections with systematical sampling points for measurement of rut depth and road strength, were built. The test roads were trafficed by a fully laden CTI equipped log truck and trailer. Low tyre pressures were used on one side of the road and standard pressures on the other. Rutting was measured throughout the study. Reduced tyre pressures reduced rut development on two roads, while no differences could be found on the road that had not dried prior to testing. The positive effects of reduced pressures were largest on the best built road sections. The effect of thin aggregate layers should be further studied. This study failed in that sense as the variability in gravel thicknesses was to large within sections. Although the need to access the road may be high, access should not be approved until the terrace has dried and settled. Road wear can be mitigated by using CTI equipped trucks, but not on roads of too low quality.

There are about 230,000 km of forest roads in Sweden, and maintenance and construction costs for forest roads per harvested cubic meter of wood is increasing. This is to some extent caused by increased demands for precision in delivery of fresh wood cut to customer specifications, shorter periods with frozen roads, increased vehicle weights and an ageing forest road network. Although many roads are constructed using the Swedish Forest Agency’s Guidelines, deviations are made to reduce construction costs. Further, short planning horizons reduces the period of settling, intended to allow the road to dry and consolidate under its own weight. In northern Sweden, central tyre inflation systems are used to reduce road wear from logging trucks and increase the period a road is accessible for traffic with logging trucks. To reduce road costs, the industry needs efficient road building methods and ways to reduce road wear. Thus, they want to know how thinner surface layers influence road wear and if reduced tyre pressures can help to reduce road wear on such roads. The aim of this study was to compare rutting by vehicles with low tyre pressures to rutting by vehicles running with standard highway tyre pressures on forest roads with thin surface layers.Three test roads, each divided into six sections with systematical sampling points for measurement of rut depth and road strength, were built. The test roads were trafficed by a fully laden CTI equipped log truck and trailer. Low tyre pressures were used on one side of the road and standard pressures on the other. Rutting was measured throughout the study. Reduced tyre pressures reduced rut development on two roads, while no differences could be found on the road that had not dried prior to testing. The positive effects of reduced pressures were largest on the best built road sections. The effect of thin aggregate layers should be further studied. This study failed in that sense as the variability in gravel thicknesses was to large within sections. Although the need to access the road may be high, access should not be approved until the terrace has dried and settled. Road wear can be mitigated by using CTI equipped trucks, but not on roads of too low quality.