Volume 14, numéro 2, july 2003

EN :

Forwarder fuel consumption was studied by examining a total of 27 forwarders under field conditions. Three datasets, representing different data acquisition methods, were used. In a field study, time and fuel consumption by work-element of two 20-21 tonne forwarders in final felling were recorded. In a questionnaire survey, daily data concerning fuel consumption, productivity and average extraction distance was provided on 18 forwarders, divided between final felling and thinning. Finally, accounting data on fuel consumption for 11 forwarders were obtained.

In the field study, the fuel consumption varied between 8.3 to 15.7 l/PMH (productive machine hour) for different work elements. The total fuel consumption was 0.28-0.36 l/m3sub (solid under bark) at average extraction distances on 360-412 m for loads of sawlogs and 0.43-0.66 l/m3sub (458-514 m) for loads of pulpwood. 61-62% of that fuel was consumed during loading and driving during loading. The forwarders consumed 0.23-0.38 l/100 m driving and the difference was only 10% with and without load. In the questionnaire survey, the fuel consumption averaged 0.62 l/m3sub (sawlogs and pulpwood, 318 m average extraction distance) for final felling (16-20 tonne forwarders) and 0.92 l/m3sub (644 m) for thinning (11-14 tonnes). An exception was 2.5 tonne forwarders that consumed only 0.35-0.37 l/m3sub (120-180 m). 89% of the extracted volume in the accounting data was from thinnings and the fuel consumption was in average 0.67 l/m3sub (100-200 m) for 9 to11 tonne forwarders.

More difficult terrain conditions, the use of tracks and wheel-chains and one more assortment in the questionnaire survey are the most probable reasons for higher fuel consumption than in the field study. At long extraction distances it is especially important to utilize the maximum load capacity to benefit low fuel consumption on m3 basis.

EN :

Two wood games are developed based on the structure and dynamics of the Beer Game. By introducing divergent and convergent flows in the supply chain, the relevance to the forest sector is increased. Using eight players in each run, the game is, in essence, a simulation tool that includes the human aspect in decision-making. The wood game is used to simulate the challenges that may be met when introducing a greater degree of customer orientation in the forest sector.

Performance is measured using total system costs, amplification of demand variation and basic statistics of order rates. Results from pilot experiments indicate that performance and predictability of the system are negatively affected by increasing the complexity of the supply chain. The level of demand distortion varies considerably between different games. Distorted demand signals may complicate the planning and execution of upstream operations.

EN :

The relative performance of two integrated machine concepts (combined harvesting / forwarding capabilities) was assessed against a conventional harvester / forwarder CTL system in a simulated thinning regime. Multiple-regression based on the simulation output was used in deriving time-consumption functions at the systems and machine level. Descriptive stand variables could be reduced to; harvest volume (m3/ha), stem volume (m3), lead distance (m) and object volume (m3/ stand) while maintaining acceptable statistical rigour (R2 > 0.95). The ability of one of the integrated machines to process logs directly onto the bunk provided it with an advantage that more than compensated for its reduced harvesting efficiency. Both integrated machine systems show a competitive advantage in forest structures with low object volumes and long or frequent relocations.

Factors negatively affecting forwarding productivity (e.g. long lead distances) favour the conventional two-machine system. A break-even economic analysis showed that integrated machines could present a feasible alternative to contemporary mechanised CTL systems.

EN :

During the last decade, the interest for a combined harvester forwarder (Harwarder) has increased and a quite rapid machine development has taken place in the Nordic countries. In 2000 a new prototype equipped with a rotatable and tiltable load carrier was built in order to enhance the possibilities for processing logs directly into the load carrier. A time study was done to test the hypotheses that 1) the rotatable and tiltable load carrier decreases total time consumption, and thus increases productivity, compared to a fixed load carrier, and that 2) the difference in time consumption between the two harwarder configurations is larger in final felling than in thinning. Results showed that harwarder productivity was increased by 6 per cent in final felling and 20 per cent in thinning by the introduction of a rotatable load carrier. In final felling with the fixed load carrier, the operator changed work method in order to process as many trees directly into the load carrier. It is suggested that this explains why the difference between machine configurations was lower for final felling than for thinning. Calculated harvesting costs for the harwarder were higher than the expected harvesting costs for a harvester and a forwarder in the studied stands. However, there is a large potential to increase harwarder productivity by both further development of the machine and the work methods used.

EN :

Shorthaul transport, known as secondary intermediate transport (SIT), is an additional transport phase within traditional secondary transport in South Africa. It originates at roadside landing or depot and terminates at another depot or rail siding (not the final destination). The use of SIT is forced by poor and steadily declining forest road conditions, to the extent that highway type vehicles are unable to reach roadside landings. This necessitates the use of intermediate storage sites, from which the timber is once again loaded and transported to its final destination.

A network analysis model and grid cell-based geographic information system were combined to analyse the various transport scenarios within three study areas in the KwaZulu/Natal Midlands of South Africa, employing SIT on poor, high-density forest road networks.

Results show the South African forest industry's average annual transportation cost penalty, by maintaining SIT, to be $US 4.32 million or $US 0.82/m3 over the cost of transportation over an improved road network using only secondary terminal transport. This cost differential does not account for the cost of upgrades required to eliminate the need for SIT. However a net present value cost analysis of the inclusion of road upgrade costs versus the average annual transportation cost savings and increased forest yield from decommissioned roads, maintains a positive financial benefit.

Economic analysis highlighted the need for reduced road network densities and for improvement of the remaining network. This would eliminate extended primary transport, multiple loading, unloading and storage by allowing highway vehicles to transport timber from compartment roadside to its final destination.

EN :

In Finland, the number of nurseries has been decreasing year by year, and it seems probable that in the near future this trend will continue. It can be assumed that greater economies of scale could also be achieved in Finnish seedling production by enlarging the size of production units [9, 10] . The management strategies used by a nursery company for long-distance seedling transportation were compared with different allocations of seedling production among nurseries. To determine the optimal transportation costs in different strategies for seedling production and planning of long-distance transportation, linear programming (LP) was applied. To manage spatial information, a geographical information system (GIS) was used. The current development towards seedling transportation managed by nursery companies seems to have marked advantages in the cost-effectiveness of transportation. The relative improvement in cost-effectiveness caused by centralized transportation strategy (CTS) compared to decentralized transportation strategy (DTS), which is the mostly used strategy in seedling transportation planning in Finland, varied from 13.0% to 36.5%, depending on the number of nurseries and the degree of specialization of production among them. These results will be useful for nursery companies and forest owners' associations (FOAs) when they evaluate the cost effects of production allocation, product specialization and systems of transportation management.

EN :

Four simulated procedures for scanning and bucking of 75 pruned and 75 unpruned radiata pine (Pinus radiata) trees were evaluated on the basis of productivity, costs, and value recovery. The procedures evaluated were: (a) a conventional scan where quality changes and bucking decisions were input by the machine operator, (b) a fully automated scan of the stem prior to optimisation and bucking, (c) a 6 m automated scan with 6.2 m forecast ahead, and (d) a 4.7 m automated scan with 7.5 m forecast ahead before optimal bucking took place. Cutting patterns for export and domestic markets were used in the simulations for optimally bucking each tree. After subtracting costs, net value recovery for the automated scanning methods was 5 to 8% higher than for a conventional scan. Based on the stand types and market conditions used in the analyses, breakeven capital investment costs for new scanning and optimisation equipment on mechanised processors could range between US$240,000 and US$450,000.