Volume 10, numéro 1, january 1999

EN :

What will future Canadian forestry operations resemble? In what context will workers, technicians and forest engineers work? A recent analysis of the technical, social and economic factors the Canadian forest industry faces can help us predict how operations will have to change to adapt to future demands. In this context, the paper focuses on outlining what forestry operations may be like in the next century.

EN :

This paper highlights the development and prediction of forest engineering and forest engineering education in China. The activities of forest engineering has changed significantly since the introduction of a market economy into China. Profitability and economic efficiency are emphasized. Techniques and education systems in forest engineering must not be transferred mechanically from other countries. They must match existing social, economic, and physical conditions. The importance of forests in supplying non-wood forest products such as water and soil protection, climate adjustment, honey, nuts, mushrooms, medical plants and wildlife need to be considered when decisions are made about forest engineering activities, such as forest harvesting. Forest operations, as an important part of integrated forestry, should be planned from the point of view of sustainability of both timber and non-timber forest products. It is evident that a concerted effort is needed to encourage forest development programs that harmonize interests in conserving forests as well as to wisely use the potential of the forest while maintaining its full regeneration capacity. All forest engineering activities, such as forest resource surveying and harvesting planning, forest road planning and construction, harvesting , post-harvesting site disposal, planting and protection and so on should serve the key purpose of sustainable forestry. In view of the forest quality decline in China, it is essential that forest engineering practices are carried out in a manner to guarantee the sustainability of the forest resources base. "The Natural Forest Protection Project”, just started in 1998 in China brings challenges and changes to forest engineering. The environmentally sound, low cost and high efficient techniques of forest engineering will be the spotlight of research in the future.

EN :

The forests and forestry industries within Japan are in a period of uncertainty and change. It must be the responsibility of not only government and industry but also research to identify problems and set the priorities solving these problems.

This paper presents the role of forest engineering research in forestry-oriented technology, and how our approach to research is changing with societal needs through a brief history of plantation forestry in Japan. This review of the research "movement" is based on the assumption that the quantity of published papers would be directly a function of their contributions to related technological development, but indirectly would be influenced by public understanding of research effort with the result of the performance of technology transfer.

Six different journals dealing with forestry-related research papers were surveyed. Almost thirty-eight thousand pertinent papers issued in the period from 1955 to 1995 were captured through bibliographical information services available in university libraries and government research institutes. A considerable difference in structure and trend of changes in the number of papers issued has been observed among them. Particularly, forest engineering research within about 10 years between 1970s and 1980s has fairly altered in structure, function and orientation. The increased social concerns for various environmental issues propelled researchers toward making major changes in research-oriented activities. One of the notable trends in this research movement was the growing diversification in research areas and related subjects through active introduction of associated disciplines. The tendency has more steadily continued with increasing competition through the entry of associated and/or cross disciplines, organizational and educational reform, and priorities for research objectives.

EN :

An increased interest in the use of shelterwood stands to promote regeneration has led to an interest in how singlegrip harvester productivity is affected by shelterwood cutting compared to clearcutting. A comparative time study of a large singlegrip harvester was made in a spruce stand in northern Sweden. Three treatments were used. Shelterwood cutting leaving: 1) a sparse stand, 2) a dense residual stand, and 3) clearcutting. Each treatment was replicated three times. Results show that productivity decreases from 64 m3 per effective hour in clearcutting to 54 and 41 m3 per effective hour when shelterwoods with 259 and 381 stems ha1, respectively, were retained.

EN :

Long seedling-feed times can restrict the performance of a planting machine. In this study feed times were measured in a pneumatic feed-test rig. Test variables were seedling type, air velocity and hose diameter. Feed-time histograms were then tested against chi-square distributions. Each accepted distribution was used for calculating the proportion of seedlings that could reach a planting head in time and the proportion arriving late, with respect to the machine-cycle time. The mean feed times for those two categories were then weighted together to obtain a total feed time. Two models for describing the total feed time, one for "normal" seedlings and one for "butt-ended" seedlings were constructed, with machine-cycle time, air velocity and fullness quotient as input variables.

EN :

When subjecting forest products to certification the total environmental load of wood harvesting machinery should also be assessed. In this study fuel, hydraulic oil and lubricant consumption in harvesting operations in Sweden has been examined by using machine data acquired through a questionnaire. The objectives of the study were to assess the contractor and forest company owned harvesters' and forwarders' average oil consumption in practical harvesting operations in Sweden, ascertain if the ownership and size of the machines give different consumption figures and estimate the use of environmentally acceptable hydraulic oils as well as the amount of oil spilled outdoors. Diesel consumption was found to be 935 l/1000 m3ub for forwarders and 1 167 l/1000 m3ub for single-grip harvesters. Hydraulic, transmission and chainsaw oil consumption was significantly higher in forest company owned harvesters while no significant differences were observed among forwarders. Hydraulic oil spillage was estimated for both harvesters and forwarders at 20 l/1000 m3ub. For felling and crosscutting trees a further 35 l/1000 m3ub of chainsaw oil is spilled. Ninety percent of the utilized hydraulic oil was environmentally compatible.

EN :

Algorithms for determining skyline skidding and tractor skidding distances on raster digital terrain models are introduced and presented. Modules named DOWN, UP, STRDOWN, STRUP were programmed in Turbo Basic language to work with a raster Digital Terrain Model. The DTM, interpolated from a set of digitized contours, and all other data were handled in the IDRISI GIS environment.

Implications of these algorithms are discussed, especially their advantages and disadvantages relative to the opening of forests, and more broadly forest operational planning. Flowcharts illustrating the method for calculating tractor and skyline skidding distance are included.

EN :

An interactive computer simulation program models stand, harvest, and machine factors and evaluates their interactions while performing felling, skidding, or forwarding activities. A stand generator allows the user to generate either natural or planted stands. Felling with chainsaw, drive-to-tree feller-bunchers, or harvesters and extraction with grapple skidders or forwarders are currently modeled in the system and others may be added. Simulations are performed by moving machine images within stand maps on the computer screen. The residual stand, machine running paths, and extraction travel intensity are recorded for later analysis. Examples of simulations with common logging machines are illustrated.

EN :

In 1983, chainsaw cuts to the leg accounted for 29% of all reported lost time accidents in the New Zealand logging industry. The introduction of protective legwear reduced this figure to 8% in 1986. Since this time chainsaw cuts to the leg have continued to account for more than 5% of all injuries. There were several possible explanations for this failure to eliminate chainsaw cuts to the leg, including the deterioration of the protective legwear over time. Therefore, two research projects were established. The first attempted to find out how long the legwear was able to protect the user at the level required by the New Zealand Standard. This research found that the legwear failed after 6 months use by loggers working in New Zealand plantation forests. The second project was established to determine which factors caused the deterioration of the legwear's protective properties. This project found that exposure to even small quantities of oil resulted in the legwear comprehensively failing the New Zealand Standards test.

EN :

The road junction location problems, first posited by Fermat and later generalized by Simpson, is a fundamental component of optimal network design. The barycentric resection formulas of plane surveying provide a solution of elegant simplicity to this problem. Prerequisite junction point angles for the application of the resection formulas are obtained directly from Launhardt's original analytical development of this fundamental problem in route location.