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Mountain Logging

The International Mountain Logging and 10th Pacific Northwest Skyline Symposium was held 28 March - 1 April 1999 in Corvallis, Oregon, USA. The conference was sponsored by the Forest Engineering Department at Oregon State University and the International Union of Forestry Research Organizations. This symposium is convened every three years in Canada or the United States. This year there were about 250 participants from 20 countries representing every continent.

The proceedings are available from Oregon State University, 223 Peavy Hall, Corvallis, OR 97331, USA, E-mail:, Tel: +1 541 737 2818.

Many of the presentations at this symposium are of interest to a wide audience. The following are samples.

Forest Operations and Multiple Resource Management. Dennis Dykstra, CIFOR, Bogor, Indonesia, argued that non-timber forest products and resources are highly valued by society. In all parts of the world and at all levels of economic development, societies increasingly demand that forest managers consider the value of non-timber goods and services in making harvesting and silvicultural decisions. Operating technologies that reduce damage to residual vegetation, decrease soil disturbance, and improve timber recovery will benefit timber management while at the same time increasing substantially the value of the non-timber goods and services provided by forests.

Ground Based Harvesting Technologies for Steep Slopes. Hans Heinimann, Swiss Federal Institute of Technology, Zurich, Switzerland, discussed current machine concepts for ground-based steep-slope harvesting and their feasibility limits. He identified future prospects of harvesting technology development with special emphasis on slopes. He suggested that:

_ harvest planning will probably be based on a know-ledge-based engineering approach using algorithmic methods and artificial intelligence;

_ future system development should integrate materials handling functions into machine concepts and provide some intelligence in the behavior of machines;

_ legged locomotion has great potential to enlarge the range of terrain conditions for mechanized harvesting;

_ variability of both engineering design and operators have a huge effect on operational efficiency.

Walking Machine and Simulation Technology - New Applications for Advanced Operations. Antti Peltola, Plustech Ltd, Tampere, Finland, provided an update of the Plustech, six-legged walking harvester. He then discussed landscape and harvest machine simulators. Much like aircraft simulators, which have been used for many years, harvesting machine simulators are very economical to operate and provide maximum safety to personnel. Damage potential to property, machines and trees is minimized.

Seeking Solutions to Environmental Challenges. Kathleen Sullivan, Weyerhaeuser Co., Tacoma, Washington, USA, declared that during the past decade of change a considerable amount of the forest industry's resources and time have been spent designing and implementing ecologically friendly forest management systems. And that:

Environmental performance is as important to the forest industry as air safety is to the aircraft industry.

Reduced Impact Wood Harvesting in Natural Tropical Forests: Testing the applicability of the FAO model code of forest harvesting practice. Rudolf Heinrich, FAO, Rome, Italy, noted the importance of forests for biological diversity, non-wood products, cultural values and environmental services. Forest harvesting and engineering operations are the most important interventions in forest management that have profound impact on the composition of future forests. The FAO Model Code components are essential to sustainable forest management. He concluded that although ground-based wood transportation systems are still prevalent in tropical forests, it is pertinent to continue to carry out practical applied research to develop more cost efficient aerial (cable & airborne) transport systems that minimize environmental impacts and wood waste.

Plane-Type Logging Cable Systems in Japan - Past, Present, and Future. This paper by Yasushi Suzuki, Masashi Shiobara, Kochi University, Nankoku, Japan, and Miroru Kondo, Nagoya University, Nagoya, Japan, discusses three types of planar cable yarding systems. Whereas the usual skyline system can only vertically lift a log that is directly below the skyline, these systems can vertically lift a log from anywhere on the plane within the system boundary. The use of these systems in Japan was described and discussed. The authors concluded that simplicity is the most important factor for widespread use of a particular system type. Experienced forest workers will decline in number in the near future. Appropriate modifications of yarders will be necessary so that line tensions can be kept under safe limits automatically. Computerized devices to assist carriage position control are also desirable.

A triangular running skyline system, one of three plane-type cable systems used in Japan.

Monitoring Residual Stand Damage. Presentations by Eldon Olsen, Peter Matzka, Jim Kiser, Oregon State University, and Han-sup Han, University of Northern British Columbia. Policy in many regions of the world embraces thinning and other types of partial removal harvests. An assessment of the damage to residual trees has become very important. Traditional stand inventory sampling techniques are not the most efficient assessment procedure because the damage is concentrated along the extraction path. Surveys of residual tree damage have shown that as much as 60% of the damaged trees are within 3 m of the extraction corridors. This is especially true for skyline systems, but has also been found in ground based systems including mechanized cut-to-length systems. The reports on recent field experiences are summarized in the symposium proceedings. The findings included: observed levels of stand damage, recommended sampling procedures, and a computer assisted field monitoring system successfully implemented in private industry.

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