Volume 17, numéro 1, january 2006

EN :

A vote-based computer system for decision support was developed in Finland for finding the most acceptable timber harvesting alternatives during the planning of thinning operations in forests under joint-ownership. The alternatives are combinations of a harvesting method, a harvesting system, and the time of each harvest. A lot of information is needed during the planning process. The system was found to be a useful tool for managing information flows and order and organization of the mathematical and analytical methods that are embedded to system’s modules. An advantage of this system is that it uses a module containing multi-criteria problem-solving methods. This makes the system’s contribution to sustainable forest management effective.

EN :

We used a simulation model to estimate the economic opportunity costs and the density of large stems retained for patch retention in two temperate oak stands representative of the oak/hickory forest type in the eastern United States. Opportunity/retention costs ranged from $321.0 to $760.7/ha [$129.9 to $307.8/acre] depending on the species mix in the stand, the logging technology used, and rotation lengths. The resulting capital recovery costs ranged from $12.8 to $30.4/ha/year [$5.2 to $12.3/acre/year] depending on the degree of retention desired, the logging technology used, and the species composition of the tract. Opportunity/capital recovery costs are greatest in stands that have high-value species mix, are harvested with low-cost logging technologies, and/or managed on longer rotations. The approach described in this paper can be used to help forest landowners, managers, loggers, and other decision/policy makers understand the opportunity/capital recovery costs and ecological benefits associated with patch retention.

EN :

Among the costs associated with timber harvesting in northern New England, those related to unused production capacity are among the most poorly understood. Yet research in other regions of the US suggests that idle logging capacity can impose significant costs on wood supply systems, including logging businesses and procurement organizations.

Mail surveys of logging business owners and representatives of wood consuming mills were used to understand unused logging capacity in the northern New England states: Maine, New Hampshire and Vermont. Over two-thirds of logging business owners said that they experienced unused production capacity in an “average” year. Weather, poor road conditions, equipment breakdowns, and mill-imposed quotas, were cited most often as causes of unused logging capacity. Results of this study have implications for logging businesses, procurement organizations, and wood supply system efficiency in northern New England.

EN :

This paper describes a pilot study of end connections for ultra-high molecular weight polyethylene 12-strand braided rope (synthetic rope) for use in timber harvesting applications. Fourteen different end connections for 14mm and 16mm diameter synthetic rope were developed and break tested to determine suitability.

Three types of end connections were evaluated: spliced, adhesives, and dry hardware. Spliced end connections provided consistent performance in breaking strengths. End connections with adhesive had variable strength performance and are therefore not recommended. Within the dry hardware group, the pinned nubbin and knuckle link provided the highest breaking strengths. Suitable end connections for forest operations were: buried eye splice, Whoopie Sling, long splice, rope clamps, knuckle link, pinned nubbin, and in limited applications, rope clamps. Further research and development is needed on these six concepts with larger sample sizes and under testing and operating varied conditions.

EN :

A selection of the results from a comprehensive field and laboratory study on the impact of mechanised harvesting operations on a forest soil in New Zealand are presented. The season during which machine trafficking took place (“dry” and “wet”), machine type, and number of passes (from 1 to 30) were the input variables. Soil response was measured with pedological and geotechnical field and laboratory testing procedures. It was determined that although the soil was in some treatments heavily disturbed, it was not compacted, given that the natural water content was well above the laboratory determined optimum water content for compaction. Practical implications are discussed.

EN :

Shovel logging has become a popular logging system in the western United States due to its high productivity. Its low ground pressure and single pass, often on a matt of limbs result in little ground disturbance. Despite this increasing popularity, there have been few operational studies of shovel logging. This paper describes the optimal road spacing problem for shovel logging using a serpentine pattern on gentle terrain. A mathematical model for shovel logging is presented for two cases (1) to minimize the sum of shovel yarding costs plus road costs from the landowner’s point of view and(2) to maximize profits from the point of view of a logging contractor. For the operating conditions assumed, the optimal shovel yarding distance is four swings when shovel yarding plus roads costs are minimized and three swings when logging contractor profit is maximized. For the example data, the model results demonstrate the flexibility of shovel logging in that there is little difference between total road construction plus skidding cost from the optimal number of swings to as many as six swings. Sensitivity analysis was performed on road cost and volume per ha and support the stability of the solution with the minimum logging cost occurring at four swings with just a small difference for as many as six swings over a range of road construction and volume removals.