Volume 18, numéro 1, january 2007

EN :

A total of 29 forestry best management practices (BMPs) were measured on 116 randomly selected sites harvested between November 2003 and March 2004 in West Virginia using four checklists on haul roads, skid trails, landings, and in streamside management zones (SMZs). Landowners were contacted to gain permission for site visits according to the random list. Data collected were analyzed statistically to examine the significant differences of BMP compliance rates among forester involvement, ownership, harvest method, and forest district. Results indicate that BMP compliance was generally better when a forester was involved with the harvest or on industry lands. Forester involvement, ownership, and harvest method did not significantly affect most of BMP compliance rates. BMP compliance on skid trails, at landings, and overall compliance by site differed significantly among six forest districts in West Virginia.

EN :

Hauling logs during wet weather on low-volume roads can be a significant source of chronic turbidity and fine sediments that may be detrimental to aquatic organisms including salmonids in streams. As a result, regulations governing wet-weather hauling in the western timber-producing states and British Columbia have become increasingly restrictive. A potential result of the changes in regulations is limited access to an increasing proportion of commercial forestland during the winter months. The cost of restricted hauling and harvesting is potentially a resource that could be made available to improve aggregate road surfaces to minimize hauling restrictions during wet weather. The objective of this research was to investigate the opportunity costs associated with regulatory restrictions for hauling timber on a forest road during wet weather. The regulatory restrictions set forth in the California Forest Practice Rules of 2004 were applied to the MacDonald-Dunn Research Forest at Oregon State University. Historic rainfall data were applied randomly over twenty 20-year simulation periods and harvesting and hauling activities were restricted accordingly. The estimated costs and revenue for a 20-year simulation period without wet-weather restrictions were compared to three management scenarios for harvesting and hauling with wet-weather restrictions to determine the opportunity costs associated with wet-weather restrictions. Dependent on the management scenario, wet-weather restrictions decreased total net revenue for the McDonald-Dunn Research Forest from 1.7 to 18 percent. From this analysis, opportunity costs (and total net revenue decreases) were smallest with the management alternative that involved the overtime use of equipment during periods when hauling and harvesting activities were not restricted.

EN :

A previous study introduced a forest road design model developed to simultaneously optimize horizontal and vertical alignments of forest roads using a Tabu Search optimization technique and a high-resolution Digital Elevation Model (DEM). In this study, surface erosion prediction was incorporated into the road design model, so that users can optimize horizontal and vertical alignments of forest roads while constrained by maximum allowable sediment delivery from roads to streams. The road alignment optimization model was applied to a part of the Capitol State Forest in western Washington state. The application confirms the potential of the model to determine forest road alignments in a way to reduce total road costs as well as sediment delivery to streams. This paper also discusses the effects of DEM resolution on forest road alignment optimization. The accuracy of generating ground profile and forest road alignments depends on the resolution and accuracy of the DEM. The study results suggest that a 10-m grid DEM might be inappropriate to use for the purpose of road design and alignment optimization due to the lower accuracy in its elevation representation.

EN :

This paper was motivated by the current concern of brake failure in off-highway log trucks descending steep grades and the lack of onboard weighing systems for off-highway log trucks. This paper considers using the leaf spring U-bolts as load transducers and is divided into two stages: preliminary strain measurement with a partially loaded off-highway tractor and finite element modelling (FEM) of a U-bolt from the tractor’s leaf spring suspension. Preliminary results showed that incremental strain at two locations on the U-bolt varied linearly with payload, for an incremental load of 22.5 kN. FEM of the U-bolt was carried out to predict the maximum incremental strain occurring on the U-bolt surface for an incremental load of 105 kN. Incremental strain on the top of the curved portion of the U-bolt was found to be relatively constant and close to the maximum level of incremental strain and is recommended as a preferred position for the strain gauges.

EN :

A saw-bar with a saw-chain is a common tool in both mechanized and motor-manual harvesting operations. The friction between the saw-bar and the saw-chain must be reduced by lubrication. A precise oil flow control can reduce the amount of oil needed. Traditionally, mineral oils have been used, but the use of biodegradable vegetable-based oils has increased. The goal of this study was to evaluate the lubrication characteristics at different oil flows of two vegetable-based and one mineral-based saw-chain oil. The study was done on an experimental rig with a saw-chain speed of 23 m/s and with pressure between the saw-chain and a rotating rubber roller. The temperature of the saw-bar was used as an indicator of the lubrication efficiency. The saw-chain tension was constant and independent of temperature. In general, increased oil flow resulted in a lower temperature. For rapeseed oil and pine oils, the results were consistently significant between oil flows of 2 and 6 ml/min. At an oil flow of 2 ml/min and 5 minute test time, pine oil resulted in the highest temperature (121°C, standard deviation [SD] 6.4) and at 6 ml/min the lowest temperature (99°C, SD 1.1) compared with the other oils. No difference in temperature was found between mineral oil and rapeseed oils at oil flows of 2 or 6 ml/min. An oil flow of 2 ml/min was found to be enough to prevent high temperatures for all oil types. The study method, with an adjustable experimental rig as the tool, was found to be suitable for studies on lubrication of the saw-bar and saw-chain.