The Limber Jim case study : production and economics of a skyline system in a thinning/fuels reduction setting of a mixed conifer stand in the Blue Mountains of northeastern Oregon Public Deposited


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  • Forest managers in the Blue Mountains, of northeastern Oregon are currently faced with vast areas of forests with health problems and high fuel loadings. These conditions resulted from a combination of insect infestations, past management practices and the elimination of fire from the local ecosystems. These forests are now overstocked, diseased and contain vast amounts of dead woody debris on the forest floor posing a serious threat of large destructive fires. This paper presents an analysis of the economics and production of using a cable system to reduce thel loading, stand density, and minimize soil impacts. A combined thinning and salvage logging of the larger thels from the forest floorwas completed using a single-grip harvester to process the stems into logs and a medium sized swing yarder to transport the logs to landings. This combination of equipment was not common to the area and was chosen to minimize soil impacts. There were four units designated for skyline logging. Each unit had different terrain and stocking characteristics. Two units were logged uphill, one unit was logged downhill, and one unit was relatively flat. The harvester processed into logs all designated standing timber and any solid stems on the forest floor. A Diamond D210 swing yarder using a standing skyline, tailtrees, and intermediate supports was used to transport the logs to the landing. Production estimates 'pmh = productive machine hours = bone dry unit See Appendix H for conversion to S/green ton. 2 for the harvester and yarder were 19.24 tons/pmh' (9.33 cunitsfhr) and 10.40 tons/pmh (6.48 cunits/pmh) respectively. Total logging cost for the system (stump to mill) was $169,602. This equated to $73/ton ($1 15/cunit) of material removed. On a per acre basis, the cost was $2827 ($6985/hectare). Net revenue from sawlogs was $39,163.75 or $663.79 per acre. Net revenue from pulpwood was $97,785.79 or $1657.39 per acre. This resulted in a net loss of $32,653 or $544 per acre. Sawlogs represented 28.6% of the revenue, while pulpwood represented 71.4%. Gross weight from the project was 2332.69 tons with sawlogs representing 10.7% of the material removed, and pulpwood representing 89.3%. At the time of the study, pulpwood prices were $97.50/bdu2 ($46.93/green ton) and sawlogs prices were $425/mbf. Figure 6.2 gives an indication of the range of logging costs and the percentage of sawlogs needed to breakeven at different chip prices. The use of a skyline system in a thinning / fuels reduction setting proved not to be cost effective. Costs for a skyline system are generally higher than traditional ground based systems of logging in the area, but appears to have resulted in less soil impacts. Therefore, in areas where soil protection is the most important consideration, this logging system may be used, but careful consideFation needs to be given to the percentage of sawlogs designated to be harvested, the type of equipment used, and the current market conditions or the system may eperate-ataloss-. For this study, in order for the operation to breakeven, the percentage of sawlogs removed from the project needed to be 21.5% or higher.
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