Production and Cost Comparison for Three Skyline Thinning Systems
Abstract:Cable thinnings were conducted in a Douglas-fir stand containing 350 trees/ac (average dbh 12 in.). Production rates and costs for a small and a midsize yarder were compared at a light (80 trees/ac) and a heavy (125 trees/ac) thinning intensity. Conventional yarding cost 11 to 12% less with the small than the midsize yarder, depending on thinning intensity. Conventional yarding cost 20 to 22% more in light than heavy thinning for the midsize and small yarders, respectively. This is due in part to increased number of landing and road changes required and smaller turn sizes in the light thinning. Prebunching with the small yarder and swinging with the midsize yarder, studied at the light intensity only, cost about the same as conventional yarding with the midsize yarder and about 9% more than conventional yarding with the small yarder. Gentle skyline chord slopes, large amounts of brush, and excessive mainline sag due to high ground-to-carriage clearance should be avoided where slack is pulled manually. We project that avoiding these conditions, operating with a smaller crew than was used in this study, and reducing delays could render prebunch and swing yarding less expensive than conventional yarding with either a small or midsize yarder and therefore more suitable for handling small-diameter wood. West. J. Appl. For. 3(4):120-123, October 1988.
Document Type: Journal Article
Affiliations: College of Forestry, Oregon State University, Corvallis, OR
Publication date: 1988-10-01
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- Each regional journal of applied forestry focuses on research, practice, and techniques targeted to foresters and allied professionals in specific regions of the United States and Canada. The Western Journal of Applied Forestry covers the western United States, including Alaska, and western Canada; WJAF will also consider manuscripts reporting research in northern Mexico that has potential application in the southwestern United States.
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