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    Author(s): Bobby Lanford; Bryce J. Stokes
    Date: 1996
    Source: Forest Products Journal. 46(11/12): 47-53.
    Publication Series: Miscellaneous Publication
    PDF: Download Publication  (143 KB)


    A side-by-side comparison of two popular thinning systems, a skidder system and a forwarder system, was made during winter logging conditions in southern Alabama. The first report of this study addressed stand and site impacts of these two thinning systems. This report focuses on productivity and costs while thinning an 18-year-old loblolly pine plantation. The skidder system used a feller-buncher with a shear head followed by a grapple skidder that transported bunches of trees and delimbed them with a grade delimber. A loader/slasher combination processed trees into 7.5-foot lengths and loaded tractor trailers. The forwarder system used two machines: a harvester and a forwarder. The harvester felled, delimbed, and bucked trees into 7.5-foot or cut-to-length pulpwood. The forwarder loaded processed wood and transported it to setout trailers. Production rates were sampled using time and production studies for each machine in the two systems. Production rates and estimated costs were combined for each system to give overall system costs. System production was limited by the woods transport vehicles, the single skidder for the skidder system, and the forwarder for the forwarder system. Weekly production rates were 261 cords for the skidder system and 249 cords with cut-to-length wood and 200 cords with 7.5-foot wood for the forwarder system. Cost per cord was slightly lower for the forwarder system using cut-to-length wood as compared to the skidder system, a difference of $0.14, and higher for the forwarder system in 7.5-foot wood, a difference of $3.77.

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    Lanford, Bobby; Stokes, Bryce J. 1996. Comparison of two thinning systems. Part 2. Productivity and costs. Forest Products Journal. 46(11/12): 47-53.

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