Cable skidding productivity was 289 ft.[.sup.3]/PMH (1.78 MBF/PMH) and unit cost was $27.0/cunit ($50.0/MBF).
Kluender and Stokes (1994, 1996) conducted a time study on a southern pine harvest consisting of manual felling, grapple skidding, and cable skidding. The harvest method ranged from clearcutting to single-tree selection and the proportion of basal area removed was used to measure harvest intensity.
[T.sub.ijklmn] = nth observation of the elemental times, cycle time, or hourly production of cable skidding,
-- Cable skidding delay was only observed 24 times during the field study.
Hourly productivity of cable skidding was between 80 ft.[.sup.3]/PMH (0.49 MBF/PMH) and 472 ft.[.sup.3]/PMH (2.91 MBF/PMH) and averaged 289 ft.[.sup.3]/PMH (1.78 MBF/PMH) (Table 4).
Estimates of hourly costs of chainsaw felling and cable skidding were computed using the machine rate method (Miyata 1980).
Skidding cycle time and travel loaded time as well as cable skidding productivity were primarily affected by turn payload but skidding distance was another major factor that also influenced elemental times and productivity.