Helicopter Logging Productivity on Harvesting Operations in Southeast Alaska, Using Ecologically Based Silvicultural Prescriptions
2007
Christian, L.E. | Brackley, A.M.
This study examines production rates and costs for felling and helicopter yarding on eight units harvested in accordance with ecologically based silvicultural prescriptions in southeast Alaska. The prescriptions included harvesting to create gaps, harvesting to leave trees in clumps, individual tree selection, and combinations of these treatments. In combination, the treatments represented five levels of basal area (BA) retention. The levels of retention had irregular spatial arrangements caused by gaps and clumps that ranged from 0% retention (clearcut) to 75% of BA retained. Turn time (TT), as adjusted to a standardized distance, and turn weight were used as the basis for estimating productivity. There were statistically significant differences in adjusted TT, depending on the treatment. Areas with higher levels of removal tended to have lower adjusted TTs. With the exception of one unit with a short yarding distance, average turn weights increased as levels of retention decreased. Weighted average cost per thousand board feet (mbf) harvested was $322. The cost per mbf for cutting and yarding together ranged from $305 to $353.
اظهر المزيد [+] اقل [-]الكلمات المفتاحية الخاصة بالمكنز الزراعي (أجروفوك)
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