Productivity of a John Deere Harvester Unit in Deciduous Stands

摘要

The aim of the presented paper was to determine the productivity of a John Deere 1070D harvester in deciduous coppices of iQuercus petraea /iand iFagus sylvatica/i, in thinnings over 50 years of age. The research area was located in Tribe? mountain ridge, western Slovakia. The terrain incline did not exceed 20%. The productivity of the harvester in oak stands was 9.97 msup3/sup.hsup?1/sup without downtimes (breaks, failures, etc.). Performance with breaks was 4.98 msup3/sup.PMHsup?1/sup (productive machine hour). The productivity of the harvester was influenced by a large portion of passes of the harvester, which constituted 23.47% of the time of the operating cycle. The large number of passes was caused by the fact that the operator did not respect the technologic process and a high portion of tree extraction (8.45%). Furthermore the productivity was decreased by frequent failures of the machine and downtimes, which could be prevented by proper and regular maintenance. The productivity in beech stands was 6.36 msup3/sup.hsup?1/sup without downtimes and 5.35 msup3/sup.PMHsup?1/sup with downtimes included. Lower productivity was caused by the numerous and thick branches and frequent presence of trees with multiple tree tops, ergo unsuitable structure of the stand. Absence of a worker with a chainsaw was considered to be a disadvantage, because this worker is often a necessity when harvesters operate in deciduous stands.