Production analysis of an excavator-based harvester : a case study in Finnish forest operations.

A production study was conducted for an excavator attached with a harvesting head under two stand conditions in northern Finland to determine and examine hourly productivity, unit cost, and working pattern. Before clearcutting, stand 1 was a natural stand composed of birch and spruce. Stand 2 was a pine plantation that was to be thinned a second time. Felled trees had an average diameter at breast height (DBH) of 17.8 and 15.8 cm, 7.64 m and 10.69 m in total merchantable height, and volume per tree of 0.18 and 0.20 m3, in stands 1 and 2, respectively. The results indicated that the productivity of this machine in forest operations was at the same level as that of Nordic purpose-built harvesters. Hourly productivity averaged 12.24 m3 per productive machine hour (PMH) in stand 1 and 10.43 m3/PMH in stand 2 and was affected primarily by DB H and the number of cuts or logs from a tree. Hourly costs were estimated at FIM 466.21/PMH ($84.8/PMH), which provided a cost estimate of FIM 69.47/m3 ($12.6/m3) in harvesting stand 1 and FIM 74.35/m3 ($13.5/m3) in harvesting stand 2. Working pattern of the excavator was also examined. The average boom reach was between 6 m and 7 m and the maximum vertical revolving angle was about 130 to 140 degrees. Moving distance between harvested stops averaged 16.11 m and the cutting width of a strip ranged from 8.0 to 10.0 m