The aim of this study was to assess the productivity of harvesters operating in coniferous and broadleaved stands under different silvicultural treatments and to identify the main factors affecting work efficiency under Polish forest conditions. The research was conducted in Scots pine Pinus sylvestris and European beech Fagus sylvatica stands subjected to final felling and late thinning. Productivity analyses were based on detailed time studies and expressed as harvested timber volume per operational working hour. A total of 2,042 trees with a total volume of 924.68 m3 were harvested during 29 h 12 min of operational working time. The mean volume of harvested trees in final felling stands of both species was similar, at approximately 0.6 m3, although greater variability in tree volume was observed in beech stands. Effective working time constituted the majority of operational time, ranging from 68.7 to 75.6%, with higher values recorded in final felling stands than in thinning operations. Harvester productivity varied significantly depending on tree species and cutting type. Productivity was higher in pine stands than in beech stands, regardless of cutting type. In final felling operations, productivity in pine stands was about 30% higher than in beech stands, while in late thinning the difference increased to nearly 65%. Operational productivity exceeded 45 m3·h–1 in pine final felling stands and 35 m3·h–1 in beech final felling stands, whereas in thinning operations it was approximately 33 m3·h–1 in pine stands and over 19 m3·h–1 in beech stands. Regression analyses confirmed a linear relationship between harvester productivity and the mean volume of harvested trees. Tree species and cutting type were also identified as significant factors influencing work efficiency. The results provide valuable, region−specific data on mechanised timber harvesting efficiency and confirm the need for productivity analyses under local operational conditions.
Kulak et al. (Wed,) studied this question.