Characteristics and Significance of a Harvester Operators' Working Technique in Thinnings
Authors
Heikki Ovaskainen
University of Joensuu
Jori Uusitalo
University of Joensuu
Kari Väätäinen
Finnish Forest Research Institute
Abstract
Productivity levels between harvester operators have been noted to vary significantly, by up to 40% in similar stands. It is believed that differences originate from the operators cutting techniques, motoric skills, planning of work, experience, felling order of removable trees, decision processes at the working location, machine properties and the surrounding environment. The objective of this study is to examine and compare six harvester operators and to detect those features of working technique that improve and rationalise the work. Consequently, improving the basic working technique can raise average productivity. The harvester operators' work was examined by using the normal stopwatch study method and the operators' working technique was registered for each handled tree. Working technique observations were adjoined to stopwatch the study time units as a large matrix after data collection.
Results indicate that unnecessary stem movements in the felling phase should be avoided. The stem should be processed close to the stump so that the positioning-to-cut distance to next removable tree is short. This reduced positioning-to-cut time for the next felling. In processing, a productive operator can operate without big delays and the variations in processing times for same stem sizes are small. Furthermore, the productive operator avoids reversing when he is doing normal harvesting work.
