%0 Articles
%T Timber harvester operators’ working technique in first thinning and the importance of cognitive abilities on work productivity
%A Ovaskainen, Heikki
%D 2009
%J Dissertationes Forestales
%V 2009
%N 79
%R doi:10.14214/df.79
%U http://dissertationesforestales.fi/article/1862
%X The working environment of timber harvester operators has changed dramatically over the past fifteen years. The operator’s physical workload has decreased while the proportion of mental load has increased, as a consequence of the increased responsibilities involved in the cutting work. The decision making during the work has also increased and speeded up considerably. Therefore, the importance of the operator, with regards to harvester productivity, has been emphasized as a result of the equalization of the different harvester brands. For this reason, more and more attention is paid to the operator with the expectation of reaching certain productivity levels. This also places extra expectations on the operator’s training; especially in demanding cutting conditions, such as in first thinning, where the operator’s abilities are tested the most.

The principal objective of this research was to discover and describe a productive working technique for harvester work in first thinning and to improve harvester operator training by highlighting the problems of harvester simulators and determining the important cognitive abilities needed in harvester work. The work of six professional harvester operators was studied using numerous data collection methods: time study, working technique observation, helmet camera video recording, virtual harvester simulator cutting and psychological tests. In addition, 40 harvester operator students participated in the psychological tests.

The results indicated that when working productively, in first thinning conditions, the moving distance of the harvester head is minimized. In positioning the harvester head to a removable tree the positioning distance should be short. In felling a removable tree, the tree should be moved only the distance that fluent boom work necessitates. The work should be planned so that reversing is avoided and non-productive time, such as clearing of small trees, is minimal. From the fluent boom working point of view the results showed the operators’ consistent method to locate the harvester optimally according to the edge trees of the strip road. Based on this a productive working technique for harvester work in first thinning was created and described. A productive working technique can increase productivity by 10 to 15%. In addition, the handling of trees located in different places around the harvester was theorized. The results also indicated that the virtual harvester simulators are applicable for harvester training when the trainees are conscious of the limitations of the simulators. From the point of view of harvester operator training and operator selection the psychological tests indicated that productive and skilful harvester operating is not solely explained by one cognitive ability, instead, the mastering of different kinds of abilities appears to be more important. By combining the productive working technique with the operator training and taking into account the cognitive challenges faced in harvester work, for example, work planning and perception, the graduated students are likely to be more productive and ready to meet the challenges of working life.