The variability in work volition of harvester's operators

anglais. Recognition of the structure and distribution of rest breaks taken by workers during a workday is particularly important at worksites characterised by a high level of energy expenditure, which is typical of most of the timber harvesting technologies. Introducing harvesters into the forest practice in the recent years, for which other tediousness, such as monotonous and repetitive work was recorded, makes the abovementioned issue even more actual. This paper aimed to determine the nature of variability in work performance within a working shift at the worksite of a harvester's operator, and to recognise the form, distribution and duration of rest breaks per particular periods of a workday. The studies were carried out in clear-cut and post-disaster pine stands. The authors assumed that the most significant determinant of work performance level at the worksite under scrutiny was the time of delimbing. For describing the variability of delimbing work times within particular periods of a workday, and the duration of rest breaks, fourth degree polynomials were used. A characteristic rhythm of work volition was revealed, which differed from the work curve developed by Graf. The structure of rest breaks recorded in these studies resulted from an increasing mental fatigue and escalating need for body regeneration. The research results indicated that the distribution of rest breaks within a working shift did not correspond entirely with the model system of work organisation.

anglais. timber harvesting, harvester, workday structure, work curve, work volition

15

331-331