Standardization of complementary work time in timber harvesting processes

One of the essential elements of work technology assessment is task performance time. In the working day structure, production times are crucial; however, under certain conditions, complementary work times can have a share of up to 30%. Accurate determination of the time structure of a work shift is very time consuming and requires time measurements using the methods of cumulative timing or snapshot observations. For this reason, the overall share of complementary work times in a work shift is usually estimated roughly, equally for all timber harvesting conditions. The aim of this study was to determine the impact of selected working environment factors on the share of complementary work times in a work shift, in technologies on the manual-machine and the machine levels. The analyses were carried out in 33 forest districts of the Regional Directorate of State Forests in Wrocław. Among forest contractors, surveys were carried out to analyse the time structure of a working day. For each forest district, analyses of environmental factors potentially relevant to the share of complementary work times in a work shift were carried out; these included field features, dispersion of stands, features of timber, area accessibility. The total share of complementary work times in the machine-level technology variant amounted to approx. 40% and was higher than the manual-machine technological variant, where this share amounted to approx. 35%. The models developed for standardization of the share of variability of complementary work times, in the case of the manual-machine technology level, took into account the share of timber assortments with the length of over 2.5 m as well as the share of upland and mountain sites. In the case of timber harvesting at the machine technology level, the standardization model included as significant the factors such as the share of coniferous forest sites, the number of forest complexes with an area of over 100 hectares, and the total length of roads. Therefore, the above features could be selected as decisive for the share of the complementary work time category out of the full set of environmental variables taken into consideration in the estimation of the time-consumption of timber harvesting processes.