Dostawy drewna po wprowadzeniu normatywnych przeliczników gęstości drewna do określenia masy ładunku

The State Forests National Forest Holding that manages 77.1% of the forests in Poland intend to harvest over 40 million m³ of timber, which is supposed to supply the demand from some thousand timber processing companies. Introduction of a new normative for determination of the timber load weight as a result of multiplication its volume and wood density significantly changed timber transport regulations in 2012. The study analyzes the timber supply to a large (over 300 thousand m³ of wood per year) sawmill in the first half of 2012 and 2016. On the first date standard mass conversion indices were not implemented yet. We analysed whether there are significant differences in the timber deliveries between 2012 and 2016 with regard to monthly and weekly scale as well as in relation to the days of the week. In the first half of 2012 there was 4946 deliveries, which provided more than 126 thousand m³ of timber. In the same period of 2016 there was 6109 deliveries with total volume of 178 thousand m³. Increase in timber demand by 41% resulted in an increase in the number of transports only by 23.5%. Considering the distribution of the deliveries in each of 27 weeks, the average number of courses equal to 183 per week in 2012 and 226 in 2016. In first half of 2012, no courses were recorded in week 18, 26 and 27, while the highest number – in the week 16 (305 shipments). In 2016 only in first week there was no courses, and the maximum (312 deliveries) was reached in the sixth week. Average volume of weekly deliveries in 2012 amounted to 5234 m³, while in 2016 it reached 6595 m³. Maximum values equaled 7706 and 9026 m³ respectively. We noticed significant difference in the number of shipments and the volume of the delivered timber between the study periods, which results mainly from the increased production and demand.