Round wood distribution logistics of the Bavaria State Forest Enterprise. [German]Original Title Distributionslogistik der Bayerischen Staatsforsten fur Rundholz.

摘要

The Bayerischen Staatsforsten (Bavaria State Forest Enterprise) harvests about 5 mill.m3 wood annually and supplies a broad spectrum of small, medium and large client enterprises. A central sales organisation markets three quarters of this volume and the 41 state forest enterprises serve regional customers with the remaining volume. In the last four years, logistical considerations increasingly influenced this distribution - technically the initiation of the outbound logistics consisting of sales planning, purchase request and distribution. In the 2010 German fiscal year, 2.9 mill.m3 of softwood were delivered free mill through central marketing with the distribution optimized to the greatest possible extent in the traditional way. The overall inter-regional distribution planning resulted in a considerable reduction in the total transport distance, but still differing from an optimal distribution. A suboptimal plan establishes very early non optimal (i.e. too far) transport routes from forest to mill. The subsequent actual dispatching can hardly change this allocation. An optimal annual plan would need to bring about a further reduction in the distance travelled, and hence a reduction in transport costs and CO₂ emissions. The optimal distribution can be achieved by solving the so-called transportation problem which F. L. Hitch-cock described in 1941 in a paper entitled "The distribution of a product from several sources to numerous localities''. The solution to the transportation problem entails the optimal allocation of products, in this case round wood assortments, which need to be transported from a number of sources (location in the forest, log piles) to many sinks (wood industry mills). When covering the mill's demands, the total distance of the transport routes is minimal. The transportation problem itself is a classical linear optimization problem, which involves the minimization of a linear function that is restricted by a series of linear equations or inequations. For a particular assortment, the objective function to be minimized [3] is derived from the distance matrix C [2] and the distribution matrix X [1]. Here the sources cover the demand at the sinks [4] and [5]. The supply from the wood sources corresponds furthermore to the demand at the sinks. The transportation problem is a suitable model for the distribution of the different assortments of the Bavaria State Forest Enterprise's planned softwood yield for the year 2010. The solution of the central Bavarian sales organisation was compared to an optimized solution. The optimization results in savings of 2.2 mill.km, or almost 12% of the total transport route. The average transport distance from forest to mill for the different assortments can be derived for an economic assessment of transport distances and sales proceeds. The optimized transport routes identified resemble river systems separated by watersheds. Conversely, for a particular assortment, optimized catchment areas for mills can be derived from the optimized transport routes. This spatial analysis of catchment areas assists strategic planning to identify regarding transport the optimal customer locations for the different assortments. Thus the paradoxical transport situation, in which two trucks transporting the same assortment in opposite directions pass each other en route, will no longer occur with optimized allocation. The depicted approach results overall in a clear reduction in transport distances and thus transport costs, but also in a reduction in CO₂ emissions from round wood transport.