Analysis of Optimized Semi-Mechanized Timber Harvesting Methods For Pine (pinus Sylvestris) In The German Federal State of Brandenburg

Analysis of optimized semi-mechanized timber harvesting methods for pine (Pinus sylvestris) in the German federal state of Brandenburg Maximilian Jakob, Ferréol Berendt, Tobias Cremer

The framework conditions for timber production in Brandenburg are changing due to climate change and the changing demands of society on the forest. The provision of ecosystem services such as carbon sequestration, water storage and filtration therefore plays an increasingly important role in forest management. Wood harvesting technologies and concepts must be adapted accordingly. Today, in Brandenburg the proportion of FSC-certified forests is increasing. As one consequence, max. 10 % of the managed forest area are allowed to be used as skid trail in the long term. Therefore, there is a need to adapt and optimize the present timber harvesting systems to the specific conditions of Brandenburgs pine forests with extended skid trail spacing. In autumn 2023 a harvesting operation was carried out in a 20 ha pine forest in Northeastern Germany, to investigate different timber harvesting systems under comparable conditions: Four timber harvesting systems were used, each with two different thinning approaches. Fully mechanized timber harvesting with 20 m skid trail spacing was implemented as a reference scenario. In three differing semi-mechanized systems, the trees outside the boom reach of the harvester were motor-manually felled. In addition, a skidder was used in one harvesting system to winch the logs to the skid trails. For the calculation of productivity and cost, a time study was carried out according to the methods described in REFA - Association for Work Studies and Business Organization. In addition, the following data were collected and analyzed: processed timber volumes, damage to the remaining trees, distance and slope of the skid trails, amount of wood that could not be processed and remained in the forest, as well as fuel consumption of the machines. Based on this, the presentation will give insights in the productivity and costs of the various timber harvesting systems. As well, it will be shown, to what extent the skid trail distances and the respective harvesting methods do have an influence on the damages to the remaining trees. Finally, results will be presented on whether the use of a skidder for winching the trees is worthwhile in relation to the amount of wood that can be processed additionally.