The paper presents the work performance analysis of timber harvesting with the use of Highlander harvester produced by KONRAD Forsttechnik GmbH. The analysis was performed based on the timing of the working day. We also assessed the organization of the machine operation in the research area and its functional capability. The study was conducted in Miçdzylesie Forest Department, Nowu Wieś Forestry in fresh mixed mountain forest, where the machine acquired spruce. Timing was perfonned based on the registration of the machine operation on a video camera and the measurements of collected assortment. Based on the results of measurements it was found that organization of the machine operation was not the best. A one-shift work system and short duration of a shift caused that the effective working time occupied only 67.9% of the shift time (about 4 hours). This resulted in reduction of the operating perfonnance on a working day which was only 12,7 m3·h−1, while an effective high-efficiency was 18.7 m3·h−1.