Length accuracy of aspen logs harvested with CTL 40HW harvester head designed for broadleaved species

The paper presents results of length accuracy of aspen logs cut by UTC 150-6LS harvester on which a new CTL 40HW head, designed especially for broadleaved species, was mounted. Research was carried out in March 2007 in Forest District Kėdainiai in Lithuania where aspen wood was harvested at two different lengths: 2.4 and 3.0 m. The objective was to find out if logs from the top part of the trees will have a major length inaccuracy in comparison with logs obtained from the bottom part of the tree. 2.4 m logs were selected from the lower part of tree trunks with a minimal diameter of 13 cm, 3.0 m logs were cut from upper tree parts with a diameter range 6 – 13 cm. The results obtained showed that there was no statistical difference between the length accuracy of bottom and top logs. A slightly better mean length accuracy was found in logs from lower tree parts (shorter 2.4 m) with a deviation 0.03 m and a smaller standard deviation 0,029154258; there were only 7% logs of accurate length 2.4 m, 3% which were shorter and 90% which were longer. Top logs had a slightly bigger mean deviation 0.04 cm, but with a bigger standard deviation 0,064654; 16% of these logs were accurate, 29% were shorter and 55% were longer. Measurements of the middle diameter of logs showed that the mean for all logs was 12.8 cm (15.2 cm and 10.2 cm for bottom and top logs respectively). Harvesting of broadleaved; aspen; length accuracy, off-length logsVytauto Didžiojo universitetasŽemės ūkio akademij