Australian researchers have shown that small actions can cause large productivity differences on the same machine.A study was carried out using two almost identical single-grip harvesters in Pinus radiata logging operations. The research compared the productivity of each harvester (Valmet 475EX with Rosin 997 heads and Dasa 4 onboard computers) under similar terrain conditions. Tree size varied between 1.8 and 2.5 m3. A selection of different sawlogs were being produced. The results found differences in the processing times of each machine. These differences were found to be the result of different operator working techniques. The main influencing factors were that the operator of the less productive harvester dragged out most trees (after felling), and cut discs on most trees to reset the length-measuring device. The dragging-out increased cycle time by at least five seconds per tree, as the operator waited for the tree to land, and then slewed the machine to get the tree into position for processing, while the other operator used the momentum of the tree by feeding the tree through the feed rollers and slewing the machine into position simultaneously. However, the operator did not drag trees of less than 1 m3 and the productivities of both machines were then similar. The researchers suggest increased formal training and refresher training to achieve optimal productivity.
The research, titled “A log-by-log productivity analysis of two Valmet 475EX harvesters”, was published in the International Journal of Forest Engineering, Vol. 25(1), 2014. The authors were M Alam, D Walsh, M Strandgard and M Brown. Access at http://www.tandfonline.com/doi/full/10.1080/14942119.2014.891668