The background of this study was the problematic situation the recent increased intermediate felling causes: It brings a lot of expenses to a customer, but the outturn of logging per harvester, however, is at a low level. The commissioner of this study is Metsäliitto Osuuskunta. The aim of the research work was by means of factory tests to find out the differences in quality between two methods of felling. One is, when pulpwood birch short logs are felled using a multi-stemming method and the other is, when trees are cut down normally, as single trees. The differences between these two methods of felling were analyzed and explained and the research results will be handed to Metsäliitto Osuuskunta. The research method was a triangulation research. It is based on describing and analyzing the target by means of statistics and numbers and consequently it gives the good tools for understanding its quality, special features and significant factors in a holistic way.

The research material was based on the field tests. All the material that was collected, was analyzed, differences between the measurement and quality requirements of short logs were being studied. The final results gave the possibility of counting the different dimensions that measured the differences between these two methods of felling. In this thesis the distributions between the short logs with undersize top diameter, those with defect in quality and as to the length dimension, were visualized and made concrete as relative results. The other results of the research are confidential.

The main sources for the theory applied in this thesis were those earlier studies found in the literature and on the Internet. In addition during the research process attention was paid to many details in different contexts and important observations were made. The actual functional research work took place the Metsä-Botnia chemical pulp mill of Äänekoski. The results of the thesis show that qualitatively the multi-stemming of the pulpwood short logs of birch trees does not differ from the felling of single trees. The conclusion is that the bundle- harvesting technique can be recommended and it is a good alternative when reprocessing this type of wood in factories. Special education and training for those using this technique might be needed in the future.