Säsongsvis avverkning : det operativa traktvalets påverkan på den säsongsmässiga uthålligheten i ett bolagsdistrikts traktbank

Abstract: Due to soft grounds in combination with seasonal variation in soil humidity, there is a lack of stands that are possible to cut during spring and autumn in some geographical regions. For Holmen Skog this sometimes means that a large proportion of the contracted private forest is cut during the winter when the ground is frozen. One consequence of this is that the proportion of winter stands in the stand bank of own forest increases while spring and autumn stands becomes a scarcity. This in combination with milder winters, especially when there is a long period of reduced bearing capacity in spring or autumn, means that the situation rapidly can become critical. The overall goal with this study was to generate basic data for decision support in the work to achieve a sustainable distribution between own forest and contracted private forest in the stand bank. The study took place at Holmen Skog, district of Umeå, during autumn 2007 and was based on interviews and an analysis of harvest planning and delivery data. The study showed that there is a problem with how the cutting is distributed between own and contracted private forest during the year and that it foremost is the proportion of winter thinning of own forest that has increased in the stand bank. Fore instance the proportion of thinning of own forest in the stand bank that could only be cut during winter increased from 24 % to 37 % between 2004 and 2007. Not all questions of interest have been possible to deal with in detail. Nevertheless, the study contributes with substantial new quantitative and qualitative knowledge on the matter and, thus, enables better understanding and analyses of the factors involved in the work of achieving a sustainable distribution of own forest and contracted private forest in the stand bank.