Overdue cleanings have for a long time been an important topic of discussion within the forestry sector. When stands that have not been pre-commercially thinned are reaching the level of commercial thinning, many problems occur in terms of decision-making and economical outcomes. These types of stands are commonly known as conflict-stands.
The work was carried out partly as an interview survey towards representatives from the forest sector and the energy sector, partly as a case study of conflict-stands situated in Böksholm, north of Växjö and in Tönnersjö east of Halmstad. The criteria for the studied stands were that they had to be dominated by Norway spruce and be in a severe status of “conflict”.
The aim of the interview was to get an overview of the situation today, and also analyse trends in terms of conflict stands. The reason for including interviewees from the energy sector was that extraction of bio fuel is regarded as a potential alternative to solve the problems with conflict stands.
The aim of the field-study was to make a survey of the structure in conflict-stands and to evaluate alternative treatments at the first thinning. The first strategy focused on the future development of the stand and was mainly carried out as a thinning from below. The second strategy focused on maximizing the economical profit and was mainly carried out as a thinning from above. The strategies were performed with two different outtakes of basal area, 20 respectively 35 %. The strategies were also carried out with an assumption that the first thinning was postponed five years after pre-commercial thinning. Furthermore, calculations were carried out with an assumption that the first thinning strategy was performed as an extraction of bio fuel. A limit in diameter between cleaning-stems and merchantable wood was set to 8 cm for all the strategies.
The interview survey showed that conflict-stands were a common problem. An increased performance of pre-commercial thinning seems to be expected in the nearby future. There was a general positivism towards bio fuel extraction as an alternative to traditional thinning, especially among the interviewees representing the forest companies. The energy sector was regarding the conflict-stands as a great potential, not only for themselves but for the forest sector as well.
Even though the benefits of first thinning differed a lot between the strategies, the variations in present value and soil expectation value were small. Focus on profit in the first thinning resulted generally in higher net present values and soil expectation values than focusing on good stand development. To carry out the cleaning and then postpone the thinning five years resulted in increased net present value (4,4 %) and soil expectation value (8,6 %) in the strategy that focused on high profit at first thinning. The variations in the strategy for good stand development were small. In the strategies focu...
