Epsilon Archive for Student Projects

Abstract

Today, there is a need of restoring forests to support the biodiversity in Sweden. There is a deficit of wounded and dead wood of different qualities, which many organisms depend on. Therefore, prescribed burning, point burning and debarking is used to increase the occurrence of dead wood of different qualities. In this study, the injury response in pine (Pinus sylvestris) was examined after the three nature conservation measures, two years after treatment. The primary focus has been on the resin impregnation in the wood. The study material was collected from two sites in Västerbotten. Discs were cut out at regular intervals from the pine stems, along the whole injured section, and studied in the lab. The result showed that the prescribed burning gave the most scattered pattern of resin impregnation along the height of the stem. The point burning resulted in the deepest resin impregnation and was located only at the base of the stem. The debarking led to a shallow resin impregnation, centered around the mechanical wound. The difference in impregnation depth between the two fire-based methods is explained by the difference in duration of the heating, as the point burning provided heat to the stem for nearly 1.5 hours. A strong correlation between the extent of dead phloem and cambium and extent of resin-impregnated wood was also found. For all treatments, increased number of resin ducts (likely induced by the trauma) were noticed in the annual rings that was grown after the injury. Also, a likely hydraulic disturbance (i.e. a dry area within the sapwood) was found in one of the prescribed-burned trees. The conclusion is drawn that the effect of the three nature conservation methods differs, but all support the creation of dead and wounded wood of different qualities, which should support biodiversity.