Treatment of birch plantations in southern Sweden with browsing repellents : effectiveness of Trico as a browsing repellent on birch over three seasons

Sammanfattning

Sweden is a forested country with 4 different cervid species. Browsing is a problem for Swedish forestry and there is a need for protecting seedlings. The main production species in Sweden is Norway spruce and Scots pine while birch is underused in Swedish forestry. However, there are signs of increased interest but there is an issue by birch being browsed by cervids. Trico is a browsing repellent that may address this problem and works using odour. This thesis attempts to answer the following questions: Does browsing repellent against cervids in Sweden when applied to birch in early summer last and function until fall and the following winter? Whether browsing repellent applied in the fall protect the birch during winter, and remain effective in the following spring? Does application on birch both in early summer and fall provide better protection compared to application once in either season? It is hypothesised that Trico will not influence other damages or seedling morphology. This study showed that Trico has worked as a browsing repellent against cervids for summer browsing. As there was no observed browsing during late fall and winter there was no need for repellants. Trico cover was sufficient in the spring inventory for seedlings treated in the fall but not for seedlings treated in summer only. This indicates that fall treatment may be active during next summer, but further research needs to be done on this. In this study Trico showed not to influence seedling morphology or other damage.