The spruce licorice is one of the most dangerous pests in forests in Central Europe.The infested spruces are weakened and subsequently die en masse.Calamites caused by the spruce weevil (Ips Typographus (L.) are a current problem not only in non-native spruce monocultures, but also in natural spruces, as confirmed by the condition of forests in the Tatra National Park.The presented diploma thesis presents an overview of current knowledge about the most important factors that determine the spread of subtle insects in mountain forests.Similarly, it deals with the importance of temperature in the bark of infested trees for the course of developmental stages and the estimation of the development of the spruce lichen-eater population in TANAP.We determined the temperature in the bark using the PHENIPS phenological model on the basis of air temperature and solar radiation measured directly in the evaluated stands.Based on the air temperature, resp.We determined the theoretical course of developmental stages and the number of generations of the spruce bark beetle.We verified the expected swarming dates on the basis of catches in pheromone traps.