In this work we follow the bachelor thesis, where we dealed in detail with bionomics, methods of defense and control of Ips typographus. As we have used the bachelor thesis to estimate the development and population abundance in the phenological model of air temperature, which is only an approximate method, in this work, the bark temperatures measured directly on the seed are used. The extent of damage caused by sub-insects in soil areas has been unusual in recent years. Observing the impact of climatic conditions and, in particular, extreme events, along with the state of the stands and other factors influencing the spread of the underfed insects are a prerequisite for qualified estimation of the further development of mountain forests in Slovakia. Analysis of the sub-insect population size is based on the phenological model Phenips, which predicts the course of the developmental stages and the number of generations over a year based on the daily air temperature and tree bark. In the assessment of the size of the potential bark beetle populations, the status of the stands, especially the so- untreated calamity. For the assessment of the resistance of the stands, information on the condition of the surrounding stands is used, especially their species, age structure and the way of the present and future care.