The work is dealing with the improvement of the knowledge of identification of trees and parts of forests predisposed to the bark beetle attack. The first part of the thesis deals with the basic issues, the second part presents a set of results from the presented research papers. In the field work, new methods are needed to speed up the identification process of predisposed trees, and the thermal camera may be used as one of the methods. We evaluated the potential of thermal camera to identify the forest predisposition to the bark beetle outbreak. From our results, we argue that thermal camera is useful in identification of not only infested trees or trees otherwise physiologically weakened, but also in other areas of plant physiology. However, it should be pointed out that the results are mainly influenced by measurement factors such as time (the highest differences were recorded in the morning), the place of measurement (the most accurate results are recorded at 1,3 meters) and the environmental factors (higher air temperature, higher solar radiation, higher difference between air temperature during the day and night). Our findings open new questions, the answer of which will be the subject of further research in the coming period.