A complex of field, laboratory and theoretical studies was conducted, including selection, laying and silvicultural-taxation and soil survey of sample areas, regular collection and physiological and biochemical analyses of pine needles samples, measurement of electrophysiological characteristics of trunk tissues, mathematical and statistical analysis of data and spatial modeling with GIS. Based on the data obtained, the state of the stands was studied. The results of the research allow us to objectively classify the trees in the studied sample areas according to the degree of stability to three successively changing states: normal, transitional and critical.