The impact of the changing environment on the vitality of spruce mountain forests in Central Europe has become a more relevant problem in these decades (Lindner et al. 2010). Due to many abiotic (windstorm) and biotic (bark-beetles) co-occurring factors, which can have a negative impact on the health status of the spruce forests, we studied the physiological responses of natural spruce forests along the altitudinal gradient (D stand – 1100 m a.s.l., M stand – 1300 m a.s.l and U stand – 1500 m a.s.l.) of Lomnický peak, High Tatras, Slovakia (differently attacked by windstorm in 2004). Photosynthesis is a fundamental physiological process in plant cells reflecting the health status of the photosynthetic apparatus. We observed photosystem II stability using the analysis of chlorophyll a fluorescence in the spring (June) and the variation of photosynthesis-related pigments was assessed during the growing season. It was explored variation in assessed parameters in the context of the different levels of disturbance of the spruce stands (Strasser et al. 2004). Responses of the PSII showed the highest value of electron transport rate and the effective quantum yield on the U stand in the spring (June). D stand showed the highest content of assimilatory pigments in the spring (June). However, the content of assimilatory pigments was uniform during the growing season on this stand. The lowest content of these pigments was observed on the stand M during the growing season. The highest content of pigments was determined on the stand U at the end of August. Undamaged forest stands showed higher seasonal dynamics in the content of photosynthesis-related pigments compare to damaged stands.