EN
The paper concerns forest populations of lady's slipper orchid (Cypripedium calceolus L.). The study sites were located in localities with the most numerous populations of Cypripedium calceolus L. in managed forests in Poland. The field studies were conducted in 2012 according to Natura 2000 sites protocols. The aim of studies was the determination of population structure of lady's slipper orchid, especially in indexes reflected number of flowering and fruit plants. The relations between above factors and environmental conditions expressed by ecological indicator values, cover of vegetation layers, species richness, stand age, and intensity of thinning were studies. The obtained results confirmed negative influence of understorey layer and positive influence of density of tree layer on the development of studied orchid populations. The increase in thinning intensity has not significant influence on protection status of Cypripedium calceolus.