Diploma thesis analyses the development of mixed stand in conversion to a selection forest which was affected by the windthrow Žofia in 2014. This stand is a part of Pro Silva Donovaly object and it is located in the 6th altitudinal vegetation zone. Before the windthrow, the stand was in a conversion with the help of following generation. For this purpose, Baden shelterwood cutting was used. Measurements were made on the permanent research plot with dimensions of 50x50 m. Trees were divided into three categories: forest stand (dbh>8 cm), recruitment (dbh1-8 cm) and natural regeneration (height 20-130 cm). Tree species composition was determined by the importance value index. Annual height increment in the last 5 years was measured for individuals of spruce and fir with height between 1,3-3,5 m. Furthermore, light conditions were quantified with the use of hemispherical photographs. In this thesis, stand structure from 2013 was compared with the state from 2016. After the windthrow, massive decline of stem number was registered and growing stock fell approximately to 10% of the original value. Significant change was observed mainly in middle and upper layer. Evaluation of the importance value index showed decrease of spruce in favour of fir and beech. Measurements in 2018 revealed visible growth from the lower to upper categories as well as dynamics of the diameter classes and increasing growing stock. Current development suggests worsened conditions for growth of fir and increasing abundance of spruce and beech. The presence of rowan can have positive effect on further stand development. Light conditions were characterised by large variability and high values, which in most cases did not fall below 30%. Height increments of spruce and fir also had large variability. Spruce had higher height increment than fir, but difference is not statistically significant. Impact of diffuse radiation on the height increment was statistically significant only in case of fir. Impact of diffuse radiation on the natural regeneration was minimal and it did not significantly affect abundance of natural regeneration. Abundance of natural regeneration and height growth is probably not currently affected primarily by radiation. In terms of further development of the investigated stand, if appropriate silvicultural measures are taken, the selection structure will be restored. It was confirmed that structurally differentiated stand is able to mitigate the impact of windthrow.