We studied intensity of illumination in several submountain beech stands differing in stocking density. The measurements were repeated two times: in period without leaves (March 12, 2002) and in period of full foliage (August 27, 2001). Maximum values of light intensity, in period without leaves equally as in period of full foliage were recorded from 12:00–14:00 h, practically on all the plots. The absolute highest values were measured on open plot in August, and they represented 56.0 klx. In the spring measurement, we detected somewhat lower maximum values 52.0 klx. Optimum conditions in context of light amount were obtained on plot treated with medium strong cutting several years ago. The mean values on this plot were found to be 0.9 klx and 7.9 klx in summer and in spring, respectively. The least favourable light conditions were on the former clear cut where we recorded only 0.5 klx and 6.7 klx in summer and in leafless period, respectively. We found out that the influence of cutting intervention grade on illumination intensity on the individual plots was high significant. Comparison between the individual measurements resulted in finding that significant differences were only obtained in case of open plot compared with each of the other plots.