The most commercially important community in which pedunculate oak can be found is the floodplain forest. Rejuvenation of pedunculate oak that could become a foundation for the natural stand regeneration however occurs only rarely in these site conditions, and even if it appears, it dies very rapidly in the shade of the parent stand. Some experts can see a reason to this phenomenon in water deficiency but most of them claim that the main reason to the decline of seedlings is insufficient light. The work was therefore focused on measurements and analyses which would enable to specify conditions (light conditions in particular) in which the self-seeded pedunculate oak can do well. In 1999 (year with extremely good crop of acorns), several sample regeneration plots were aligned which differed by insolation of the self-seeding or – in other words - by the reduction of the parent stand above the self-seeding. Oak seedlings growing in full insolation were growing best. In contrast, a full shade by the parent stand resulted in rapidly dying seedlings of up to 3 years, and the self-seeding with only a half light treat exhibited only a negligible increment and vitality loss. The growth of seedlings can be restored only in the case of improved light treat by a total elimination of stand shelter above them after the first year of life of the selfseeding. However, favourable conditions for a sound growth of the self-seeding can be generated only by a stand with the pedunculate oak of good morphological quality, which has been long prepared for natural regeneration (with a proper vertical and horizontal structure).