In a floodplain forest on the Elbe river, the effects of elevation-considered as a surrogate for drought stress-and light availability on the mortality of germinants of pendunculate oak (Quercus robur), common linden (Tilia cordata), and red ash (Fraxinus pennsylvanica) were examined during the first growing season. For pendunculate oak, elevation and light availability interacted, resulting in mortality rates on higher elevated sites depending upon light availability; on lower elevated sites mortality was rather independent of light, probably because better access to water resources compensated for decreased light availability. By contrast, the mortality patterns of common linden and red ash highly depended upon light availability on all sites. These species-specific mortality patterns are explained by different capabilities to access water resources due to different root-to-leaf biomass ratios being at least four times higher for pendunculate oak as compared with the other species. This life history trait allows pendunculate oak germinants to better access the water resources than common linden or red ash.Light availability for germinants on these nutrient-rich floodplain sites is strongly reduced by competing ground vegetation. For forest management it is not recommended to create gaps for promoting natural regeneration on these sites until the end of the first growing season, in order not to enhance competition by pre-established ground vegetation.