The root system of pedunculate oak (Quercus robur L.) at the margins of regenerated stands

The paper aims to contribute to the determination of reasons causing the irregular growth of young pedunculate oaks occurring at the margins of naturally and artificially regenerated plots neighbouring with adult stands on alluvial sites. It presents analyses of aboveground biometric parameters, mortality, root system architecture of young trees, root density in the soil profile, global solar radiation and soil moisture content in dependence on the location of oaks at the northern, southern, eastern or western margins of the regenerated area and on the distance from the stand margin. The highest impact of the neighbouring adult stand is always recorded on the margin of the regenerated plot while its effect is weakening towards the plot centre, and fading away ca. 7 m behind the crown projection of adult trees. Regardless of the oak location (northern, southern, eastern or western margin), the cause is a high root density of marginal trees of the adult stand, which induces the critical lack of water under their crown projections.