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Floodplain forests have become rare in Europe due to anthropogenic changes. A critical aspect of their restoration is reintroducing flooding via dike relocation, as implemented at the Elbe River near Lenzen/Germany. How forest development is influenced by dike relocation is still unclear and difficult to predict. Inside the dike relocation area at the Elbe River, most trees were planted. Due to high tree mortality, we asked if the relative elevation of the planted trees and thus the number of flooding days inside the relocation area was comparable to the prevailing flooding regime in the surrounding active floodplain. Therefore, the positions of Ulmus laevis, Quercus robur, and Crataegus monogyna individuals were recorded using a DGPS and merged with a digital terrain model. Subsequently, relative elevations and numbers of flooding days per year and growing season (averages for 2011–2017) were calculated. The most flooding tolerant species, U. laevis, occurred at the lowest sites and tolerated the highest number of flooding days, followed by Q. robur, and finally by the least flooding tolerant species C. monogyna. All three species occurred at lower sites inside the dike relocation area and were exposed to longer flooding durations compared to sites outside the area. This was due to the complex morphology of this area and its special flooding and flow dynamics, which differed from the conditions in the surrounding active floodplain. Although the mean flooding duration was within the growth range of hardwood floodplain forests (Ficario‐Ulmetum), most individuals may not have established at the planted sites under natural conditions. Therefore, we recommend not relying only on plantings but also allowing natural succession. Then, species that can cope with the hydrological site characteristics may also establish in the long term. [ABSTRACT FROM AUTHOR]

Soil seed banks are the ecological memory of plant communities and might represent their regeneration potential. This study examines the soil seed bank in hardwood floodplain forests of the biosphere reserve 'Valle del Ticino' (Northern Italy) to find out whether the natural forest vegetation can potentially be restored by the soil seed bank. We compared near natural forests of the phytosociological association Polygonato multiflori-Quercetum roboris with stands dominated by the nonnative tree species Robinia pseudoacacia and Prunus serotina in order to investigate whether the composition of the soil seed bank is significantly influenced by the composition of the main canopy tree species and soil properties. Soil seed bank samples were taken from 20 randomly selected plots in stands that were differentiated into four groups related to the dominant forest canopy species. The germinated plants were counted and their species determined. A total of 2,427 plants belonging to 84 species were recorded. The composition of the dominant tree species and soil parameters significantly influence the composition of the seed bank. The similarity with the standing vegetation was very low. Only 13% of the species in the soil seed bank represent the target vegetation. The low percentage of target species and the high percentage of nonnative species imply that the regeneration of near-natural forest vegetation from the soil seed bank is not feasible. Consequently, disturbances that may activate the soil seed bank should be minimized. Thus, we recommend stopping the mechanical removal of the nonnative tree species in the Ticino Park. [ABSTRACT FROM AUTHOR]