Root anchorage of saplings and cuttings of woody pioneer species in a riparian environment

1. The root anchorage ability of saplings and vegetative propagules may be decisive for persistence of woody pioneers in the highly disturbed habitat of floodplains. 2. Vertical uprooting resistance was investigated in saplings of three floodplain pioneers of central Europe, Alnus incana , Populus nigra and Salix elaeagnos , at the near-natural River Tagliamento, north-east Italy. Uprooting resistance of planted cuttings of P. nigra and S. elaeagnos was studied at this site and in an experimental garden. 3. Uprooting resistance was lowest in saplings of A. incana , intermediate in P. nigra , and highest in S. elaeagnos . For cuttings, differences in uprooting resistance between species were evident only under floodplain conditions, where resistance was higher in P. nigra than in S. elaeagnos . This difference was related to better growth in P. nigra . 4. The anchorage ability of saplings may be one factor influencing the longitudinal and transverse zonation of species in floodplains, as S. elaeagnos is restricted to highly disturbed sites close to the main channel, whereas A. incana and P. nigra occupy more stabilized habitats. For vegetative propagules, in contrast, regeneration ability may be more important than uprooting resistance.