This master's thesis studied the effects of water table fluctuations and mechanical stress on the growth of riparian vegetation. Two groups of willow cuttings were grown under similar conditions except one group was subjected to fluctuating water levels (treatment C) while the other had a constant water level (treatment B). Treatment B developed slightly more above-ground biomass. Below ground, roots adapted to external forces by distributing to allow plant survival. Roots in treatment B grew deeper and in a narrow range near the minimum water level. Roots also showed less radial asymmetry in treatment B compared to treatment C under fluctuating water levels. The effects of mechanical stress had a minor impact under steady water levels.