The Gülzow short rotation plantation with poplars and willows was established
as a permanent field trial in 1993. Data from more than 21 years of management are available now. Biomass yields from seven harvests of the three-year rotation and three harvests of the six-year rotation were evaluated. This resulted in significant differences in yield depending on the species of tree, clone and rotation time. The evaluation method for the dry mass yields was converted to the quadratic regression in the course of the statistical evaluation, which has improved the meaningfulness and generalization
possibilities. The yields of the poplars are clearly higher than those of the willows on the Gülzow site. In addition to the annual dry mass yield, additional features such as location, water supply and tolerance against thicksetting and diseases are important for selecting a clone.