The performance of polyclonal stands in short rotation coppice willow for energy production

The benefits of growing Salix spp. as a short rotation coppice in polyclonal (mixed) stands as compared to monoclonal stands are described. Increased yields are obtained from the polyclonal stands when compared to either the mean yield of component clones or the individual yields of any of the component clones grown in monoculture. Different component clones contribute different degrees to the increased yield. Salix viminalis Bowles Hybrid and S. Burjatica Germany showed the greatest positive response. In contrast, S. dasyclados performed poorly in polyclonal stands, both in stool survival and in growth of individual shoots. Some of the reasons for the improved growth in polyclonal plots and their practical benefits are discussed and recommendations are made.