Productivity of seven clones of willow coppice in annual and quadrennial cutting cycles

In a field trial yield of oven dry matter of seven willow clones from own collection grown in two cutting cycles (annual and quadrennial) as well as plant biometric features were studied. Willow grown in annual cutting cycle planted at density of 40,000 cuttings ha−1 showed losses of 23.3% in case of hybrid Salix viminalis×Salix purpurea clone 1001 the higher losses were found while it was grown in quadrennial cutting cycle. It was found that on a very fertile soil (Mollic Fluvisols) under conditions of northern Poland all of studied genotypes in annual cutting cycle showed high productivity. Genotypes of species S. viminalis also maintain high yielding ability when cutting cycle was prolonged to 4 years. The highest yield irrespectively of cutting cycle was found S. viminalis for clone 1058.