Abstract: The four cultivars of Swedish energy willow were used as materials to compare with Salix matsudana ‘9901’, the native willow cultivar. The germination ability after propagation by cutting was studied and the growth dynamic of sprout was monitored with the accumulation of biomass. The method of fuzzy membership function was used to evaluate them. The purpose was to select the fast-growing willow cultivar suitable for planting in Tianjin. The results showed that after cutting in early April, the great germination rate and more sprouts was observed on S. matsudana ‘9901’, followed by S. viminalis. With the 45° oblique insertion method, the number of sprouts on the dorsal side was more than that on the ventral side, which had the greatest influence on S. fragilis. In the whole growing season, the thickest base diameter of sprout was observed on S. viminalis and the largest length of sprout was observed on S. matsudana ‘9901’. The thinnest base diameter and smallest length of sprout were observed on the S. dascladus. The number of leaves per plant in S. matsudana ‘9901’ and S. viminalis was higher than others. Compared with S. matsudana ‘9901’, the number of the first branch of sprouts on S. viminalis was small, but the average diameter and length were larger. The annual biomass per plant of S. viminalis and S. matsudana ‘9901’ were higher, while there was no significant difference between them. The biomass of main stems and branches of the four cultivars of the Swedish energy willow accounted for more than 50%, while those accounted for 38.2% for S. matsudana ‘9901’. The fuzzy membership function method was used to sort as follows: S. viminalis > S. matsudana‘9901’> S.‘MesuNeko’> S. fragilis > S. dascladus. It is concluded that S. viminalis is the most suitable for cultivation in Tianjin.

Key words: fast-growing willow, cuttings, sprout, biomass, fuzzy membership function