Abstract
In an experiment conducted in the spring of 2011, 3600 cuttings of 145 Salix taxa were cultivated, which were subsequently harvested after 1 year and analyzed for thermophysical and chemical properties. Statistical analysis followed by grouping of the objects enabled us to find significant differences between the Salix genotypes. Two different groups (of 35 and 110 varieties each) were found with average values of higher heating value of 19.75 and 19.27 MJ kg−1 d.w., respectively, while in terms of lower heating value three groups were identified (consisting of 39, 102, and 4 taxa), represented by average values of 18.27, 17.06, and 16.52 MJ kg−1 d.w., respectively. In our opinion, moisture content of fresh material (three groups with average moisture contents of 9.14%, 7.29%, and 4.47% d.w., respectively) is the main indicator distinguishing the above findings. The tested varieties were also divided into three groups according to their volatile matter contents (14, 121, and 10 genotypes with average values of 76.47%, 74.80%, and 72.97% d.w., respectively) as well as fixed carbon content (with 21.3%, 20.23%, and 19.08% d.w., respectively, for groups of 23, 110, and 12 taxa). Also three groups of varieties (11, 121, and 13 taxa) were distinguished in terms of the level of ash (4.16%, 2.77%, and 1.84% d.w., respectively). Differences in the elemental levels of C, H, and S in tested Salix taxa were found as well.