EN
Fast growing willow (Salix sp.) is grown on arable soils in Vistula river basin and it might be considered as an important source of renewable ecological fuel, especially in local scale. Yield of willow wood dry matter of six Salix viminalis forms grown on heavy alluvial soil amounted to 17.41 t · ha⁻¹ · year⁻¹, whereas Salix viminalis var. gigantea grown on moorsh soil yielded 15.62 t · haV · year⁻¹. Moisture content in willow wood varied ranging from 52 to 46% for one- and three-year shoots, respectively. Wood heating value amounted to 18.6 and 19.3 MJ · kg⁻¹, crude ash content 2.12% and 1.28%, for one and three-year shoots, respectively. Two high yielding and showing other beneficial features clones of Salix viminalis, namely 1047 and 1054, were selected. Mentioned forms, after trials focused on productivity, might be in close future recommended for growing on willow plantations. To answer an essential question - will the investment in innovative production of willow be profitable? - the energy balance and economic analysis seem to be necessary.