Willow bark and wood as a source of bioactive compounds and bioenergy feedstock

Willow (Salix) is one of the available sources of renewable raw materials, which can be used in various branches of the medical, chemical and energy industry. However, its biomass should be used primarily for the production of high added-value substances. Therefore, the aim of this study was to assess the production potential of biomass (bark and wood), bioactive substance concentration and energy features of 10 willow genotypes cultivated in annual cycles. Our research found that the highest total biomass yield (13 Mg ha-1 y-1 d.m.) was obtained from the S. purpurea x S. daphnoides UWM 029 hybrid but the highest bark yield from S. americana UWM 094 (3.9 Mg ha-1 y-1 d.m.). The significantly highest salicin concentration was found in the bark of S. purpurea x S. daphnoides (approx. 29 mg g-1); the salicylic acid level was about ten times lower. The potential bioactive substance yield was affected by the bark yield per hectare. The highest salicin yield (over 92 kg ha-1) was obtained from both S. purpurea x S. daphnoides hybrids. The highest yield energy value of wood (191 GJ ha-1 y-1) was found for S. purpurea x S. daphnoides UWM 029. In conclusion two interspecies hybrids of S. purpurea x S. daphnoides UWM 029 and UWM 193 were found to be the most promising in terms of the analysed features. However, a full assessment of the practical use of the hybrids requires further research into the economic and environmental effects of willow cultivation and bioactive substances production.

Automated summary

Willow (Salix) is a renewable raw material that can be used in medical, chemical, and energy industries. This study aimed to evaluate the production potential of biomass, bioactive substance concentration, and energy features of 10 willow genotypes. The research found that hybrids of S. purpurea x S. daphnoides showed promising results in terms of biomass yield and bioactive substance production. Further research is needed to fully assess the practical use of these hybrids.