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Abstract: In order to improve qualitative traits of harvestable biomass and enhance its conversion into second generation biofuels (e.g. bioethanol), much attention should be paid to manage woody-energy plantations. This work represents an attempt to estimate chemical composition of biomass at stand level in poplar plantations. Based on the relationship between chemical traits of stem cross-sections and the corresponding distribution of diameter classes within the whole plantations, three different harvesting cycles were compared in terms of biomass yield and chemical composition. Under 2-year rotation, the stand showed the lower biomass annual yield (11.7tDMha−1 y−1) and the lower cellulose (42.5%) and the higher lignin (22%) proportion. On the contrary, under the 4-year cutting cycle, annual yield was not only higher (18.4tDMha−1 y−1), but the biomass also presented the highest cellulose (51.6%) and the lower lignin (19%) share. These results suggest that different management practices, including the cutting cycle, may affect not only yields but also qualitative traits of harvestable biomass of poplar short-rotation coppice. [Copyright &y& Elsevier]

Limits in propagation are hampering the diffusion of giant reed cultivation for biomass. The objective of this study was to compare rhizomes and micropropagated plants with stem cuttings obtained in spring vs late winter (with and without side shoots, respectively) and immediately planted. A three-years field trial was carried out, assessing how rapidly giant reed establishes, and how its yield components (i.e. crop height, stem density, stem diameter) and its rhizomes develop over years depending on the propagation method adopted. Long-lasting variations in yield components depending on propagation were found. In the three years, biomass yield was steadily higher in rhizome-propagated stands (+64% than the average of the other propagation materials), while no significant interactions with the year of study were observed. Stems were thicker in rhizome-propagated and thinner in micropropagated plants, while cutting-propagated ones showed intermediate values. Micropropagation led to a significantly lower ratio between the biomass of rhizomes and the number of rhizome buds. Moreover, micropropagated plants were shorter (crop height: 34%), while stem density was nearly doubled: an inverse relationship between tillering and elongation was highlighted. Plants obtained from winter cuttings were taller than those obtained in spring, although the height difference was mostly achieved towards the end of the vegetative season. At initial growth stages, winter cuttings were slower than spring cuttings in increasing sprout density. Immediately-planted cuttings showed potential to replace micropropagated plants. In particular, cuttings obtained in spring , showed suitability for on-farm propagation, by means of collection from existing stands followed by direct planting. • Long lasting inverse relationship between stem density and elongation was found. • Micropropagation led to lower ratio between rhizome biomass and rhizome buds. • Rhizomes produced thicker stems, stem cuttings generally showed intermediate values. • Winter cuttings were slower than spring cuttings in increasing sprout density at initial stages. • Immediately-planted cuttings showed potential to replace micropropagated plants. [ABSTRACT FROM AUTHOR]