Effects of cutting size on the growth and wood property traits of short-rotation coppice willows

Short-rotation coppice willows, which are commonly propagated with cuttings, are promising bioenergy resource crops. In this study, a field trial with a completely randomized block design was carried out with 787 clones from three full-sib pedigrees involving two shrub willow species. A total of 7083 cuttings were planted in the field, and the mass of each cutting was recorded correspondingly. The mortality rate, growth traits, and wood property traits of each cutting-propagated plant were measured throughout a complete growing season. The obtained data showed that heavier cuttings produced shoots with lower mortality rate, higher height, thicker ground diameter, and larger biomass production than lighter cuttings. The cutting mass significantly improved plant performance, especially at the early developmental stages. However, the cutting mass had no effect on the basic density and the main chemical composition (i.e., cellulose, hemicellulose, and lignin) of willow wood. This study provided essential information for improving the establishment of short-rotation coppice willow plantations. Key words: cutting size, plant growth, wood property, short-rotation coppice, willow. Les saules cultives en taillis a courte rotation, qui sont generalement reproduits par bouturage, constituent une ressource bioenergetique prometteuse. Dans cette etude, un essai au champ selon un plan experimental en blocs completement aleatoire a ete realise avec 787 clones issus de trois pedigrees biparentaux impliquant deux especes arbustives de saule. Au total, 7083 boutures ont ete plantees au champ et le poids de chaque bouture a ete note. Le taux de mortalite ainsi que les caracteres de croissance et de propriete du bois de chaque plant reproduit par bouturage ont ete mesures au cours d'une saison de croissance complete. Les donnees obtenues montrent que les boutures plus lourdes ont produit des plants qui ont un taux de mortalite plus faible, sont plus hauts, ont un plus gros diametre au sol et produisent plus de biomasse comparativement aux boutures plus legeres. Le poids des boutures a significativement ameliore la performance des plants, particulierement lors des stades initiaux de developpement. Cependant, le poids des boutures n'a eu aucun effet sur la densite basale et les principaux constituants chimiques (c.-a-d. cellulose, hemicellulose et lignine) du bois du saule. Cette etude fournit une information essentielle pour ameliorer l'etablissement des plantations de saule traitees en taillis a courte rotation. [Traduit par la Redaction] Mots-cles: dimension de coupe, croissance des plants, propriete du bois, taillis a courte rotation, saule.
Introduction Short-rotation coppice (SRC) is becoming increasingly important worldwide as bioenergy demands shift to woody biomass (Wright 2006). This trend entails managing wood plantations as sources of perennial energy crops. [...]