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The current context of ecological transition and the fight against climate change have revived interest in short- rotation coppice (SRC) of woody crops for bioenergy or bioproduct purposes. To determine the growth and yield potential of different willow cultivars, plantations were established in five regions of Quebec (Canada) across a wide climatic gradient. The present study compares results obtained after six years of cultivation at two coppicing frequencies (two and three years). Although annual yields approaching 20 tons [ha.sup.-1] have been recorded at several of the study sites, little difference in the productivity of the tested cultivars was found, except for Salix viminalis '5027', which was generally less productive. Overall productivity was weakest at La Morandiere, the northernmost site. Neither frequency of coppicing lead to a difference in yields. At La Pocatiere, one of the coldest regions in this study, yields of cultivars were comparable to those recorded at the southernmost sites. Moreover, the highest cumulative yield after six years was recorded at that site with the cultivar 'SV1'. The fact that yields at most sites remain high after several years is indicative of the production potential of willow crops in SRC for Eastern Canada. Key words: willow crops, short-rotation coppice, biomass production, Salix cultivars, coppicing cycles Le contexte de transition ecologique et la lutte contre le changement climatique ont ravive l'interet pour les cultures sous taillis a courtes rotations (TCR) pour la bioenergie ou la production de bioproduits. Afin de determiner le potentiel de croissance et de rendement de differents cultivars de saules, des plantations ont ete etablies dans cinq regions du Quebec (Canada) le long d'un large gradient climatique. La presente etude compare les resultats obtenus apres six ans de culture selon deux frequences de recepage (deux et trois ans). Bien que des rendements annuels approchant les 20 tonnes par hectare aient ete enregistres sur plusieurs des sites, peu de difference dans la productivite des cultivars testes a ete trouvee, sauf pour S. viminalis '5027,' qui s'est revele generalement moins productif. La productivite globale etait la plus faible a La Morandiere, le site le plus nordique. L'une ou l'autre des frequences de recepage n'a pas conduit a des differences de rendements. Les rendements des cultivars plantes a La Pocatiere, une des regions les plus froides de l'etude, sont comparables a ceux enregistres pour les sites les plus au sud. De plus, le rendement cumule le plus eleve apres six ans a ete enregistre sur ce site, avec le cultivar 'SV1.' Le fait que les rendements demeurent generalement eleves apres plusieurs annees est revelateur du potentiel des cultures de saules en TCR pour l'Est du Canada. Mots-cles : Culture de saules, culture en taillis, production de biomasse, cultivars de Salix, frequence de recepage, Introduction The production of plants for bioenergy purposes reached its peak in the 1990s at the end of the last century. In northern Europe, especially in Sweden, thousands of hectares [...]

Salix interior Rowlee (INT) is a wide-ranging North American willow from the small taxonomic group Salix section Longifoliae, notable for its ability to form multi-stemmed vegetative stem colonies arising via root sprouts (RS) from a shallow horizontal root network. This study quantifies biomass production for both 1-year-old coppiced plants and the original 4-year-old plants established from dormant, unrooted stem cuttings, as well as for the RS stems associated with each ortet (original mother plant) using eight selected INT clones established on two distinct site types. Significantly greater coppiced and uncoppiced ortet stem dry mass was recorded on coarse-textured, shale rock overburden (SO); possibly due to significantly greater fertility, compared to adjacent gravel outwash deposits (GD), which had greater RS stem mass. The total stem dry mass (ortet + associated RS) was comparable across the two different site types for both the 1-year-old coppiced plants and the 4-year-old uncoppiced plants, showing rapid recovery of biomass growth and yield in the year following coppicing. Significant clonal differences, as well as site type * clone interactions, were found for ortet stem dry mass, especially on SO sites, indicating that clonal selection might be useful to increase biomass production on different site types. When expressed as a fraction of total stem dry mass produced on 2 m * 2 m biomass plots, the RS component represented a significant 57% of total stem dry mass per plot (ortet + associated RS) on GD sites and only 18% on SO sites. The use of colony-forming willows such as INT minimizes the need for periodic replanting, providing a cost advantage over conventional short-rotation, coppice-based woody biomass plantations using species that do not have the ability to produce new stems via root sprouting. This root-sprouting trait enables INT to rapidly colonize and spread on difficult-to-manage sites, making it suitable for use in land reclamation. Key words: biomass partitioning, coppice biomass production, clonal variation, root sprout stem colony formation, Salix interior, site effects. Salix interior Rowlee (INT) est un saule nord-americain tres repandu appartenant au petit groupe taxonomique Salix section Longifoliae, qui est remarquable par sa capacite a former des colonies d'origine vegetative composees de nombreuses tiges provenant de drageons issus d'un reseau racinaire horizontal peu profond. La presente etude quantifie la production de biomasse par des plants recepes ages d'un an et des plants d'origine ages de quatre ans qui se sont etablis a partir de boutures dormantes sans racines, et par des drageons associes a chaque ortet (plante mere d'origine) a l'aide de huit clones de INT etablis sur deux types distincts de stations. La masse seche des tiges d'ortet recepees ou non etait significativement plus grande sur un sol recouvert d'un schiste argileux a texture grossiere (SA), peut-etre en raison de sa fertilite significativement plus elevee, que sur des depots adjacents composes de gravier d'epandage (DG) qui soutenaient une plus grande masse de drageons. La masse seche totale des tiges (ortet et drageons associes) etait semblable chez les plants recepes d'un an et les plants non recepes de quatre ans sur les deux types de stations, ce qui indique une recuperation rapide de la croissance en biomasse et de la production au cours de l'annee qui a suivi le recepage. Des differences significatives de masse seche de tige d'ortet ont ete observees entre les clones et entre les niveaux d'interaction entre le type de stations et les clones, en particulier sur les stations SA, ce qui indique que la selection clonale pourrait etre utile pour augmenter la production de biomasse sur differents types de stations. Lorsqu'elle etait exprimee en proportion de la masse seche totale des tiges produites sur des parcelles de 2 m * 2 m, la composante des drageons representait 57 % de la masse seche totale des tiges par parcelle (ortet et drageons associes) sur les stations DG et seulement 18 % sur les stations SA. L'utilisation de saules formant des colonies tel que le INT minimise le besoin de replantation periodique, ce qui constitue un avantage en matiere de cout par rapport aux plantations conventionnelles de biomasse ligneuse a courte rotation qui utilisent des especes qui n'ont pas la capacite de produire de nouvelles tiges a partir de drageons. Cette caracteristique de drageonnement permet a INT de s'etablir et de se propager rapidement sur les stations difficiles a amenager, ce qui rend ce saule approprie pour une utilisation visant la remise en etat des terres. [Traduit par la Redaction] Mots-cles : repartition de la biomasse, production de biomasse en taillis, variation clonale, formation de colonies de drageons, Salix interior, effets de la station., Introduction The genus Salix (willows) is a large taxonomic group consisting of approximately 350 species worldwide (Argus 2010). Canada has 76 native willow species (Argus 2010), some of which have [...]

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. [...]

Genetic variation and population structure in biomass yield and coppice growth traits were assessed in seven native North American willow species (Salix amygdaloides (AMY), Salixbebbiana (BEB), Salix discolor (DIS), Salix eriocephala (ERI), Salix humilis (HUM), Salix interior (INT), and Salix nigra (NIG)) established together in common-garden field tests on two sites. Differences in biomass yield, coppice stem number, and average single-stem mass were significant at the site, species, population, and genotype (clonal) levels. There were also species x site interactions. Analyses of variance components for these traits showed that only 3%-5% of the total variation in these traits was due to site differences, whereas genetic variation at the species, population, and genotype levels accounted for approximately 10%-39%, 5%-13%, and 12%-23%, respectively. Populations were a significant source of variation in some willow species (e.g., AMY, DIS, ERI, and INT) but not in other species. Tree willows were less prolific in stem sprout production than shrub willows, and ERI coppices produced by far the highest number of stem sprouts per coppice. This multispecies investigation demonstrated strong species and clonal differences, but variation among populations within a species, although significant, was relatively small, indicating that major growth and yield gains can be made through proper species selection and clonal selection within local populations. Key words: biomass yield, coppice structure, genetic diversity, population genetics, willows. Les auteurs ont determine la variation genetique et la structure de populations pour des caracteres de rendement en biomasse et de croissance en cepee chez sept especes indigenes de saules d'Amerique du Nord (Salix amygdaloides (AMY), Salix bebbiana (BEB), Salix discolor (DIS), Salix eriocephala (ERI), Salix humilis (HUM), Salix interior (INT) et Salix nigra (NIG)) etablies ensemble en test comparatif au champ sur deux sites. Les differences de rendement en biomasse, en nombre de tiges par cepee, et en masse moyenne des tiges individuelles etaient significatives pour les effets relies aux sites, aux especes, aux populations et aux genotypes (clones). Des interactions espece x site ont egalement ete observees. L'analyse des composantes de la variance pour ces caracteres a demontre que seulement de 3 a 5 % de la variation totale chez ces caracteres etait due aux differences entre les sites, alors que la variation genetique chez les especes, les populations et les genotypes comptait pour respectivement environ 10-39 %, 5-13 % et 12-23 %. Les populations constituaient une source significative de variation chez certaines especes de saules (p. ex., AMY, DIS, ERI et INT), mais pas chez les autres. Les saules arborescents etaient moins prolifiques en ce qui a trait a la production de rejets que les saules arbustifs, et les cepees d'ERI produisaient de loin le plus grand nombre de rejets par cepee. Cette etude de plusieurs especes a mis en lumiere de fortes differences entre les especes et les clones. Mais la variation parmi les populations d'une meme espece, quoique significative, etait relativement faible, indiquant que des gains majeurs en croissance et en rendement peuvent etre obtenus via la selection d'especes et de clones appropries au sein des populations locales. [Traduit par la Redaction] Mots-cles: rendement en biomasse, structure des cepees, diversite genetique, genetique des populations, saules., Introduction Plant biomass production is seen as an opportunity to promote sustainable biofuels and reduce the effects of greenhouse gas emissions through carbon sequestration (Killeen et al. 2011; Searle and [...]

This essay argues that high medieval economic growth in Champagne and elsewhere in northern France encouraged a switch in the primary focus of woodland management from extensive silvo-pastoralism to intensive small wood production. For the first time in the thirteenth century, coppicing, short cycles of cutting and regeneration of trees capable of resprouting from stumps or trunks, came to dominate sylviculture as an intensively managed, market-oriented system, one that lasted for centuries. This essay thus provides a wider context for the late medieval and early modern French state's role in shaping forest exploitation. Royal officials did not so much innovate as respond to new market opportunities by appropriating and generalizing practices that had long existed in many regions. Before the sixteenth century few educated experts ventured into the details of woodland management, which remained largely the preserve of nonelite peasants, foresters, and woodmongers, the bearers of a traditional, orally transmitted ecological knowledge.