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Assisted gene flow according to expected climate gradients is considered as a forest management strategy to mitigate impacts of environmental change on forest growth. However, the effects of seed translocation on wood properties and lumber quality remain unknown. This study evaluated the effect of provenance origin on lumber production and quality at rotation age in two white spruce provenance trials established in contrasting environments in eastern Canada. Based on 108 sample trees, which resulted in 943 pieces of lumber, average volume production per tree at the southernmost site was twice that of the production at the northern site. Provenance had a significant influence on growth and lumber strength in the first sawlog but had no effect on lumber stiffness and wood density. Although visual grade yields of No. 2 and better were high in both trials (over 86%), the machine stress rated (MSR) grade potential and percentage of lumber that met the bending stiffness design values of the visual grades were generally low (12%-26%). Hence, plantation-grown lumber should preferably be machine stress rated to ensure its fitness for structural applications in buildings. Management strategies aiming to efficiently sequester carbon should primarily maximize volume productivity in northern sites, as moving seed sources north still reduces provenance productivity, while breeding programs should aim to prevent decrease in lumber stiffness due to augmented productivity and shortened rotation cycles. Key words: assisted migration, lumber visual grade, provenance trial, MOE (stiffness), MOR (strength), wood density, tree breeding Le flux genetique assiste, selon les gradients climatiques prevus, est considere comme une strategie de gestion des forets visant a attenuer les impacts des changements environnementaux sur la croissance des forets. Toutefois, les effets de la translocation des graines sur les proprietes du bois et la qualite des sciages demeurent inconnus. La presente etude a evalue l'effet de l'origine de la provenance sur la production et la qualite du bois d'reuvre a un age de rotation dans deux essais de provenance d'epinettes blanches etablis dans des environnements contrastes dans l'Est du Canada. Fonde sur 108 arbres echantillons qui ont produit 943 pieces de bois d'reuvre, la production moyenne en volume par arbre sur le site le plus au sud etait le double de la production du site au nord. La provenance a eu une influence significative sur la croissance et la resistance du bois d'reuvre dans la premiere bille de sciage, mais n'a pas eu d'effet sur la rigidite des sciages et la densite du bois. Meme si les rendements en grades visuels No. 2 et meilleur etaient eleves dans les deux essais (plus de 86 %), le potentiel de classer les sciages dans les categories de bois MSR (bois evalues par contrainte mecanique) et le pourcentage de bois d'reuvre qui respectait les valeurs de conception de la rigidite en flexion des grades visuels etaient generalement faibles (12 % a 26 %). Par consequent, le bois d'reuvre qui a pousse en plantation devrait de preference etre classe par contrainte mecanique afin d'assurer sa conformite a des applications structurales dans des batiments. Les strategies de gestion visant a sequestrer efficacement le carbone devraient avant tout maximiser la productivite en volume dans les sites du nord, puisque le deplacement des sources de graines au nord reduit toujours la productivite de la provenance, alors que les programmes de selection devraient viser a prevenir la diminution de la rigidite du bois d'reuvre en raison de l'augmentation de la productivite et de la diminution des cycles de rotation. [Traduit par la Redaction] Mots-cles : migration assistee, qualite visuelle du bois d'reuvre, essai de provenance, MOE (rigidite), MOR (resistance), densite du bois, amelioration des arbres, Introduction Canada's forest economy has largely developed around the utilization of abundant, high-quality, but largely unmanaged softwood resource (Barbour and Kellogg 1990). However, the increasing pressure on fibre resources from [...]

The increased pressure on timber supply due to a reduced forest land base urges the development of new approaches to fully capture the value of forest products. This paper investigates the effects of knowing the position of knots on lumber volume, value, and grade recoveries in curve sawing of 31 white spruce (Picea glauca (Moench) Voss) and 22 jack pine (Pinus banksiana Lamb.) trees. Internal knot position was evidenced by X-ray computed tomography (CT) imaging, followed by the application of a knot-detection algorithm allowing log reconstruction for use as input in the Optitek sawing simulation software. Comparisons of the three levels of sawing optimization (sweep up, shape optimized, and knot optimized) revealed that considering internal knots before log sawing (e.g., knot optimized) generated 23% more lumber value for jack pine and 15% more for white spruce compared with the traditional sweep-up sawing strategy. In terms of lumber quality, the knot-optimized strategy produced 38% more pieces of grade No. 2 and better in jack pine and 15% more such pieces in white spruce compared with the sweep-up strategy. These results indicate a great potential to increase manufacturing efficiency and profitability by implementing the CT scanning technology, which should aid in developing a strong bioeconomy based on an optimized use of wood. Key words: X-ray computed tomography (CT scan), sawing optimization, knots, sweep, lumber recovery. La pression accrue sur l'approvisionnement en bois causee par la reduction du territoire forestier exige qu'on developpe de nouvelles approches pour tirer la pleine valeur des produits forestiers. Cet article etudie dans quelle mesure le fait de connaitre la position des nreuds peut ameliorer le volume, la valeur et la classe du bois d'reuvre recupere avec le sciage courbe de 31 tiges d'epinette blanche (Picea glauca (Moench) Voss) et de 22 tiges de pin gris (Pinus banksiana Lamb.). La position des nreuds dans le bois a ete detectee par tomodensitometrie dont les donnees ont ete traitees avec un algorithme de detection des nreuds permettant la reconstitution des billes qui sert par la suite d'intrant dans le logiciel d'optimisation du sciage Optitek. Les comparaisons de trois degres d'optimisation du sciage (courbure maximale de la bille dans l'axe vertical, optimisation basee sur la forme, optimisation basee sur la dimension et l'emplacement des nreuds) ont revele que le fait de tenir compte des nreuds avant de scier les billes (p. ex. optimisation basee sur la dimension et l'emplacement des nreuds) a permis de produire du bois d'reuvre qui avait plus de valeur, soit 23 % dans le cas du pin gris et 15 % dans le cas de l'epinette blanche comparativement a la strategie traditionnelle de sciage (courbure maximale de la bille dans l'axe vertical). En termes de qualite du bois d'reuvre, la strategie d'optimisation faisant intervenir les nreuds a produit plus de pieces No 2 et meilleur, soit 38 % dans le cas du pin gris et 15 % dans le cas de l'epinette blanche comparativement a la strategie traditionnelle. Ces resultats indiquent que l'implantation de l'imagerie tomodensitometrique a un fort potentiel pour augmenter l'efficacite et la profitabilite de la transformation, ce qui devrait contribuer a developper une solide bioeconomie basee sur une utilisation optimale du bois. [Traduit par la Redaction] Mots-cles: tomodensitometrie, optimisation du sciage, nreuds, courbure, recuperation du bois d'reuvre., Introduction Canada is facing a reduced forest land base due to increasing natural and climate-related disturbances, including wildfire and pests, and societal decisions leading to forest protection or non-timber uses [...]

X-ray computed tomography (CT) of logs means possibilities for optimizing breakdown in sawmills. This depends on accurate detection of knots to assess internal quality. However, as logs are stored, they dry to some extent, and this drying affects the density variation in the log and therefore the X-ray images. For this reason, it is hypothetically difficult to detect log features in partially dried logs using X-ray CT. This paper investigates the effect of improper heartwood-sapwood border detection, possibly due to partial drying, on knot detection in jack pine (Pinus banksiana Lamb.) and white spruce (Picea glauca (Moench) Voss) logs from New Brunswick, Canada. An automatic knot detection algorithm was compared to manual reference knot measurements, and the results showed that knot detection was affected by detected heartwood shape. It was also shown that logs can be sorted into two groups based on how well the heartwood-sapwood border is detected to separate logs with a high knot detection rate from those with a low detection rate. In that way, a decision can be made whether or not to trust the knot models obtained from CT scanning. This can potentially aid both sawmills and researchers working with log models based on CT. Key words: CT scanning, jack pine, knot detection, white spruce. La tomographie aux rayons X assistee par ordinateur (TO) des billes offre la possibilita d'optimiser le debitage dans les scieries. Cela repose sur la precision avec laquelle les nreuds sont detectes pour evaluer la qualite interne. Cependant, lorsque les billes sont entreposees, elles sechent jusqu'a un certain point et cela influence la variation de la densite dans les billes, et par consequent les images radiologiques. Pour cette raison, il est hypothetiquement difficile de detecter les caracteristiques dans les billes partiellement sechees a l'aide de la TO. Cet article etudie l'effet de l'erreur de detection de la limite entre le bois de creur et le bois d'aubier, potentiellement attribuable au sechage partiel, sur la detection des nreuds dans des billes de pin gris (Pinus banksiana Lamb.) et d'epinette blanche (Picea glauca (Moench) Voss) provenant du Nouveau-Brunswick, au Canada. Un algorithme de detection automatisee des nreuds a ete compare a des mesures de reference de nreuds effectuees manuellement. Les resultats ont montre que la forme du bois de creur qui est detectee influence la detection des nreuds. Il a egalement ete demontre que les billes peuvent etre reparties en deux groupes sur la base de la justesse de la detection de la limite entre le bois de creur et le bois d'aubier, ce qui permet de separer les billes chez lesquelles le taux de detection des nreuds est eleve de celles chez lesquelles le taux de detection des nreuds est faible. De cette facon, on peut prendre la decision de faire confiance ou non aux nreuds modelises obtenus avec le balayage par TO. Cela peut possiblement aider tant les scieries que chercheurs qui utilisent la modelisation des billes fondee sur la TO. [Traduit par la Redaction] Mots-cles : balayage par tomographie aux rayons x assistee par ordinateur, pin gris, detection des nreuds, epinette blanche., Introduction As industrial X-ray computed tomography (CT) scanners were introduced to the market a few years ago (Guidiceandrea et al. 2011), new opportunities for optimizing production in sawmills have arisen. [...]

In the eastern Canadian boreal forest, long fire return intervals lead to over 60% of stands having an irregular, uneven-aged structure, which is associated with slower growth. The aim of this study was to examine the effect of stand structure on the clear wood mechanical properties of black spruce (Picea mariana (Mill.) B.S.P.). A total of 128 trees were destructively sampled from stands of regular and irregular structure across Quebec, Canada. Nonlinear mixed-effects models were developed for each stand type to describe the variation in modulus of elasticity (MOE) and modulus of rupture (MOR) in small defect-free samples as functions of cambial age and annual ring width. Mechanical properties were strongly related to cambial age, with a smaller influence of ring width. After accounting for these variables, both MOE and MOR were higher in samples from stands of regular structure, although differences were less pronounced in the upper stem compared with breast height. The fixed effects of the models explained between 34% and 53% of the variation in mechanical properties. A higher incidence of mild compression wood in trees of layer origin may explain the observed differences between stand structures. Resume : Dans l'est de la foret boreale canadienne, de longs intervalles entre les feux font en sorte que 60 % des peuplements acquierent une structure irreguliere et inequienne qui est associee a une croissance plus lente. Le but de cette etude etait d'examiner l'effet de la structure de peuplement sur les proprietes mecaniques du bois sans defauts d'epinette noire (Picea mariana (Mill.) B.S.P.). Au total, 128 arbres ont ete echantillonnes de maniere destructive dans des peuplements de structure reguliere et irreguliere a travers le Quebec, Canada. Des modeles non lineaires mixtes ont ete developpes pour chaque type de peuplement afin de decrire les variations du module d'elasticite (MOE) et du module de rupture (MOR) en fonction de l'age cambial et de la largeur des cernes annuels dans des petites eprouvettes depourvues de defauts. Les proprietes mecaniques etaient fortement reliees a l'age cambial, et dans une moindre mesure par la largeur de cerne. Apres avoir tenu compte de ces variables, le MOE et le MOR etaient plus eleves dans les echantillons provenant des peuplements de structure reguliere, bien que les differences fussent moins prononcees dans le haut de la tige qu'a hauteur de poitrine. Les effets fixes des modeles ont explique entre 34 et 53 % de la variation des proprietes mecaniques. Une incidence plus elevee du bois de compression de moindre severite dans les arbres d'origines de marcottes pourrait expliquer les differences observees entre les structures de peuplement., Introduction Wood from the old-growth, unmanaged Canadian boreal forests mainly supports a value chain dedicated to commodity products such as visually graded lumber and pulp and paper (Antal and Micko [...]

Abstract: A naturally regenerated jack pine (Pinus banksiana Lamb.) trial established in 1966 in New Brunswick was studied to determine how three precommercial thinning intensities (1.22 m x 1.22 m, [...]

Northern hardwoods are an ecologically and economically important forest type in eastern North America. Historically, the hardwood supply came from old-growth forests dominated by large-diameter trees. Unfortunately, the repeated removal of high-quality trees has substantially degraded hardwood forests and reduced the profitability of the primary manufacturing sector. In this context, forest managers need tools to guide silvicultural investment decisions and to estimate pre-harvest stand value based on forest inventories. The objective of this study was to evaluate the performance of classification systems and measured variables used at the tree level to predict sawn product volumes of sugar maple (Acer saccharum Marsh.), yellow birch (Betula alleghaniensis Britton) and American beech (Fagus grandifolia Ehrh.). We developed statistical models to estimate the volume of lumber products, pulpwood, sawdust and residues based on tree DBH, species, tree grades in different combinations and tree height. Results show that the tree grade variable increased the explained variation in product volumes. As expected, the accuracy of product volumes estimation, based on root mean square error (RMSE), was poor for an individual tree, but improved as the number of trees increased. [ABSTRACT FROM AUTHOR]

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ref.: Can. J. For. Res. 36: 945-952 (2006). The authors have discovered errors in the values presented in Table 1. The values for mortality and merchantable volume 34 years after [...]

Trees killed by natural disturbances have been recognized by the International Panel on Climate Change (IPCC) as a promising resource for bioenergy at the global scale. In the eastern boreal forest of Canada, there are two major types of natural disturbances that can generate large amounts of biomass for the production of bioenergy: wildfire and spruce budworm outbreak. For example, the mean burned area between 1970 and 2010 was estimated at 2900 km² per year. Following such disturbances, typically only trees and stands with a merchantable value, i.e., of acceptable quality for traditional forest products (lumberand pulp) are salvaged. However, adding bioenergy to the potential basket of productsmayboth divert trees of marginal quality and profitabilityaway fromtraditional products and to bioenergy facilities and lengthen the window of opportunity during which salvage operations can occur. This reviewshowshowthedynamics of wood characteristics of trees affected bynatural disturbancescanbe used to predict through time the basket of wood products that can be taken out of a salvaged stand and ensure the best fit between sources of fibre and types of processing facilities. The most important factors influencing fibre quality include degradation caused by fungi and insects. The mostsuitable time to salvage trees for the production of lumber in stands killed by either spruce budworm or fire is generally limited to 1-2 years after death. For the production of pulp and paper, trees can usually be salvaged for as long as the wood moisture content remains above the fibre saturation point, but usually is not recommended after 3 or 4 years following death. Thus, past this period, salvaged trees may yield better opportunities for the bioenergy sector. Information on wood as bioenergy feedstock (wood chips, wood pellets and liquid biofuel) highlights the importance of wood chemical components in the chemical reactivity of biofuel. This study offers background knowledge and a framework of analysis that highlights the potential of dead wood from natural disturbances for the production of forest and bioenergy products, whichcanbefurtheradaptedto other regions of theworld, buildingon the Canadian experience of adapting practices to natural disturbances. [ABSTRACT FROM AUTHOR]

Little attention has been given to changes in wood properties after isolated mortality events, which characterize the gap dynamics of several forest ecosystems. For the forest industry, dead and sound trees may represent a significant source of timber supply, but of potentially lower quality. The main objective of this study was therefore to compare the properties of wood obtained from dead and sound wood (DSW) trees with those from live trees. In total, 162 black spruce trees (Picea mariana (Mill.) BSP) were felled from three sites comprising three states of tree degradation and three diameter classes. In total, 822 pieces of lumber of different dimensions were produced and visually graded. Full-size lumber pieces of 4.3 –5.0 m in length (n = 343) were tested for wood stiffness and strength in longitudinal static bending. Samples of wood chips and bark were also collected during the production process at a sawmill. Results indicate that DSW trees produced lumber of significantly poorer mechanical properties than live trees. For the same modulus of elasticity (MOE) value, DSW trees have significantly lower modulus of rupture values than those of live trees, especially for MOE values of <15 GPa. This suggests that the wood of DSW trees is more brittle, a fact that should be taken into account for the production of machine-stress-rated lumber. Moisture content of wood chips was significantly lower in DSW trees, although it remained above the fibre saturation point. The amount of wood fibre attached to the bark was significantly higher in DSW trees. Considering these differences, DSW trees can be expected to provide wood of inferior quality than live trees but which still meet the technical requirements (Barrett and Lau, 1994) for producing structural lumber. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)