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Wood discoloration was investigated in 721 paper birch (Betula papyrifera Marsh.) trees from 146 sites across the managed forest of Quebec, Canada. Discoloration was present at breast height in 85% of trees, but its impact was limited in terms of tree basal area and volume, with proportions of 6.4% and 3.6%, respectively. These two measures were strongly correlated. Discoloration changed wood appearance but had no effect on microfibril angle and modulus of elasticity. Discolored wood was nevertheless denser, probably due to the accumulation of colored extractives. Predictive models were also developed and applied to 415 711 paper birch trees from 51689 inventory plots across the province to study regional variation. Higher proportions of discolored basal area were obtained in the southwestern areas of the province where the climate is warmer and drier. In these areas, paper birch trees are larger and, likely, support bigger branches which can cause larger columns of discoloration when broken. Lower proportions were found in eastern regions where snowfall is more abundant. Smaller, more flexible branches in trees growing in these areas could explain this result. This study confirms the feasibility of large-scale mapping of wood discoloration in standing trees based on forest inventory and climate data. Key words: paper birch, wood discoloration, wood properties, regional variation, climate. La coloration du bois a ete etudiee chez 721 tiges de bouleau blanc (Betula papyrifera Marsh.) provenant de 146 sites repartis a travers la foret amenagee du Quebec, au Canada. La coloration etait presente chez 85 % des arbres mais son impact etait faible : elle occupait seulement 6,4 % de la surface terriere et 3,6 % du volume des tiges. Ces deux variables etaient etroitement correlees. La coloration a modifie l'apparence du bois mais n'a eu aucun effet sur l'angle des microfibrilles ni sur le module d'elasticite. Le bois colore est neanmoins plus dense, vraisemblablement a cause de l'accumulation de matieres extractibles colorees. Des modeles de prediction ont egalement ete elabores et appliques a 415 711 tiges de bouleau blanc provenant de 51689 parcelles d'inventaire reparties a travers la province pour etudier la variation regionale. De plus grandes proportions de surface terriere de bois colore ont ete obtenues dans les regions du sud-ouest de la province oU le climat est plus chaud et plus sec. Dans ces regions, les tiges de bouleau blanc sont plus grosses et supportent probablement de plus grosses branches qui peuvent causer de plus grandes colonnes de coloration lorsqu'elles cassent. De plus faibles proportions de coloration ont ete trouvees dans les regions de l'est oU les chutes de neige sont plus abondantes. Le fait que les arbres croissant dans ces regions aient des branches plus petites et plus flexibles pourrait expliquer ce resultat. Cette etude confirme que la cartographie de la coloration a grande echelle dans les arbres sur pied est realisable a partir de donnees d'inventaire forestier et du climat. [Traduit par la Redaction] Mots-cles: bouleau blanc, coloration du bois, proprietes du bois, variation regionale, climat., Introduction Paper birch (Betula papyrifera Marsh.) is one of the most abundant hardwood species in Canada with a natural range from eastern to western coast (Safford et al. 1990). In [...]

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 [...]

There is a growing interest in using logging residues as feedstock in the bioeconomy. Quantifying the amount of this resource over large areas has been difficult due to the lack of availability of and consistency in forest inventory data across jurisdictions and the lack of a clear definition of what constitutes logging residues. The goal of this study was to develop an approach to spatially estimate the amounts of logging residues that would potentially be available in the near future for public lands across the Canadian managed forest using remote sensing maps and to compare these estimates with field assessments. Remote sensing estimates of branch and foliage biomass, although only a fraction of total postharvest residual biomass, were generally comparable with estimates from field assessments of recoverable residues after harvesting at the forest management unit (FMU) scale or at the 100 [km.sup.2] scale. However, they tended to not capture the strong variability between sites and to underestimate observed field values in regions that have very high biomass density. On average, the national logging residue density is estimated to be 26 [+ or -] 16 oven-dry tonnes (ODT) x [ha.sup.-1], and annual national availability is estimated to be 21 M ODT x [year.sup.-1]. Maps produced are available at doi:10.23687/dd94871a-9a20-47f5-825b-768518140f35 and doi:10.23687/5072c495-240c-42a3- ad55c942ab37c32a.Key words: logging residues, remote sensing, inventory, bioenergy, field assessment.L'utilisation des residus de coupe comme matiere premiere dans le secteur de la bioeconomie suscite de plus en plus d'interet. Il est difficile d'evaluer la quantite de cette ressource sur de vastes superficies a cause du manque de disponibilite et de consistance de donnees d'inventaire forestier a travers differentes juridictions et de l'absence d'une definition claire de ce qui constitue des residus de coupe. Cette etude visait a developper une approche pour estimer spatialement la quantite de residus de coupe potentiellement disponibles dans un proche avenir dans la foret amenagee du Canada sur terres publiques a l'aide de la cartographie par teledetection et de comparer ces estimations a des evaluations realisees sur le terrain. Les estimations de la biomasse des branches et du feuillage obtenues par teledetection, bien qu'elles ne representent qu' une fraction de la biomasse residuelle apres coupe, etaient generalement comparables aux evaluations des residus de coupe recuperables apres coupe realisees sur le terrain. Les estimations fondees sur la teledetection etaient en moyenne comparables aux valeurs obtenues sur le terrain a l'echelle de l'unite d'amenagement forestier ou a l'echelle de 100 [km.sup.2]. Par contre elles avaient tendance a ne pas detecter la forte variabilite entre les sites et a sous-estimer les valeurs observees sur le terrain dans les regions ou la densite de la biomasse est tres elevee. En moyenne, la densite des residus de coupe a l'echelle nationale est estimee a 26 [+ or - ] 16 tonnes anhydres (t.a.) x [ha.sup.-1] et la disponibilite nationale annuelle a 21 M t.a. x [an.sup.-1]. Les cartes qui ont ete produites sont disponibles sur doi:10.23687/dd94871a-9a20-47f5-825b-768518140f35 et doi:10.23687/5072c495-240c-42a3-ad55-c942ab37c32a. [Traduit par la Redaction]Mots-cles: residus de coupe, teledetection, inventaire, bioenergie, evaluation sur le terrain., IntroductionSecondary forest residues (i.e., processing or mill residues such as sawdust, shavings, and wood chips) are currently almost fully utilized in Canada (Natural Resources Canada 2006; Bradley 2008; Industrial Forestry [...]

Yield tables used for stand-level predictions of standing volume typically do not account for the presence of dead trees and stem decay. Yet, recently dead trees, referred to as dead and sound wood (DSW), could be considered as a valuable supplemental wood source. Conversely, stem decay can cause important losses during product recovery. Accordingly, the general objective of this study was to characterize the patterns of change of stem decay and of DSW as functions of time since the last fire (TSF). The amount of stem decay and of DSW per tree species were measured in two chronosequences of 30 stands each, covering more than 1000 years in the northeastern Canadian boreal forest. Stand-level decay volume increased during the first 150 years following fire and then stabilized. This volume was mainly composed of black spruce (Picea mariana (Mill.) BSP) when TSF < 200 years and of balsam fir (Abies balsamea (L.) Mill.) when TSF > 200 years. Conversely, the volume of DSW declined rapidly after fire and increased gradually from about 200 years TSF. Hence, the loss of wood volume attributable to stem decay in old-growth stands was cancelled out by the increased availability of DSW, with a slightly positive balance of 3.5 [m.sup.3]/ha. This could be significant considering the large amount of old-growth stands in this part of the boreal forest. Resume: Les tables de rendement utilisees pour predire le volume sur pied des peuplements ne tiennent pas compte de la presence des arbres morts ni de la carie du tronc. Pourtant, les arbres morts recemment, qu'on designera sous le nom de bois mort sain (BMS), pourraient etre consideres comme une source interessante de bois supplementaire. A l'inverse, la carie du tronc peut causer des pertes importantes lors de la transformation. Par consequent, l'objectif general de cette etude consistait a caracteriser l'evolution de la carie du tronc et du BMS en fonction du temps ecoule depuis le dernier feu de foret (TDF). Les quantites de carie du tronc et de BMS par espece d'arbre ont ete mesurees dans deux chronosequences comptant chacune 30 peuplements et couvrant plus de 1000 ans dans la foret boreale du nord-est du Canada. A l'echelle du peuplement, le volume de carie augmentait durant les premiers 150 ans apres un feu et se stabilisait par la suite. Ce volume etait surtout compose d'epinette noir (Picea mariana (Mill.) Britton, Sterns, Poggenb.) lorsque TDF etait < 200 ans et de sapin baumier (Abies balsamea (L.) Mill.) lorsque TDF etait > 200 ans. A l'inverse, le volume de BMS diminuait rapidement apres un feu et augmentait graduellement 200 ans environ apres un feu. Par consequent, la perte de volume de bois attribuable a la carie du tronc dans les vieux peuplements etait compensee par la disponibilite accrue de BMS, avec un bilan legerement positif de 3,5 [m.sup.3]/ha. Cela pourrait etre important etant donne la grande quantite de vieux peuplements dans cette partie de la foret boreale. [Traduit par la Redaction], Introduction Yield tables that are used by foresters to forecast future stand volume were originally conceived for even-aged stands (Vanclay 1994) to represent temporal changes in apparent live tree volume. [...]

Changing climates are altering the structural and functional components of forest ecosystems at an unprecedented rate. Simultaneously, we are seeing a diversification of public expectations on the broader sustainable use of forest resources beyond timber production. As a result, the science and art of silviculture needs to adapt to these changing realities. In this piece, we argue that silviculturists are gradually shifting from the application of empirically derived silvicultural scenarios to new sets of approaches, methods and practices, a process that calls for broadening our conception of silviculture as a scientific discipline. We propose a holistic view of silviculture revolving around three key themes: observe, anticipate and adapt. In observe, we present how recent advances in remote sensing now enable silviculturists to observe forest structural, compositional and functional attributes in near-real-time, which in turn facilitates the deployment of efficient, targeted silvicultural measures in practice that are adapted to rapidly changing constraints. In anticipate, we highlight the importance of developing state-of-the-art models designed to take into account the effects of changing environmental conditions on forest growth and dynamics. In adapt, we discuss the need to provide spatially explicit guidance for the implementation of adaptive silvicultural actions that are efficient, cost-effective and socially acceptable. We conclude by presenting key steps towards the development of new tools and practical knowledge that will ensure meeting societal demands in rapidly changing environmental conditions. We classify these actions into three main categories: re-examining existing silvicultural trials to identify key stand attributes associated with the resistance and resilience of forests to multiple stressors, developing technological workflows and infrastructures to allow for continuous forest inventory updating frameworks, and implementing bold, innovative silvicultural trials in consultation with the relevant communities where a range of adaptive silvicultural strategies are tested. In this holistic perspective, silviculture can be defined as the science of observing forest condition and anticipating its development to apply tending and regeneration treatments adapted to a multiplicity of desired outcomes in rapidly changing realities. [ABSTRACT FROM AUTHOR]

Baker's yeast suspensions with bacterial populations of 1,000,000 and 100,000,000 CFU/ml were subjected to autolysis processes for obtaining yeast extracts. Autolyses were performed at four different pH levels and with two autolysis-promoting agents. Decreases in the viable bacterial population after a 24-hr autolysis were seen when pH was adjusted to 4.0 or when ethyl acetate was introduced. A significant interaction was observed between the effects of pH and autolysis promoters on the bacterial population in yeast extracts, indicating that the activity of ethyl acetate, as opposed to that of chitosan, was not affected by pH.

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]

Unharvested hardwoods are abundant in eastern Canada, due to the low quality of their fiber and the absence of outlets in conventional wood transformation industries. The objective of this study was to assess the biochemical and thermochemical energy conversion potential of decaying hardwoods and compare their relationships with external and internal indicators of tree degradation. We characterized how wood-decay processes altered the physical and chemical properties of these woods and affected their digestibility yield and their performance according to indexes of stability and efficiency of combustion. DNA analysis on wood samples was also performed to determine the relative abundance of white-rot fungi compared to that of other saprotrophs. All properties stayed within the range of variations allowing the wood to remain suitable for conversion into bioenergy, even with increased decay. We found no significant differences in the physical and chemical properties that are crucial for energy production between wood from externally-assessed live and decayed trees. However, the proportion of wood area affected by rot was significantly associated with increased digestibility yield, and with decreased combustion reactivity. We could not detect any specific effect associated with increased relative abundance of white-rot fungi. These results suggest that the utilization of biomass from decayed hardwoods instead of live trees for bioenergy production should not alter the conversion efficiency and even potentially increase the performance of biochemical pathways, and hence, support their use as feedstock for bioenergy production. [ABSTRACT FROM AUTHOR]

Soon, physicians across Canada will be permitted to assist patients in dying, provided certain conditions are met. Physicians in the province of Quebec can already provide this service since December 10, 2015. While Quebec has been studying the question of legislating medical aid in dying since 2009, the rest of the country must come up with legislation on this issue within the next few months. This article suggests that other Canadian jurisdictions, federally and provincially/territorially, may find inspiration in the extensive work done in Quebec leading to its end-of-life legislation, including on the issues of identifying proper safeguards to protect vulnerable people and eligibility criteria that could be put in place in these jurisdictions. The Quebec model could be particularly useful in regard to the approach to balancing physicians' rights of conscience with patients' constitutional right to access medical aid in dying.