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Intra-annual density fluctuations (IADFs) are triggered by environmental cues, but whether they are distributed uniformly throughout the stem is not well documented. The spatial distribution of IADFs could help us understand variations in cambial sensitivity to environmental cues throughout the tree. We investigate how IADF distribution varies radially, longitudinally, and circumferentially within white pine (Pinus strobus L.) stems. We took wood samples at breast height, near branches, and at the top of the trees. We identified IADFs visually and measured their radial position within a ring as well as their circumferential arc in cross-sections. Intra-annual density fluctuations occurred in 22.2% of rings. The radial position of IADFs within a ring was remarkably consistent at roughly 80% of the total annual radial increment across heights, trees, and years of formation. The main factors affecting the likelihood of IADF occurrence were ring width, year of formation, and the interaction between the two. Being near branches or at the top of the tree slightly increased the probability of occurrence. Though the sample size was not large enough to provide conclusive results about the circumferential distribution of IADFs, our data suggest that the circumferential arc of the IADFs might be conserved throughout the stem. Key words: carbon, climate, false rings, IADFs, white pine, wood density, wood anatomy, wood formation, xylogenesis. Les fluctuations intra-annuelles de densite (FIAD) sont declenchees par des signaux environnementaux, mais leur distribution uniforme dans la tige n'est pas bien documentee. La distribution spatiale des FIAD pourrait aider les chercheurs a comprendre les variations de la sensibilite du cambium aux signaux environnementaux a travers l'arbre. Les auteurs examinent comment la distribution des FIAD varie radialement, longitudinalement et de maniere circonferentielle dans les tiges de pin blanc (Pinus strobus L.). Ils ont preleve des echantillons de bois a hauteur de poitrine, pres des branches et a la cime des arbres. Ils ont identifie visuellement les FIAD et mesure leur position radiale a l'interieur d'un anneau ainsi que leur arc circonferentiel dans les coupes transversales. Les FIAD etaient presentes dans 22,2 % des cernes. La position radiale des FIAD a l'interieur d'un anneau etait remarquablement constante a environ 80 % de l'increment radial annuel total a travers les hauteurs, les arbres et les annees de formation. Les principaux facteurs affectant la probabilite d'apparition de FIAD etaient la largeur du cerne, l'annee de formation et l'interaction entre les deux. Le fait d'etre pres des branches ou au sommet de l'arbre augmentait legerement la probabilite d'apparition. La taille de l'echantillon n'etait pas assez importante pour fournir des resultats concluants sur la distribution circonferentielle des FIAD, bien que les donnees suggerent que l'arc circonferentiel des FIAD pourrait etre conserve tout au long de la tige. [Traduit par la Redaction] Mots-cles: carbone, climat, faux cernes, FIAD, pin blanc, densite du bois, anatomie du bois, formation du bois, xylogenese., Introduction Annual wood growth rings, which are formed in seasonal climates, illustrate how wood formation varies inter- and intra-annually in trees. In temperate and boreal conifers, radial growth generally transitions [...]

Efforts to restore longleaf pine across the southeast United States have occurred on two distinct site types: cutover forests and old agricultural fields. We measured wood and bark physical properties of unthinned planted longleaf pine from 16 stands across Georgia, ages 12 to 25, with eight stands sampled from each site type. Three-hundred and twenty trees were felled and 3572 disks collected from within the trees. Wood and bark specific gravity (SG), moisture content (MC), and proportion of bark were measured. Non-linear mixed effects models were developed to predict the variation in wood and bark SG with respect to relative height, age, and site type. Cutover sites had higher whole-tree wood SG (0.504 vs 0.455) and bark SG (0.374 vs 0.347) than old agricultural fields. The models explained 50% and 37% of the variability in wood and bark SG, respectively. Moisture content models were fitted as a function of SG for wood ([R.sup.2] = 0.87) and bark ([R.sup.2] = 0.71). Bark thickness, dry mass, and green volume were higher for cutover forest sites. Trees sampled included both defect-free and defect-containing trees; however, no significant differences in the wood physical properties were found. These results provide important information for the utilization of plantation longleaf pine. Key words: longleaf pine plantation, Pinus palustris, southern pine, wood and fiber quality, wood density. Les efforts pour restaurer le pin des marais (Pinus palustris Mill.) a travers le sud-est des Etats-Unis ont ete deployes dans deux types de stations: des aires de coupes forestieres et de vieux champs agricoles. Nous avons mesure les proprietes physiques du bois et de l'ecorce de pins des marais non eclaircis provenant de 16 peuplements en Georgie et ages de 12 a 25 ans : huit peuplements ont ete echantillonnes dans chaque type de station. Trois cent vingt arbres ont ete abattus et 3572 disques ont ete preleves dans ces arbres. Le poids specifique (PS) et la teneur en humidite (TH) du bois et de l'ecorce ainsi que la proportion d'ecorce ont ete mesures. Des modeles non lineaires a effets mixtes ont ete elabores pour predire la variation du PS du bois et de l'ecorce en fonction de la hauteur relative, de l'age et du type de station. Le PS des arbres entiers et celui de l'ecorce etaient plus eleves dans les aires de coupes forestieres que dans les vieux champs agricoles, soit respectivement 0,504 contre 0,455 et 0,374 contre 0,347. Le modele expliquait respectivement 50 et 37 % de la variation du PS du bois et de l'ecorce. Les modeles de la teneur en humidite ont ete ajustes en tant que fonction du PS du bois ([R.sup.2] = 0,87) et de l'ecorce ([R.sup.2] = 0,71). L'epaisseur de l'ecorce, la masse anhydre et le volume a l'etat vert etaient plus eleves dans les aires de coupes forestieres. Les arbres echantillonnes incluaient aussi bien des arbres sans defauts qu'avec des defauts. Cependant, aucune difference significative n'a ete observee dans les proprietes physiques du bois. Ces resultats fournissent d'importantes informations pour l'utilisation des plantations de pin des marais. [Traduit par la Redaction] Mots-cles: plantation de pin des marais, Pinus palustris, pin du sud, qualite du bois et de la fibre, densite du bois., Introduction In the United States (US) and worldwide, southern pine is one of the most commercially important species groups, and it consists of longleaf pine (Pinus palustris Mill.), loblolly pine [...]

A common belief in forestry is that rapid growth in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) results in decreased outerwood quality. In Oregon, the opposite pattern has been reported for stands affected by Swiss needle cast, whereby a native fungus causes premature needle drop and an increase in latewood proportion (LW%), wood density, stiffness (MOE), and strength (MOR). Using a combination of new and existing data, we compared the properties of ~25-year-old outerwood from 18 healthy and 14 diseased stands using direct tests (6-8 beams from 7-12 trees per stand, 2614 beams total) and indirect SilviScanII tests (1 sample for each of the 366 trees). As seen before, diseased stands showed a decrease in wood quality with growth rate: ring count was strongly and positively correlated with density, MOE, and MOR ([r.sup.2] = 0.74, 0.65, and 0.63), and LW% was positively correlated with ring count, density, MOE, and MOR ([r.sup.2] = 0.50, 0.62, 0.30, and 0.44). In contrast, healthy stands showed no significant effect of ring count on density, MOE, or MOR. LW% was weakly and significantly correlated with MOE ([r.sup.2] = 0.25) but not with ring count, density, or MOR. Among healthy stands, growth acceleration had no adverse effects on outerwood properties. Key words: growth rate, modulus of elasticity, modulus of rupture, density, Swiss needle cast. Selon une croyance populaire la croissance rapide du douglas de Menzies typique (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) se solde par une deterioration de la qualite du bois mature. En Oregon, la tendance contraire a ete rapportee dans les peuplements infestes par la rouille suisse des aiguilles, ou un champignon indigene cause la chute prematuree des aiguilles et une augmentation de la proportion de bois final (%BF), de la densite, de la rigidite (MOE) et de la resistance (MOR) du bois. A l'aide d'une combinaison de donnees existantes et inedites, nous avons compare les proprietes du bois mature de tiges agees d'environ 25 ans provenant de peuplements sains (18) et malades (14) a l'aide de tests directs (6-8 eprouvettes prelevees sur 7-12 arbres par peuplement, soit au total 2614 eprouvettes) et de tests indirects effectues avec SilviScan II (un echantillon pour chacun des 366 arbres). Comme nous l'avions deja constate, la qualite du bois diminue avec le taux de croissance dans les peuplements malades : le decompte des cernes annuels etait etroitement et positivement correle avec la densite, MOE et MOR ([r.sup.2] = 0,74, 0,65 et 0,63) et le %BF etait positivement correle avec le decompte des cernes annuels, la densite, MOE et MOR ([r.sup.2] = 0,50, 0,62, 0,30 et 0,44). Par contre, dans les peuplements sains le decompte des cernes annuels n'a pas d'effet significatif sur la densite, MOE ou MOR. Le %BM etait faiblement mais significativement correle avec MOE ([r.sup.2] = 0,25) mais pas avec le decompte des cernes annuels, la densite ou MOR. Parmi les peuplements sains, l'acceleration de la croissance n'a pas d'effet negatif sur les proprietes du bois mature. [Traduit par la Redaction] Mots-cles: taux de croissance, module d'elasticite, module de rupture, densite, rouille suisse des aiguilles., Introduction Coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) is widely grown in plantations in its native range in western North America and across other parts of the world (Lavender [...]

We linked hydraulic vulnerability in Norway spruce (Picea abies (L.) Karst.) trunkwood with different cambial age to wood density and applied the findings on annual density variations in healthy and declining trees from southern Norway during 1990 to 2010. We hypothesized that drought stress due to the 2003 or 2006 European heat waves were the triggers for tree decline and focused analyses on the structure of wood that was produced after, as well as before, signs of stress, i.e., when decreases in height or diameter growth were visible. In the data set comprising previously published and new measurements, [P.sub.50], i.e., the pressure potential necessary to induce a 50% loss in hydraulic conductivity, was negatively related to wood density. Declining trees produced wider annual rings with lower density than vigorous trees before their radial and height increment started to decline in 2003 or 2006. Trees that produced low-density wood under favorable water availability were more stressed by a sudden drought event because of higher [P.sub.50] values in their sapwood. Due to the strong genotypic relationship between wood density and growth, we suggest that spruce trees selected for fast growth might experience limited hydraulic performance under the impact of extreme heat waves. Resume: Nous avons relie la vulnerabilite hydraulique dans le bois de tronc d'age cambial variable a la densite du bois chez l'epicea commun (Picea abies (L.) Karst.) et nous avons applique les resultats aux variations annuelles de densite dans des arbres sains et deperissants croissant dans le sud de la Norvege, de 1990 a 2010. Nous avons fait l'hypothese que le stress du a la secheresse causee par les vagues de chaleur de 2003 et 2006 en Europe avait declenche le deperissement des arbres et nous avons axe les analyses sur la structure du bois produit apres aussi bien qu'avant l'apparition des signes de stress, c.-a-d. lorsque la diminution de croissance en hauteur et en diametre est devenue visible. Dans le jeu de donnees compose de mesures deja publiees et de nouvelles mesures, [P.sub.50], c.-a-d. le potentiel hydrique qui entraine une perte de 50 % de la conductivite hydraulique, etait negativement relie a la densite du bois. Les arbres deperissants produisaient des cernes annuels plus larges avec une densite plus faible que les arbres vigoureux avant que leur accroissement radial et en hauteur commence a diminuer en 2003 ou 2006. Les arbres qui produisaient du bois de faible densite dans des conditions de disponibilite hydrique favorables etaient plus stresses par un episode soudain de secheresse parce que la valeur de [P.sub.50] dans leur bois d'aubier etait plus elevee. Etant donne l'etroite relation genotypique entre la densite du bois et la croissance, nous croyons que les epiceas selectionnes pour leur croissance rapide pourraient avoir une moins bonne performance hydraulique sous l'impact de vagues de chaleur extreme. [Traduit par la Redaction], Introduction Frequently occurring extreme weather events in the northern hemisphere such as the European heat waves of 2003 and 2006 (Intergovernmental Panel on Climate Change (IPCC) 2012) are a challenge [...]

Radial patterns of modulus of elasticity (MOE) were examined for white spruce (Picea glauca (Moench) Voss) and trembling aspen (Populus tremuoides Michx.) from 19 mature, uneven-aged stands in the boreal mixedwood region of northern Alberta, Canada. The main objectives were to (1) evaluate the relationship between pith-to-bark changes in MOE and cambial age or distance from pith; (2) develop species-specific models to predict pith-to-bark changes in MOE; and (3) to test the influences of radial growth, relative vertical height, and tree slenderness (tree height/DBH) on MOE. For both species, cambial age was selected as the best explanatory variable with which to build pith-to-bark models of MOE. For white spruce and trembling aspen, the final nonlinear mixed-effect models indicated that an augmented rate of increase in MOE occurred with increasing vertical position within the tree. For white spruce trees, radial growth and slenderness were found to positively influence maximum estimated MOE. For trembling aspen, there was no apparent effect of vertical position or radial growth on maximum MOE. The results shed light on potential drivers of radial patterns of MOE and will be useful in guiding silvicultural prescriptions. Resume: Le profil radial du module d'elasticite (MOE) a ete etudie chez l'epicea blanc (Picea glauca (Moench) Voss) et le peuplier faux-tremble (Populus tremuloides Michx.) a partir de 19 peuplements inequiennes matures situes dans la foret boreale mixte du nord de l'Alberta, au Canada. Les principaux objectifs consistaient a (1) evaluer la relation entre la variation du MOE de la moelle a l'ecorce et l'age cambial ou la distance de la moelle; (2) developper des modeles propres a chaque espece pour predire la variation radiale du MOE; et (3) tester l'influence de la croissance radiale, de la hauteur relative et de l'elancement (hauteur de l'arbre/DHP) de l'arbre sur le MOE. Chez les deux especes, l'age cambial a ete retenu en tant que meilleure variable explicative dans les modeles du MOE de la moelle a l'ecorce. Chez l'epicea blanc et le peuplier faux-tremble, le modele final non lineaire a effets mixtes indiquait que le taux d'augmentation du MOE etait plus rapide a mesure que la position verticale dans l'arbre etait plus elevee. Dans le cas des tiges d'epicea blanc, la croissance radiale et l'elancement exercent une influence positive sur le MOE estime maximum. Dans le cas du peuplier faux-tremble, la position verticale ou la croissance radiale n'ont aucun effet apparent sur le MOE maximum. Les resultats nous renseignent sur les facteurs potentiellement responsables du profil radial du MOE et seront utiles pour orienter les prescriptions sylvicoles. [Traduit par la Redaction], Introduction Modulus of elasticity (MOE), defined here as a measure of stiffness, is an important wood property whose radial pattern of maturation in trees has been shown to vary across [...]

This study focused on wood density and annual ring width in Norway spruce (Picea abies (L.) Karst.) grown in uneven-aged stands (UAS). In total, 96 trees were harvested from five UAS that had been managed by single-tree selection for decades. A data set of 27 trees from even-aged stands (EAS) was used for comparison. In the UAS trees, high density and narrow annual rings were found in the juvenile wood near the pith. Thereafter, wood density rapidly decreased until the 20th annual ring, followed by an increase toward the bark. In the outermost rings, wood density again slightly decreased. The trends in wood density in the UAS trees correspond with those reported for naturally regenerated, even-aged Norway spruce stands, with the exception of the decrease in the outermost rings. A mixed linear model with ring width, cambial age, and canopy position as fixed parameters accounted for 53% of the variation in wood deensity of the UAS trees. In contrast to UAS trees, EAS trees showed increased wood density in the outer rings as a result of decreasing growth rate. The abrupt change in wood density of UAS trees may affect the properties of timber sawn close to the pith. Resume: Cette etude s'interesse a la densite du bois et a la largeur des cernes annuels de l'epicea commun (Picea abies (L.) Karst.) qui croit en peuplement inequienne (PI). Au total, 96 arbres ont ete recoltes dans cinq PI traites par la methode de jardinage par arbre depuis des decennies. Un ensemble de donnees comprenant 27 arbres provenant de peuplements equiennes (PE) a ete utilise a des fins de comparaison. Dans les arbres des PI, la densite du bois etait elevee et les cernes annuels etaient etroits dans le bois juvenile pres de la moelle. Ensuite, la densite du bois diminuait rapidement jusqu'au [20.sup.e] cerne annuel suivie d'une augmentation en allant vers l'ecorce. La densite du bois diminuait encore legerement dans les cernes les plus recents. Le profil de la densite du bois dans les arbres des PI correspondait a celui qui a ete rapporte pour les PE d'epicea commun naturellement regeneres, a l'exception de la diminution dans les cernes les plus recents. Un modele lineaire mixte ayant comme variables independantes la largeur du cerne, l'age cambial et la position dans le couvert forestier expliquait 53 % de la variation de la densite du bois dans les arbres des PI. Dans les arbres des PE, contrairement a ceux des PI, la densite du bois augmentait dans les cernes les plus recents a cause de la diminution du taux de croissance. Le changement abrupt dans la densite du bois des arbres des PI peut avoir un impact sur les proprietes du bois scie pres de la moelle. [Traduit par la Redaction], 1. Introduction In European and Nordic countries, Norway spruce (Picea abies (L.) Karst.) is mainly grown in even-aged stands. Since 1948, uneven-aged silviculture and selection cuttings have been prohibited in [...]

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 [...]

: The wood quality of maritime pine (Pinus pinaster Ait.) is discussed in view of spatial variability of density, annual growth ring charact[E.sub.R]istics, and transverse elastic properties within and among five basal logs. X-ray microdensitometry measurements are carried out to assess both average ([D.sub.mean]) and local ([D.sub.EW], [D.sub.LW]) densities of annual growth rings, as well as the respective dimensions (E[W.sub.W], L[W.sub.W]) and fractions of earlywood (EW) and latewood (LW) layers. Mechanical tensile tests on a set of specimens with different ring orientation are proposed. Transverse elastic properties are determined by coupling an inverse identification strategy with full-field deformation measurements provided by digital image correlation. For a suitable range of off-axis angles, this method allows the simultaneous characterisation of the four orthotropic elastic properties in the RT plane: [E.sub.R], [E.sub.T], +[v.sub.RT], and [G.sub.RT]. These results are found in agreement with reference values. From the sampled specimens among logs, [E.sub.R] and [G.sub.RT] are robustly identified in all cases and therefore are selected for further analysis of structure-properties relationships. Correlations between [D.sub.mean] and [E.sub.R] and [G.sub.RT] are positive and statistically significant. Furthermore, other parameters also show significant correlations with the elastic constants, especially [D.sub.min], L[W.sub.W], and [D.sub.EW]. Key words: digital image correlation, mat[E.sub.R]ial parameter identification, mechanical testing, wood, X-ray microdensitometry. Resume: Il est question dans cet article de la qualite du bois du pin maritime (Pinus pinaster Ait.) a la lumiere de la variabilite de la densite, des caracteristiques des cernes annuels et des proprietes elastiques transverses dans et entre cinq billes de pied. Des mesures de microdensitometrie aux rayons x ont ete effectuees pour evaluer la densite locale ([D.sub.EW] et [D.sub.LW]) et moyenne ([D.sub.mean]) des cernes annuels ainsi que la dimension respective (E[W.sub.W], L[W.sub.W]) et la proportion de bois initial (EW) et de bois final (LW). On present des essais mecaniques de traction sur un groupe de specimens avec differentes orientations des cernes. Les proprietes elastiques transverses ont ete determinees en couplant une strategie inverse d'identification et des mesures de deformation totale fournies par la correlation d'images digitales. Pour une gamme appropriee d'angles hors axe, cette methode permet de caracteriser simultanement les quatre proprietes elastiques orthotropiques dans le plan RT: [E.sub.R], [E.sub.T], + [v.sub.RT] et [G.sub.RT]. Ces resultats correspondent aux valeurs de reference. A partir des specimens echantillonnes parmi les billes, [E.sub.R] et [G.sub.RT] ont ete identifies avec certitude dans tous les cas et ont par consequent ete choisis pour une analyse plus poussee des relations entre la structure et les proprietes. Les correlations entre [D.sub.mean] et [E.sub.R] et [G.sub.RT] sont positives et statistiquement significatives. De plus, d'autres parametres sont aussi significativement correles avec les constantes elastiques, plus particulierement [D.sub.mean], L[W.sub.W], et [D.sub.EW]. [Traduit par la Redaction] Motscles: correlation d'images digitales, identification des parametres de materiau, essais mecaniques, bois, microdensitometrie aux rayons x., 1. Introduction In a policy environment of green economy and sustainable development, wood and wood-based products have been increasingly used for structural applications. However, for competitiveness purposes with regard to [...]

Knowledge about the wood quality of standing trees is crucial in that it serves as an excellent means for nearly all stages of the wood-supply chain. Better information about internal wood characteristics can be derived from the outside appearance by establishing a correlation between the bark characteristics of a stem and its internal quality. This paper presents an approach where the quality determination of standing trees using a terrestrial light detection and ranging (LiDAR) system is combined with the information about internal quality of logs using X-ray computed tomography (CT). Results show a high accuracy for branch scar measurements with terrestrial LiDAR and knot measurement with CT. A strong correlation between scar seal quotient and the amount of clear wood could be confirmed using European beech (Fagus sylvatica L.) as an example. Quality grading of virtually segmented logs using terrestrial LiDAR and CT showed moderate correlation; 62.5% of the segments were allocated to the same grade by both approaches. In conclusion, terrestrial LiDAR in forest inventory could be used as an instrument to predict inner wood quality in greater detail by gathering data on the outer appearance and branch scars of standing trees. This additional knowledge has the potential to improve forest planning, bucking instructions, and a roundwood allocation that meets industry demand. Resume : Il est essentiel de connaitre la qualite du bois des arbres sur pied car cela est d'une grande utilite a presque toutes les etapes de la chaine d'approvisionnement en bois. Une meilleure information au sujet des caracteristiques internes du bois peut etre derivee de l'apparence externe en etablissant une correlation entre les caracteristiques de l'ecorce d'une tige et sa qualite interne. Cet article presente une approche qui consiste a determiner la qualite des arbres sur pied a l'aide d'un systeme lidar terrestre (detection et telemetrie par la lumiere) combine a des informations sur la qualite interne des billes obtenues grace a la tomodensitometrie aux rayons X (CT). Les resultats montrent la grande precision des mesures de cicatrice de branche avec le lidar terrestre et de celles des nreuds avec le CT. Une etroite correlation entre le rapport hauteur/largeur des cicatrices de branche et la quantite de bois sain a pu etre confirmee en utilisant le hetre commun (Fagus sylvatica L.) comme exemple. Les classements par qualites des billes virtuellement segmentees a l'aide du lidar terrestre et du CT etaient moderement correles : 62,5 % des segments ont ete attribues a la meme classe par les deux approches. En conclusion, le lidar terrestre pourrait etre utilise dans les inventaires forestiers pour predire la qualite interne du bois de facon plus detaillee en recoltant des donnees sur l'apparence externe et les cicatrices de branche des arbres sur pied. Cette information additionnelle pourrait ameliorer la planification forestiere, les instructions de tronconnage et l'allocation des bois ronds en fonction des specifications de l'industrie. [Traduit par la Redaction], Introduction One major quality feature of sawlogs is the ratio between knotty core and clear wood. After trees are naturally or artificially pruned, knots become occluded and clear wood is [...]

The trend towards shorter rotations in planted conifer stands has resulted in a reduction in the proportion of mature wood relative to juvenile core wood, raising concerns that the mechanical performance of sawn battens will be affected. The potential to improve the wood quality of the juvenile core of Sitka spruce (Picea sitchensis (Bong.) Carriere) without compromising growth rate was investigated. Rapid and inexpensive indirect methods of assessing wood properties on standing trees using a Pilodyn gun and acoustic velocity were compared with direct measurements made on wood samples cut from the juvenile core. Strong genetic correlations were observed between Pilodyn gun values and direct measures of density (-0.76) and between the square of acoustic velocity and modulus of elasticity (0.73). The genetic correlation between the square of acoustic velocity and microfibril angle was also strong (-0.84). These results suggest that indirect assessments of wood properties within juvenile core wood are sufficiently reliable for these techniques to be used in the Sitka spruce breeding programme. Although a strong negative genetic correlation between diameter at breast height and density was noted (-0.79), sufficient variation exists within the breeding population to select families with both good growth rate and high modulus of elasticity wood. Resume: La tendance a raccourcir la periode rotation dans les plantations de coniferes a entra?ne une reduction de la proportion de bois de caeur mature relativement au bois de caeur juvenile. Cette situation fait craindre que la performance mecanique des tasseaux scies soit affectee. La possibilite d'ameliorer la qualite du bois de caeur juvenile de l'epicea de Sitka (Picea sitchensis (Bong.) Carriere), sans compromettre le taux de croissance, a ete etudiee. Des methodes indirectes, rapides et peu couteuses, pour evaluer les proprietes du bois dans les arbres sur pied a l'aide du pilodyn et de la vitesse sonique ont ete comparees a des mesures directes sur des echantillons de bois de caeur juvenile. D'etroites correlations genetiques ont ete observees entre les valeurs du pilodyn et les mesures directes de densite (-0,76) et entre la vitesse sonique au carre et le module d'elasticite 0,73). La correlation genetique entre la vitesse sonique au carre et l'angle des microfibrilles etait egalement etroite (-0,84). Ces resultats indiquent que l'evaluation indirecte des proprietes du bois dans le bois de caeur juvenile est suffisamment fiable pour que ces techniques soient utilisees dans le programme d'amelioration de l'epicea de Sitka. Bien qu'une etroite correlation genetique negative (-0,79) ait ete notee entre le diametre a hauteur de poitrine et la densite, il existe suffisamment de variation dans la population en selection pour selectionner des descendances qui ont un bon taux de croissance et dont le bois a un module d'elasticite eleve. [Traduit par la Redaction], Introduction There are 700 000 ha of Sitka spruce (Picea sitchensis (Bong.) Carriere) 'plantation' forest in Britain and around 32 million Sitka spruce trees are planted annually, representing a major [...]

Magnetic resonance spectroscopy and imaging are well established analytical tools with ever-increasing ranges of application. They are, however, generally underutilized in the areas of forestry and wood science. This is in part due to the complex nature of wood and wood-water interactions and also to the need of wood scientists for quantitative measurements of moisture content, fluid flow, wood structure, etc. Furthermore, magnetic resonance instruments have historically been large, sophisticated, and expensive and not generally compatible with wood production facilities. In this paper, we discuss the limitations of magnetic resonance to applications such as wood and describe how, with recent developments in magnetic resonance imaging technology, these limitations can be overcome. We highlight our own work with quantitative moisture content measurements and outline progress in the development of simpler, lightweight, and mobile magnetic resonance instruments. These are promising devices for routine portable magnetic resonance spectroscopy and imaging, with the potential to finally extend these powerful techniques to the world of foresters and wood scientists. La spectroscopie et l'imagerie par resonnance magnetique sont des outils analytiques bien etablis dont le champ d'application s'elargit sans cesse. Cependant, ils sont generalement sous-utilises dans les domaines de la foresterie et des sciences du bois. Cela est du en partie a la nature complexe du bois et aux interactions entre le bois et l'eau, ainsi qu'a la necessite pour les scientifiques du bois d'obtenir des mesures quantitatives de la teneur en humidite, du mouvement des fluides, de la structure du bois, etc. De plus, les appareils de resonnance magnetique ont historiquement ete volumineux, sophistiques, dispendieux et generalement incompatibles avec les installations de production du bois. Dans cet article, nous discutons des limites de la resonnance magnetique pour des applications telles que le bois et nous decrivons comment, avec les recents developpements des techniques d'imagerie par resonnance magnetique, on peut surmonter ces difficultes. Nous mettons en evidence nos propres travaux sur la mesure quantitative de la teneur en humidite et nous decrivons les progres dans le developpement d'appareils de resonnance magnetique plus simples, legers et mobiles. Ce sont des appareils prometteurs pour l'utilisation routiniere et portative de la spectroscopie et de l'imagerie par resonnance magnetique qui pourraient finalement etendre l'utilisation de ces puissantes techniques au monde des forestiers et des scientifiques du bois. [Traduit par la Redaction], Introduction In Canada and around the world, forestry and forest products are large and vital industries. The number and sophistication of analytical techniques available to scientists and engineers to characterize [...]

An in-depth understanding of the response of wood under compression/densification calls for characterization of strain distribution over the wood. Recently, an image processing technique has been used for strain evaluation on wood, as the traditional devices are not able to measure irregularly distributed strain field. Unfortunately, the classic image correlation algorithm is rather time consuming and could take up to days to compute the final result. In this paper, an improved image correlation algorithm with linearly changed searching region during the correlation seeking is presented. The processing speed is increased by over 1800 times while keeping the high accuracy of the displacement measurement. In addition, full feasibility tests were conducted on balsam fir (Abies balsamea (L.) Mill.) and eastern white pine (Pinus strobus L.) samples.The results demonstrate the high robustness, efficiency, and accuracy of the proposed method. Une connaissance approfondie de la reaction du bois soumis a la compression ou a la densification exige la carac-terisation de la distribution des tensions dans le bois. La technique de traitement des images a recemment ete utilisee pour evaluer les tensions dans le bois etant donne que les appareils traditionnels ne sont pas capables de mesurer un champ de tension distribue de facon irreguliere. Malheureusement, l'algorithme classique de correlation des images demande passable-ment de temps et pourrait prendre plusieurs jours pour calculer le resultat final. Dans cet article, nous presentons un algo-rithme de correlation d'images ameliore avec une zone de recherche lineairement modifiee pendant la recherche de correlations. La vitesse de traitement est 1 800 fois plus rapide tout en conservant la precision elevee de la mesure des de-placements. De plus, des tests complets de faisabilite ont ete realises sur des echantillons de sapin baumier (Abies balsamea (L.) Mill.) et de pin blanc (Pinus strobus L.). Les resultats demontrent que la methode proposee est tres robuste, efficace et precise. [Traduit par la Redaction], Introduction Recently, wood densification has attracted the attention of researchers (Wang and Cooper 2005; Gong et al. 2006). This technology allows utilization in new applications of wood from some fast-growing [...]

In several processes of the forest products industry, an in-depth knowledge of log and board internal features is required and their determination needs fast scanning systems. One of the possible technologies is X-ray computed tomography (CT) technology. Our paper reviews applications of this technology in wood density measurements, in wood moisture content monitoring, and in locating internal log features that include pith, sapwood, heartwood, knots, and other defects. Annual growth ring measurements are more problematic to be detected on CT images because of the low spatial resolution of the images used. For log feature identification, our review shows that the feed-forward back-propagation artificial neural net-work is the most efficient CT image processing method. There are also some studies attempting to reconstruct three-dimensional log or board images from two-dimensional CT images. Several industrial prototypes have been developed because medical CT scanners were shown to be inappropriate for the wood industry. Because of the high cost of X-ray CT scanner equipment, other types of inexpensive sensors should also be investigated, such as electric resistivity tomography and micro-waves. It also appears that the best approach uses various different sensors, each of them having its own strengths and weak-nesses. Plusieurs processus de l'industrie des produits forestiers exigent une connaissance approfondie des caracteristiques internes des billes et des planches dont l'acquisition necessite des appareils a balayage rapide. Une des technologies potentielles est la tomodensitometrie (TDM). Notre article passe en revue les applications de cette technologie pour mesurer la densite du bois, faire le suivi de la teneur en humidite dans le bois et localiser les caracteristiques internes du bois, telles que la moelle, le bois d'aubier, le bois de coeur, les noeuds et les autres defauts. Il est plus difficile de mesurer les cernes annuels sur les images obtenues par TDM a cause de la faible resolution spatiale de ces images. Pour l'identification des caracteristiques des billes, notre revue montre que le reseau neuronal artificiel multicouche a retropropagation est la methode la plus efficace pour traiter les images obtenues par TDM. Il y a aussi certaines etudes qui tentent de reconstruire des images en trois dimensions a partir des images en deux dimensions obtenues par TDM. Plusieurs prototypes industriels ont ete developpes parce qu'il a ete demontre que les tomographes medicaux ne sont pas appropries pour l'industrie du bois. Etant donne le cout eleve des appareils de TDM, d'autres types de capteurs bon marche devraient etre etudies, tels que la tomo-graphie de resistivite electrique et les micro-ondes. Il semble aussi que la meilleure approche consiste a utiliser plusieurs capteurs differents, chacun ayant ses forces et ses faiblesses. [Traduit par la Redaction], Introduction In current wood manufacturing operations, knowledge of wood characteristics and measurement of those characteristics are essential to ensure that the right fibre is directed to the appropriate wood manufacturing [...]

Red heartwood, a dark nonhomogenous discolouration in paper birch trees (Betula papyrifera Marsh.), limits the applications and uses of sawn boards to nonvisible low-value products, thus resulting in substantial value loss. The occurrence and distribution of red heartwood were investigated in 12 paper birch trees grown in the province of Quebec, Canada. The youngest tree was 62 years old at breast height and the oldest 86 years old for an average of 75 years old. In this study, 225 occurrences of external traits, relating to branch scars and forks, previously proposed as initiation points for red heartwood were identified and measured. The distribution of red heartwood was digitally mapped and the effect of these external traits on the red heartwood surface and shape inside each tree was examined. Results show that red heartwood initiates from an external trait and that multiple external traits can contribute to the development of a red heartwood column following the longitudinal axis of the stem. Red heartwood appeared to initiate mainly from external traits at the base of the tree. A modelling exercise indicated that the width of the red heartwood column inside a standing tree can be estimated from branch scar width and height from the ground. Tree vigour could not be linked to the proportion of red heartwood inside standing trees. A three-dimensional analysis of log shape could potentially be used to detect red heartwood presence in a log before processing to optimize the log sawing pattern. Resume: Le coeur rouge, une coloration foncee irreguliere du bois presente chez certains bouleaux blancs (Betula papyrifera Marsh.), limite les applications et les usages du bois scies a des produits non visibles de faible valeur, ce qui entraine une perte de valeur substantielle. La presence et la distribution du coeur rouge ont ete etudiees chez 12 bouleaux blancs croissant dans la province de Quebec, au Canada. L'arbre le plus jeune avait 62 ans a hauteur de poitrine et le plus vieux avait 86 ans; la moyenne d'age etait de 75 ans. Dans cette etude, 225 defauts externes relies a des cicatrices de branche et a des fourches, precedemment consideres comme points d'origine du coeur rouge, ont ete identifies et mesures. La distribution du coeur rouge a ete cartographiee numeriquement et l'effet de ces defauts externes sur la surface et la forme du coeur rouge a ete examine dans chaque arbre. Les resultats montrent que le coeur rouge est initie a partir d'un defaut externe et que plusieurs defauts externes peuvent contribuer au developpement d'une colonne de bois de coeur rouge le long de l'axe longitudinal de la tige. Le coeur rouge semblait etre initie surtout a partir de defauts externes situes a la base de la tige. Un exercice de modelisation a indique que la largeur de la colonne de bois de coeur rouge a l'interieur d'un arbre sur pied peut etre estimee a partir de la largeur des cicatrices de branche et de leur hauteur a partir du sol. La vigueur de l'arbre ne pouvait etre reliee a la proportion de bois de coeur rouge a l'interieur d'un arbre sur pied. Une analyse tridimensionnelle de la forme des billes pourrait possiblement etre utilisee pour detecter la presence du coeur rouge dans une bille avant d'etre transformee afin d'optimiser le schema de debit de la bille. [Traduit par la Redaction], Introduction Physical and visual characteristics influence both the value and utilization of wood in appearance products such as furniture and wood flooring. Among these characteristics, wood colour is a determinant [...]

Detailed radial measurements of wood properties at four heights (0, 1.4, 5, and 20 m) were taken from 24-year-old Pinus radiata D. Don growing at four final crop stockings (200, 350, 500, and 1100 [stems * ha.sup.-1]). Using these measurements, the objectives of the study were to examine pith-to-bark trends at several heights to (i) determine how stocking influenced modulus of elasticity (MoE), wood density, and microfibril angle (MFA), (ii) quantify the relations among these properties and age at different stocking levels, and (iii) develop a graphical model for MoE across the stocking range. The influence of stocking on all wood properties was primarily expressed through a highly significant interaction between age and stocking. Wood properties in the highest stocking treatment diverged from those in the lowest stocking treatment at tree age 5 to reach a maximum difference of 92 [kg * m.sup.-3] (488 vs. 580 [kg * m.sup.-3]) at tree age 18 for density, -5.7° (29.2° vs. 23.5°) at tree age 10 for MFA, and 5.1 GPa (12.1 vs. 17.2 GPa) at tree age 20 years for MoE. Graphical predictions from the model show greatest gains in MoE at high final crop stocking to occur over the lower part of the stem. Resume: Des mesures detaillees des proprietes du bois en direction radiale ont ete prises a quatre hauteurs (0, 1,4, 5 et 20 m) sur des tiges de Pinus radiata D. Don agees de 24 ans et qui croissaient en peuplement final, avec differentes densites relatives (200, 350, 500 et 1100 tiges * ha-1). a partir de ces mesures, les objectifs de cette etude consistaient a etudier les tendances de la moelle a l'ecorce a plusieurs hauteurs pour (i) determiner l'effet que la densite relative a sur le module d'elasticite (MOE), la densite du bois et l'angle des microfibrilles (AMF), (ii) quantifier les relations entre ces proprietes et l'age a differents niveaux de densite relative et (iii) elaborer un mod * le graphique du MOE pour toute la gamme de densite relative. L'influence de la densite relative sur toutes les proprietes du bois se manifestait principalement par une interaction tr * s significative entre l'age et la densite relative. Les proprietes du bois associees au traitement avec la plus forte densite relative etaient differentes de celles qui etaient associees au traitement avec la plus faible densite relative d * s l'age de 5 ans et la difference atteignait un maximum de 92 kg * m-3 (488 vs. 580 kg * m-3) a l'age de 18 ans pour la densite du bois, de -5,7° (29,2° vs. 23,5°) a l'age de 10 ans pour l'AMF et de 5,1 GPa (12,1 vs. 17,2 GPa) a l'age de 20 ans pour le MOE. Les predictions du mod * le graphique indiquent que les plus fortes augmentations du MOE dans le peuplement avec la densite relative la plus elevee se produisent dans la partie inferieure de la tige., Introduction Advances in tree breeding and changes in silvicultural practice over the last few decades have greatly enhanced growth rates of plantation-grown conifers. These growth gains have led to shorter [...]

The wood of Quercus faginea Lam. was studied regarding its density variation within and between trees using microdensitometry techniques in 10 trees growing in northern Portugal. The observations were made in mature trees at several height levels (stem base and 1.3, 3.4, 5.5, 7.6, and 9.7 m). Variance analysis was done considering the core cylinder (first 15 rings) and the sheath (last 10 rings) in relation to tree, height level, and ring effects and their interactions. The wood revealed a high mean density of 0.848 g * [cm.sup.-3]with small differences between earlywood and latewood (0.717 and 0.908 g * [cm.sup.-3], respectively). Latewood corresponded on average to 66% of the total ring width, which averaged 2.4 mm. Wood density decreased with height and radially from pith to cambium. However, within-tree variation was of very moderate magnitude although higher for juvenile wood. Variation between trees was also small (6% coefficient of variation of the mean) and higher for the mature wood. Quercus faginea wood compares favourably with other oak species with regard to density characteristics and may be considered for production of quality solid wood products. La variation de la densite du bois du Quercus faginea Lam., dans et entre les arbres, a ete etudiee a l'aide des techniques de microdensitometrie chez 10 arbres croissant dans le nord du Portugal. Les observations ont ete faites sur des arbres matures a plusieurs hauteurs (base du tronc et 1,3, 3,4, 5,5, 7,6 et 9,7 m). L'analyse de variance a porte sur le cylin-dre central (premiers 15 cernes) et l'enveloppe externe (derniers 10 cernes) en lien avec les effets de l'arbre, de la hauteur et des cernes ainsi que leurs interactions. La densite moyenne du bois etait elevee (0,848 g * [cm.sup.-3]) et la difference entre le bois initial et le bois final (respectivement 0,717 et 0,908 g * [cm.sup.-3]) etait faible. Le bois final representait en moyenne 66 % de la largeur totale des cernes annuels qui atteignait en moyenne 2,4 mm. La densite du bois diminuait avec la hauteur et radia-lement du coeur vers le cambium. Cependant, l'ampleur de la variation intra-arbre etait moderee quoique plus forte dans le bois juvenile. La variation entre les arbres etait egalement faible (coefficient de variation de la moyenne de 6 %) et plus forte pour le bois mature. Le bois du Q. faginea se compare favorablement avec celui des autres especes de chene quant aux caracteristiques de la densite et peut etre retenu pour la production de produits en bois massif. [Traduit par la Redaction], Introduction The Portuguese oak (Quercus faginea Lam.) is native to Portugal and Spain, abundant in former times, but now limited to a few thousand hectares (Capelo and Catry 2007). The [...]

Because stiffness (modulus of elasticity (MOE)) is important for structural wood products, breeders and silviculturists seek to efficiently measure and improve this trait. We studied MOE in a 25-year-old progeny test of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) using field-based tools (ST300 and HM200) to measure stress wave MOE of standing trees and logs. We measured density, static bending MOE, and transverse vibration MOE on 2 x 4s, and density, SilviScan MOE, and SilviScan microfibril angle on small clearwood samples. Bending MOE had moderate to strong phenotypic and genetic correlations with stress wave MOE of trees and logs, transverse vibration MOE of 2 x 4s, and the densities of 2 x 4s and basal wood discs but was weakly correlated with the numbers and sizes of knots. The best lumber grade had the highest bending stiffness and smallest edge knots. Bending stiffness had a strong positive correlation with the density of small clearwood samples and a moderate negative correlation with microfibril angle. Compared with microfibril angle and edge knots, path analyses indicated that density had the strongest direct effect on bending MOE. We recommend that breeders measure and select for stress wave velocity to improve bending stiffness in Douglas-fir. Genetic gains can be increased by including wood density, but genetic selection for fewer or smaller knots will be ineffective. En raison de son importance pour les produits structuraux, les geneticiens et les sylviculteurs cherchent a ameliorer la rigidite du bois (module d'elasticite (MOE)) et a la mesurer de facon efficace. A l'aide de mesures (ST300 et HM200) du MOE par onde de contrainte prises sur le terrain, nous avons etudie le MOE d'arbres sur pied et de billes provenant d'un test de descendance de douglas de Menzies (Pseudotsuga menziesii (Mirb.) Franco) age de 25 ans. Nous avons mesure la densite, le MOE en flexion statique et le MOE en vibration transverse sur des 2 x 4 ainsi que la densite, le MOE SilviScan et l'angle des microfibrilles SilviScan sur de petites eprouvettes de bois sans defauts. Le MOE en flexion avait des correlations ph enotypiques et genetiques allant de moderees a fortes avec le MOE mesure par onde de contrainte des arbres et des billes, le MOE en vibration transverse des 2 x 4 et la densit e des 2 x 4 et des rondelles de bois a la base mais il etait faiblement correle avec le nombre et la taille des noeuds. La meilleure qualite de bois scie avait la plus grande rigidit e en flexion et les plus petits noeuds de rive. La rigidite en flexion avait une forte correlation positive avec la densite des petites eprouvettes de bois sans d efauts et une correlation n egative moderee avec l'angle des microfibrilles. Comparativement a l'angle des microfibrilles et aux noeuds de rive, les analyses des pistes causales ont indique que la densite avait le plus grand effet direct sur le MOE en flexion. Nous recommandons que les geneticiens mesurent la vitesse de propagation d'une onde de contrainte et selectionnent sur cette base afin d'am eliorer le MOE en flexion du douglas de Menzies. Les gains g en etiques peuvent etre ameliores en incluant la densite du bois, mais une selection genetique pour un moins grand nombre ou de plus petits noeuds sera inefficace. [Traduit par la Redaction], Introduction Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is the principal lumber species in the Pacific Northwest because it is widely distributed, grows quickly, and has excellent wood quality. Douglas-fir is widely [...]

* Premise of the study: The density of wood is highly correlated with the ability of stems and roots to resist bending or twisting, which is important for evaluating the mechanical behavior of trees. It also provides a measure of carbon storage, which is an important variable in modeling ecosystem processes and tree construction costs. However, most measurements of the density and mechanical properties of wood have little direct bearing on understanding the biomechanics of living plants because they are based on kiln- or air-dried samples. * Methods: Here, we present and analyze the relationships between four important mechanical properties (Young's modulus, the modulus of rupture, and the maximum strength in shearing and in compression) and the density of green wood (i.e., wood at 50% moisture content) from a worldwide, taxonomically broad spectrum of 161 species. * Key results: These data indicate that each of the mechanical properties disproportionately increases across species with increasing green wood density, i.e., stems composed of denser green wood are disproportionately stiffer and stronger than stems with equivalent cross-sections composed of less dense green wood. * Conclusions: Although denser wood may have a higher carbon construction cost, the mechanical benefits of denser woods likely outweigh the extra cost. Key words:allometry; biomechanics; carbon construction costs; critical buckling height; tissue-density; wood stiffness; wood strength. doi: 10.3732/ajb.1000150

The specific gravity (SG) of wood is a measure of the amount of structural material a tree species allocates to support and strength. In recent years, wood specific gravity, traditionally a forester's variable, has become the domain of ecologists exploring the universality of plant functional traits and conservationists estimating global carbon stocks. While these developments have expanded our knowledge and sample of woods, the methodologies employed to measure wood SG have not received as much scrutiny as SG's ecological importance. Here, we reiterate some of the basic principles and methods for measuring the SG of wood to clarify past practices of foresters and ecologists and to identify some of the prominent errors in recent studies and their consequences. In particular, we identify errors in (1) extracting wood samples that are not representative of tree wood, (2) differentiating wood specific gravity from wood density, (3) drying wood samples at temperatures below 100[degrees]C and the resulting moisture content complications, and (4) improperly measuring wood volumes. In addition, we introduce a new experimental technique, using applied calculus, for estimating SG when the form of radial variation is known, a method that significantly reduces the effort required to sample a tree's wood. Key words: increment borers; moisture content: oven drying; tree cores; Wiemann approximation; wood density: wood specific gravity. The abstract and key words are also provided in Spanish with the online version of this article. doi: 10.3732/ajb.0900243

Acoustic tools are increasingly used to estimate standing-tree (dynamic) stiffness; however, such techniques overestimate static stiffness, the standard measurement for determining modulus of elasticity (MOE) of wood. This study aimed to identify correction methods for standing-tree estimates making dynamic and static stiffness comparable. Sixty Pinus taeda L. trees, ranging from 14 to 19 years old, obtained from genetic tests established in the southeastern United States, were analyzed. Standing-tree acoustic velocities were measured using the TreeSonic tool. Acoustic velocities were also recorded in butt logs cut from the same trees using the Director HM200. A strong but biased relationship between tree and log velocities was observed, with tree velocities 32% higher (on average) than the corresponding log velocities. Two correction methods, one for calibrating tree velocities and one for accounting for differences in wood moisture content, were used to determine an adjusted MOE. After correction, adjusted MOE estimates were in good agreement with static longitudinal MOE values measured on clearwood specimens obtained from the trees, and no systematic bias was observed. The results of this study show that acoustic estimates of MOE on standing trees largely depend on how the data are processed and the reference method used. Des outils acoustiques sont de plus en plus utilises pour estimer la rigidite (dynamique) des arbres debout. Cependant, de telles mesures surestiment la rigidite statique, la technique standard pour determiner le module d'elasticite (MOE) du bois. Cette etude visait a identifier les methodes de correction des estimations sur les arbres debout pour rendre les valeurs de rigidite dynamique et statique comparables. Soixante tiges de Pinus taeda L. ont ete analysees. Elles etaient agees de 14 a 19 ans et provenaient de tests genetiques etablis dans le sud-est des Etats-Unis. La vitesse sonique dans les arbres debout a ete mesuree avec l'appareil TreeSonic. La vitesse sonique a aussi ete mesuree dans la bille de pied coupee chez les memes arbres avec le Director HM200. Une relation etroite mais biaisee a ete observee entre la vitesse sonique dans les arbres debout et les billes. La vitesse sonique etait en moyenne 32 % plus elevee dans les arbres que dans les billes. Deux methodes de correction ont ete utilisees pour determiner un MOE ajuste : une methode pour calibrer la vitesse sonique dans les arbres et une autre pour tenir compte de la difference d'humidite dans le bois. Apres avoir effectue la correction, les estimations du MOE ajuste correspondaient bien aux valeurs du MOE longitudinal statique mesure sur des echantillons de bois sain provenant des arbres et aucun biais systematique n'a ete observe. Les resultats de cette etude montrent que les estimations acoustiques du MOE chez les arbres debout dependent largement de la facon dont les donnees sont traitees et de la methode de reference utilisee. [Traduit par la Redaction], Introduction Mechanical properties are the most important wood characteristics for structural applications. Particularly important is the modulus of elasticity (MOE) or stiffness, which provides a measure of a wood member's [...]

Wind can alter plant growth and cause extensive, irreversible damage in forested areas. To better understand how to mitigate the effects of wind action, we investigated the sensitivity of tree aerodynamic behavior to the material and geometrical factors characterizing the aerial system. The mechanical response of a 35-yr-old maritime pine (Pinus pinaster, Pinaceae) submitted to static and dynamic wind loads is simulated with a finite element model. The branching structure is represented in three dimensions. Factor effects are evaluated using a fractional experimental design. Results show that material properties play only a limited role in tree dynamics. In contrast, small morphological variations can produce extreme behaviors such as either very little or nearly critical dissipation of stem oscillations. Slender trees are shown to be relatively more vulnerable to stem breakage than uprooting. Dynamic loading leads to deflections and forces up to 20% higher near the base of the tree than those calculated for a static loading of similar magnitude. Effects of branch geometry on dynamic amplification are substantial yet not linear. The flexibility of the aerial system is found to be critical to reducing the resistance to the airflow and thus to minimizing the risk of failure. Key words: acclimatization; architecture; damping ratio; dynamics; numerical analysis; Pinus pinaster; sway frequency; tree biomechanics; wind.

Wood properties and growth were measured on breast-height cores and on disks collected at different heights from a thinned and fertilized midrotation loblolly pine (Pinus taeda L.) plantation in the lower Coastal Plain of North Carolina. The study was laid out in a randomized complete-block design receiving four levels of nitrogen (N) fertilizer: unfertilized control and 112, 224, and 336 kg/ha plus 28 kg/ha of phosphorus with each treatment. The effect of fertilization was analyzed for the whole-disk and for a 4 year average following fertilization on data collected from breast-height cores and from disks. The fertilization treatments did not significantly affect whole-disk wood properties but significantly increased radial growth. Fertilization rate of 336 kg/ha N significantly reduced 4 year average ring specific gravity and latewood specific gravity. Wood properties of trees that received 112 and 224 kg/ha N were not affected following treatment. There was no height related trend in wood property changes due to fertilization. Fertilization significantly increased ring basal area and earlywood basal area. In summary, there was a decline in wood properties and an increase in basal area growth immediately after fertilization; both depended on the rate of fertilizer applied irrespective of height. Les auteurs ont mesure les proprietes du bois et la croissance sur des carottes prelevees a hauteur de poitrine et des disques preleves a differentes hauteurs dans une plantation a mi-revolution de pin a encens (Pinus taeda L.) eclaircie, fertilisee et situee dans la basse plaine cotiere de la Caroline du Nord. L'experience etait structuree en blocs complets aleatoires dans lesquels quatre niveaux de fertilisant azote ont ete appliques : temoin, 112, 224 et 336 kg/ha, et 28 kg/ha de phosphore ont ete ajoutes a chaque traitement. L'effet de la fertilisation a ete analyse sur les moyennes des disques entiers et les moyennes des 4 annees suivant le traitement a partir des donnees mesurees sur les carottes et les disques. Les traitements de fertilisation n'ont pas eu d'effet significatif sur les proprietes du bois a l'echelle du disque entier mais ont cause une augmentation significative de la croissance radiale. Un taux de fertilisation azotee de 336 kg/ha a entraine une reduction significative de la densite relative moyenne des cernes annuels et du bois final des 4 annees suivant le traitement. Les traitements de fertilisation azotee a 112 et 224 kg/ha n'ont pas eu d'effet sur les proprietes du bois. Les changements des proprietes du bois dus a la fertilisation n'ont suivi aucune tendance reliee a la hauteur dans l'arbre. La fertilisation a cause une augmentation significative de la surface terriere des cernes et du bois initial. En resume, les proprietes du bois ont decline et la croissance en surface terriere a augmente immediatement apres la fertilisation mais chacun de ces effets dependait du taux de fertilisation utilise peu importe la hauteur. [Traduit par la Redaction], Introduction Midrotation application of thinning and fertilization is a widely accepted management practice in pine plantations growing throughout world. In the southeastern United States the adoption of this practice has [...]

Wood anatomical studies in the economically important Apocynaceae or dogbane family are fragmentary. This study represents a first attempt to unravel the phylogenetic significance and major evolutionary trends in the wood of the family, using existing and new microscopic wood observations within the large subfamily Rauvolfioideae. On the basis of LM and SEM observations of 91 species representing all 10 currently recognized tribes, we found that most of the tribes are characterized by a unique combination of wood characters, such as vessel grouping, vessel element length, fiber type, frequency of uniseriate rays, and fused multiseriate rays. Climbing rauvolfioid taxa can generally be distinguished from erect species by their wider vessels, tendency to form paratracheal axial parenchyma, presence of tracheids, and occurrence of laticifers in rays. With respect to the entire family, there is a general phylogenetic trend toward shorter vessel elements, a higher proportion of vessels in multiples and more vessels per multiple, higher tracheid abundance, more paratracheal parenchyma, and fewer cells per axial parenchyma strand in the more derived Apocynaceae. Most of these evolutionary trends are likely to be triggered by drier environmental conditions and/or shifts from an erect to a climbing habit. Key words: Apocynaceae; APSA clade; climbing vs. nonclimbing habit; Rauvolfioideae; systematic wood anatomy; tribal classification.

The weight percentage gain (WPG) and the acetyl group content of wood due to acetylation with acetic anhydride have been analyzed by means of Fourier transform infrared spectroscopy (FTIR) and near-infrared spectroscopy (NIR). Band height ratios (BHR) (1240/1030 (1230/ 1030) and 1745/1030 (1740/1030)) of the bands at 1745 (1740), 1240 (1230), and 1030 [cm.sup.-1] were calculated from FTIR-KBr and FTIR-ATR (attenuated total reflection) spectra. The good linear correlation with a coefficient of determination of about 0.94 over a range from 0 to 27% WPG existing between BHRs and WPG and acetyl group content, respectively, requires only a few samples to calibrate FTIR. Partial least-squares regression models based on second derivatives of the NIR spectra in the wavenumber range from 6080 to 5760 [cm.sup.-1] resulted in a [R.sup.2] value of 0.99, number of PLS components (rank) between 3 and 5, root-mean-square error of cross-validation between 0.6 and 0.79%, and a residual prediction deviation up to 10. Although a wide range of input parameters (i.e., various wood species and different procedures of acetylation) was used, highly satisfactory results were obtained. Both FTIR and NIR spectroscopic means fulfill the need for determining the WPG and the acetyl content of acetylated wood. By reason of its additional potential for on-line process control, the NIR method may even outperform the FTIR method.

Coarse woody debris is an important structural component of both terrestrial and aquatic ecosystems. We investigated coarse woody debris size-structure, decay class composition and distribution within the interface between second growth mixed conifer-hardwood forests and perennial streams in a catchment of the Lake Superior watershed on the Keweenaw Peninsula, Michigan. Down dead wood accumulation was nonlinearly distributed along transects perpendicular to streams and reached a peak between 30 and 50 m away from the wetted stream channels. Variability in the abundance of standing snags displayed a significant increase with distance. The coarse wood accumulations we observed were consistent with levels reported for upland, second-growth forests and were low compared to old-growth forest remnants in the region. Large (>40 cm diam) down dead wood will probably be the slowest pool to recover from logging and land clearing activities that occurred in the watershed prior to the turn of the 19th Century. Nevertheless, the large woody debris, especially highly-decayed wood, at the sites we examined was relict white pine (Pinus strobus) stumps, a persistent legacy of those same historic anthropogenic disturbances. Unlike dead wood, we detected no similar spatial distributions of living woody biomass. The small diameter of the existing standing wood suggests there will be a lag in the recruitment of new large dead wood into this ecosystem.

The hysteretic behavior of wood shear walls subjected to cyclic loading exhibit highly nonlinear force-displacement responses. There exists a careful balance between model complexity and necessary accuracy. In fact, the most widely used models for hysteretic behavior utilize piecewise-linear functions with static parameters to model the nonlinear hysteretic response and are often unable to capture some of the significant characteristics observed under experimental testing. This paper describes a new evolutionary parameter hysteretic model (EPHM) and illustrates its use in a number of applications including the development of seismic fragility curves. The proposed model is validated using the results of two full-scale shake table tests and eight cyclic shear wall tests with varying wall configurations and tested using different loading protocols. Good agreement is observed between the EPHM model and the test data. The EPHM is shown to be a better choice of hysteretic model than a static parameter model for performance-based seismic design applications when accurate prediction of displacement throughout the entire deformation demand range is required. DOI: 10.1061/(ASCE)0733-9445(2007)133:8(1118) CE Database subject headings: Cyclic tests; Earthquake engineering; Hysteresis; Shear walls; Wood; Parameters.

Lianas (woody vines) are an important and dynamic component of many forests throughout the world, and increases in C[O.sub.2], mean winter temperature, and forest fragmentation may promote their growth and proliferation in temperate forests. In this study, we used a 45-year data set to test the hypothesis that lianas have increased in abundance and basal area in the interiors of 14 deciduous temperate forests in Wisconsin (USA) since 1959. We also censused woody plants along a gradient from the forest edge to the interior in seven of these forests to test the hypothesis that the abundance of lianas declines significantly with increasing distance from the forest edge. We found that lianas did not increase in abundance within the interiors of temperate forests in Wisconsin over the last 45 years. However, relative and absolute liana abundance decreased sharply with increasing distance from forest edges. Our findings suggest that forest fragmentation, not climate change, may be increasing the abundance of lianas in northern deciduous temperate forests, and that lianas may further increase in abundance if the severity of forest fragmentation intensifies. Key words: climate change; edge effects; forest fragmentation; lianas, distribution and abundance; temperate forests; Wisconsin, USA, deciduous forests.

Electron paramagnetic resonance (EPR) signals of both modern and ancient wooden taxa are studied in order to analyze some features of the free radicals in natural wood. Microwave power saturation behaviors of seasoned wooden samples are studied and remarkable differences are found between softwoods and hardwoods.

Distributions of longitudinal relaxation times are computed separately for the solid and liquid components, giving also the solid/liquid [.sup.1.H] [alpha]. From measurements on the samples dried, seasoned, and hydrated, the moisture content is found to be approximately 0.50/[alpha].