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This study was conducted to quantify growth responses of three major commercial conifer species (lodgepole pine (Pinus contorta Douglas ex Loudon var. latifolia Engelm. ex S. Watson), interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco), and spruce (white spruce (Picea glauca (Moench) Voss) and hybrid spruce (Picea engelmannii Parry ex. Engelm. x Picea glauca (Moench) Voss x Picea sitchensis (Bong.) Carriere))) to various fertilizer blends in interior British Columbia, Canada. Over 25 years, growth-response data were repeatedly collected across 46 installations. The fertilizer blends were classified into three groups: nitrogen only; nitrogen and sulfur combined; and nitrogen, sulfur, and boron combined. The growth responses for stand volume, basal area, and top height were calculated through absolute and relative growth rate ratios relative to a controlled group. Fertilizer blend, inverse years since fertilization, site index, stand density at fertilization, and their interactions with the fertilizer blend were used as explanatory variables. The magnitude and significance of volume and basal area growth responses to fertilization differed by species, fertilizer-blend groups, and stand-condition variables (i.e., site index and stand density). In contrast, the response in top height growth did not differ among fertilization blends, with the exception of the nitrogen and sulfur fertilizer subgroup for lodgepole pine. The models developed in this study will be incorporated into the current growth and yield fertilization module (i.e., Table Interpolation Program for Stand Yields (TIPSY)), thereby supporting guidance of fertilization applications in interior forests in British Columbia. Key words: fertilization gain, growth and yield model, Pinus contorta, Pseudotsuga menziesii, Picea glauca, Table Interpolation Program for Stand Yields (TIPSY). Cette etude visait a quantifier la reaction de croissance de trois importantes especes commerciales de coniferes (pin tordu latifolie (Pinus contorta Douglas ex Loudon var. latifolia Engelm. ex S. Watson), douglas de Menzies bleu (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco) et epinette (epinette blanche (Picea glauca (Moench) Voss) et epinette hybride (Picea engelmannii Parry ex. Engelm. x Picea glauca (Moench) Voss x Picea sitchensis (Bong.) Carriere)) a divers melanges de fertilisants appliques dans la zone interieure de la Colombie-Britannique, au Canada. Les donnees de reaction de croissance ont ete recoltees de facon repetee sur une periode de 25 ans dans 46 installations. Les melanges de fertilisants ont ete classes en trois groups : azote seul, azote et soufre combines, et azote, soufre et bore combines. Les reactions de croissance en volume, en surface terriere et en hauteur dominante du peuplement ont ete calculees en valeurs absolues et en rapports de taux de croissance relatif a un groupe temoin. Les variables explicatives etaient le melange de fertilisants, l'inverse du nombre d'annees depuis la fertilisation, l'indice de qualite de station, la densite du peuplement au moment de la fertilisation et leurs interactions avec le melange de fertilisants. L'ampleur et la significativite statistique des reactions de croissance en volume et en surface terriere a la fertilisation differaient selon l'espece, le groupe de melange de fertilisants et les variables d'etat du peuplement (c.-a-d. l'indice de qualite de station et la densite du peuplement). Par contre, la reaction de croissance en hauteur dominante n'a pas varie en fonction des melanges de fertilisants, a l'exception du melange d'azote et de soufre combines dans le cas du pin tordu. Les modeles mis au point dans cette etude seront incorpores au module actuel de fertilisation pour la croissance et le rendement (c.-a-d. TIPSY) de facon a appuyer les directives pour les applications de fertilisants dans les forets interieures de la Colombie-Britannique. [Traduit par la Redaction] Mots-cles : benefices de la fertilisation, modele de croissance et rendement, Pinus contorta, Pseudotsuga menziesii, Picea glauca, Programme d'interpolation tabulaire pour les rendements des peuplements (TIPSY)., Introduction Forests are one of the most important natural resources in British Columbia (BC), Canada, and are closely connected with the industry, economy, and culture of BC communities. Climate change [...]

Western gall rust (Cronartium harknessii (J.P. Moore) E. Meinecke) is a pathogen that affects lodgepole pine (Pinus contorta Douglas ex Loudon var. latifolia Engelm. ex S. Watson) and has the potential to reduce lumber product yields derived from stands managed for the commercial production of timber. A dataset containing repeated measurements from 7775 trees located within the province of British Columbia, Canada, was used to develop equations that predict annual rates of stem infection, post-infection mortality, and the location of large stem galls. Results showed that annual rates of infection peaked between 3 and 5 years following stand establishment. Few new infections were predicted to occur beyond the stand age of 15 years. For an individual tree, the probability of first infection increased as its height increased relative to stand top height. The rate of mortality increased with the number of stem infections and was highest among trees infected within the first 3 years following planting. Mortality rates decreased thereafter, with many trees likely to survive to rotation. The equations predicting rust incidence and mortality were added to the Tree and Stand Simulator (TASS), an individual-tree growth model used within the province. A final equation predicting the location of large galls was added and allows TASS to account for losses due to the removal of stem defects during lumber manufacturing. Key words: Western gall rust, growth simulator, lodgepole pine, merchantable and lumber volume. La rouille-tumeur autonome causee par Cronartium harknessii (J.P. Moore) E. Meinecke infecte le pin tordu latifolie (Pinus contorta Douglas ex Loudon var. latifolia Engelm. ex S. Watson) et peut reduire les rendements en produits derives du bois provenant de peuplements amenages pour la production commerciale de bois d'oeuvre. Une base de donnees contenant des mesures repetees de 7775 arbres situes dans la province de la Colombie- Britannique, au Canada, a ete utilisee pour elaborer des equations qui predisent les taux annuels d'infection du tronc et de mortalite due a l'infection, ainsi que la position des grosses galles sur le tronc. Les resultats montrent que le taux annuel d'infection culmine 3 a 5 ans apres l'etablissement du peuplement. Selon les predictions, peu de nouvelles infections surviennent apres que le peuplement ait atteint l'age de 15 ans. Dans le cas d'un individu, la probabilite d'une premiere infection augmente a mesure que la hauteur de l'arbre augmente relativement a la hauteur maximale du peuplement. Le taux de mortalite augmente avec le nombre d'infection du tronc et il etait le plus eleve parmi les arbres infectes au cours des 3 premieres annees apres la plantation. Le taux de mortalite diminue par la suite et plusieurs arbres ont des chances de survivre jusqu'a la fin de la rotation. Les equations qui predisent l'incidence et la mortalite associees a la rouille ont ete ajoutees au simulateur TASS, un modele de croissance d'arbre individuel utilise dans la province. Une derniere equation qui predit la position des grosses galles a ete ajoutee, ce qui permet au simulateur TASS de tenir compte des pertes causees par l'elimination des defauts du tronc lors de la transformation en bois d'oeuvre. [Traduit par la Redaction] Mots-cles : rouille-tumeur autonome, simulateur de croissance, pin tordu latifolie, volume total de bois et volume marchand., Introduction Western gall rust (Cronartium harknessii (J.P. Moore) E. Meinecke) is a fungal pathogen that affects hard pines. In the province of British Columbia (BC), Canada, it is among the [...]

We examined modulus of elasticity (MoE) derived from SilviScan in white spruce (Picea glauca (Moench) Voss) at the site, tree, and ring levels across the Boreal Plains ecozone in Canada. Area-weighted averages of MoE were calculated for juvenile and mature wood and were examined in relation to radial growth, climate, and location. Correlations indicated that there was a negative relationship between radial growth and MoE in the juvenile wood that was detectable at the site and tree levels; however, the relationship weakened in the mature wood, particularly at the site level. Few climate variables were correlated with MoE in juvenile wood, whereas multiple summer and fall climate variables showed a significant correlation with MOE in mature wood. A model describing the radial profile of MoE explained 58% of the variability in MoE, with 10% of the random variability attributed to between-tree differences. Elevation and summer water balance accounted for nearly all of the betweensite variability. A decrease in MoE with increasing elevation was noted and has been previously linked to a decrease in cell wall thickness due to a shorter growing season at higher elevations. Integration of the MoE profile model into an individual-tree growth and yield simulator is the next logical step. Key words: wood stiffness, white spruce, climate, Boreal Plains, radial growth. Nous avons etudie le module d'elasticite (MoE) derive de SilviScan chez l'epinette blanche (Picea glauca (Moench) Voss) a l'echelle de la station, de l'arbre et du cerne annuel a travers l'ecozone des plaines boreales au Canada. Des moyennes du MoE ponderees par la superficie ont ete calculees pour le bois juvenile et le bois mature et ont ete etudiees en relation avec la croissance radiale, le climat et la station. Les correlations indiquent qu'il existe une relation negative entre la croissance radiale et le MoE dans le bois juvenile qui est detectable a l'echelle de la station et de l'arbre. Cependant, cette relation s'attenue dans le bois mature, particulierement a l'echelle de la station. Peu de variables climatiques sont correlees avec le MoE dans le bois juvenile tandis que de multiples variables climatiques d'ete et d'automne sont significativement correlees avec le MoE dans le bois mature. Un modele decrivant le profil radial du MoE explique 58 % de la variabilite du MoE et 10 % de la variabilite aleatoire est attribuee aux differences entre les arbres. L'altitude et le bilan hydrique estival expliquent presque toute la variabilite entre les stations. Une diminution du MoE avec l'augmentation de l'altitude a ete notee et a precedemment ete reliee a une diminution de l'epaisseur de la paroi cellulaire due a une saison de croissance plus courte a plus haute altitude. L'integration du modele du profil du MoE dans un simulateur de croissance et rendement d'arbres individuels est la prochaine etape logique. [Traduit par la Redaction] Mots-cles : rigidite du bois, epinette blanche, climat, plaines boreales, croissance radiale., Introduction White spruce (Picea glauca (Moench) Voss) is often used for the production of structural lumber or plywood because of its relatively low mass and high stiffness (i.e., modulus of [...]

White spruce (Picea glauca (Moench) Voss) and aspen (Populus tremuloides Michx.) from unmanaged stands in the boreal forest of Alberta, Canada, were examined for two of the main structural assumptions in the process-based model CROBAS: (i) a constant allometric relationship between foliage mass and crown length and (ii) a constant relationship between foliage mass and sapwood area. We evaluated these relationships at both at the whole-crown and within-crown levels. Results indicated that for both species, a constant allometric relationship between foliage mass and crown length was maintained at the whole-crown level over a period exceeding the peak mean annual increment of each species. Within the crowns of spruce, foliage mass accumulated faster near the tree apex as total crown length increased. For aspen, the increase in foliage mass per unit crown length for any section within the crown showed greater similarity to the relationship observed at the whole-crown level. The assumption of a constant relationship between foliage mass and sapwood area at the crown base generally held for spruce but showed considerable variation for any given diameter class. For aspen, this assumption did not appear to be appropriate. For both species, there was more foliage mass per unit sapwood area with increasing height from the ground for nearly all tree size classes. This latter finding was in conflict with the pipe model theory but could not be explained by the hydraulic theory of crown architecture, which predicts a decrease in the ratio of foliage mass to sapwood area with increasing path length. Key words: pipe model, crown allometry, foliage mass, Picea glauca, Populus tremuloides. A partir d'epinettes blanches (Picea glauca (Moench) Voss) et de peupliers faux-tremble (Populus tremuloides Michx.) provenant de peuplements boreaux non amenages de l'Alberta, nous avons etudie deux des principales hypotheses structurales du modele fonctionnel CROBAS : (i) une relation allometrique constante entre la masse foliaire et la longueur de la cime, et (ii) une relation constante entre la masse foliaire et la surface d'aubier. Nous avons evalue ces relations aux echelles de la cime entiere et de l'interieur de la cime. Les resultats indiquent que pour les deux especes, une relation allometrique constante entre la masse foliaire et la longueur de la cime a ete maintenue a l'echelle de la cime entiere au cours d'une periode depassant l'age d'atteinte de l'accroissement annuel moyen maximal de chaque espece. Dans les cimes d'epinette, la masse foliaire s'accumulait plus rapidement pres de l'apex de l'arbre a mesure que la longueur totale de la cime augmentait. Chez le peuplier, l'augmentation de la masse foliaire par unite de longueur de cime de toutes les sections de la cime ressemblait davantage a la relation observee a l'echelle de la cime entiere. L'hypothese d'une relation constante entre la masse foliaire et la surface d'aubier a la base de la cime a generalement ete validee pour l'epinette, mais sa variation etait considerable pour toutes les classes de diametre. Dans le cas du peuplier, cette hypothese ne semblait pas appropriee. Chez les deux especes, la masse foliaire par unite de surface d'aubier augmentait avec la hauteur par rapport au sol pour a peu pres toutes les classes de taille d'arbre. Ce dernier resultat contredit la theorie du modele tubulaire, mais ne peut etre explique par la theorie hydraulique de l'architecture de la cime qui predit une diminution du rapport entre la masse foliaire et la surface d'aubier avec l'augmentation de la distance de transport. [Traduit par la Redaction] Mots-cles : modele tubulaire, allometrie de la cime, masse foliaire, Picea glauca, Populus tremuloides., Introduction CROBAS (Makela 1997) is a process-based model that not only is based on the principle of carbon balance, but also incorporates principles related to the functional balance (Davidson 1969; [...]

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 [...]

A system of equations was developed to predict crown length (CL) and crown radius (CRAD) for trees in structurally complex stands. The equations address two problems that often arise in crown allometry. First, relationships between the main stem and the crown are likely to change with intertree competition. Therefore, explicit measures of density were used along with main stem measurements as explanatory variables. Second, the physiological relationship between CL and CRAD is often overlooked when modeling crowns. This relationship is incorporated through the use of a simultaneous system of equations. Parameters were estimated using nonlinear three-stage least squares (N3SLS) in which first-stage equation estimates of CRAD are used to estimate CL and vice versa in the second and third stages of N3SLS. The equations were fitted and validated for four species: lodgepole pine (Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson), hybrid spruce (Picea engelmannii Parry ex Engelm. x P. glauca (Moench) Voss), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco), and trembling aspen (Populus tremuloides Michx.). The intent is to use the equations as alternatives to the crown equations in the spatially explicit forest growth model SORTIE-ND that use only main stem variables in estimating crowns over time. Un systeme d'equations a ete developpe pour predire la longueur (LC) et le rayon (RC) de la cime des arbres dans des peuplements structurellement complexes. Les equations abordent deux problemes d'allometrie de la cime qui se posent souvent. Premierement, il est probable que les relations entre la tige principale et la cime changent en fonction de la competition entre les arbres. Par consequent, des mesures explicites de densite ont ete utilisees avec des mesures de la tige principale comme variables explicatives. Deuxiemement, la relation physiologique entre LC et RC est souvent negligee lorsqu'on modelise la cime. Cette relation est incorporee via l'utilisation d'un systeme simultane d'equations. Les parametres ont ete estimes a l'aide de la methode des moindres carres non lineaire qui comporte trois etapes; les estimations de RC generees par les equations de la premiere etape sont utilisees pour estimer LC et vice versa lors des deuxieme et troisieme etapes. Les equations ont ete ajustees et validees pour quatre especes: le pin tordu latifolie (Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson), l'epinette hybride (Picea engelmannii Parry ex Engelm. x P. glauca (Moench) Voss), le douglas de Menzies bleu (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco) et le peuplier fauxtremble (Populus tremuloides Michx.). L'intention est d'utiliser ces equations au lieu des equations de cime du modele de croissance forestiere spatialement explicite SORTIE-ND qui utilise seulement les variables de la tige principale pour estimer la cime a differents moments. [Traduit par la Redaction], Introduction Estimates of crown size are often used to infer tree vigor (Assmann 1970; Valentine et al. 1994), basal area increment (Hasenauer and Monserud 1996; Monserud and Sterba 1996), and [...]

Plant lesions affect disease impact, progression and host resistance. Root lesions caused by Armillaria ostoyae (Romagn.) Herink were inspected on 24‐ to 34‐year‐old planted Douglas‐fir (Pseudotsuga menziesii (Mirb.) Franco) pulled from the soil in five locations. Four hundred seventy‐nine lesions were measured for length (mm), expansion rate (mm/year) and lesion type. Lesion types were patch lesions on a root side, girdled lesions covering the root circumference and root collar lesions on the stem below ground. Non‐linear mixed modelling revealed that fungal lesion length at girdled and collar lesions increased but the expansion rate slowed as a power function of time, indicating increasing secondary inoculum and host resistance. Average fungal lesion expansion rate in girdled root and collar lesions was 127 mm the first year which then declined non‐linearly to 26 mm/year after 10 years. Fungal lesion length in patch lesions showed little change after the first year of infection. For girdled and collar lesions, fungal lesion length increased with tree size at the time of infection. Sites with a longer frost‐free period had shorter girdled root and stem lesions, probably because of more active host defence. Results indicate that mortality would be rare from one infection event. Furthermore, patch lesions pose a lower risk of mortality than other lesions because of a lower fungal lesion expansion rate and secondary inoculum. Tree size, lesion position, lesion type and fungal lesion expansion rate need to be considered when assessing the risk of lesions to individual tree survival. Techniques to minimize the disease impact are discussed. [ABSTRACT FROM AUTHOR]

We examined modulus of elasticity (MoE) derived from SilviScan in white spruce ( Picea glauca (Moench) Voss) at the site, tree, and ring levels across the Boreal Plains ecozone in Canada. Area-weighted averages of MoE were calculated for juvenile and mature wood and were examined in relation to radial growth, climate, and location. Correlations indicated that there was a negative relationship between radial growth and MoE in the juvenile wood that was detectable at the site and tree levels; however, the relationship weakened in the mature wood, particularly at the site level. Few climate variables were correlated with MoE in juvenile wood, whereas multiple summer and fall climate variables showed a significant correlation with MOE in mature wood. A model describing the radial profile of MoE explained 58% of the variability in MoE, with 10% of the random variability attributed to between-tree differences. Elevation and summer water balance accounted for nearly all of the between-site variability. A decrease in MoE with increasing elevation was noted and has been previously linked to a decrease in cell wall thickness due to a shorter growing season at higher elevations. Integration of the MoE profile model into an individual-tree growth and yield simulator is the next logical step. [ABSTRACT FROM AUTHOR]

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

Model-based prediction of annual ring density (RD) is necessary to manage forests for wood quality objectives. However, annual RD in lodgepole pine (Pinus contorta Dougl. ex Loud.) exhibits a high degree of variability making it achallenge to model. We compared two methods of predicting annual RDincluding (1) a ring component approach and (2) a direct approach. The former approach uses model-based estimates of earlywood density (EWD), latewood density (LWD) and latewood proportion (LWP) to calculate annual RD. The latter approach uses a single model with annual RD as the dependent variable. The two approaches were tested using a dataset which included sites on thewestern and eastern slopes of the Rocky Mountains, within the provinces of British Columbia and Alberta, Canada. The best models for EWD, LWD and LWP included ring number and ring width, while site-specific parameters indicated that sites on thewestern slopes differed fromthose on the eastern slopes. Component- based estimates of annual RD using only fixed effects explained 25 per cent of the variability, increasing to 63 per cent with random effects. The best model for a direct estimate of annual RD explained only 5 per cent of the variability using fixed effects, increasing to 55 per cent with random effects. [ABSTRACT FROM AUTHOR]

Highlights: [•] Predictive models for branch characteristics were developed for white spruce. [•] The models were for naturally regenerated mixedwood stands of the boreal forest. [•] Within-crown and tree-level variables were important predictor variables. [•] Stand-level competition and species composition did not factor into the models. [•] The models will be used to assess wood quality traits influenced by branching. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

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