The objective of this study was to determine how final stocking influences tree growth and radial and longitudinal variation in wood properties at a Pinus radiata D. Don plantation located at one of the warmest forest sites in New Zealand, Forsyth Downs forest in Northland. This thesis addressed both the effect of stocking on stand basal area, height, diameter and branch diameter and the effect of stocking on wood properties microfibril angle (MFA), module of elasticity and density. Finally, how ring width influences wood properties and whether this variable accounts for the treatment effects was investigated. Stocking, height and ring number and all interactions between these variables significantly affected ring width. Ring width by itself was significant as a predictor of density, but when it was combined with other class level variables it was insignificant (i.e. does not account for treatment effects), and it did not add anything to a model with only class effects. There was a significant impact of ring number on density while ring width was insignificant in the same model. MFA was significantly affected by ring width, height and ring number in the tree, and all interactions, apart from the three way interaction, but not by stocking. Ring width was significant in the MFA model both by itself and when it was combined with other variables. Ring width accounted for the stocking effect. The best model of MOE included the class level effects of stocking, height and ring number within the tree, and all interactions between these variables, and ring width, as a continuous variable. While there was a significant effect between stockings this was relatively weak compared to the other main effects. Ring width largely accounted for the effect of stocking, but not that of ring number, or height.

Lic.-avh. (sammanfattning) Stockholm : Tekniska högskolan, 2006. / Härtill 2 uppsatser.

Diss. (sammanfattning) Stockholm : Kungliga Tekniska högskolan, 2008. / Härtill 5 uppsatser.

The ability to predict wood properties would aid in the growing of southern pine timber for specific end uses. Three wood properties, specific gravity, shrinkage, and knottiness, were chosen as the focus of this study. Silvicultural studies focusing on southern pine management were researched for any information on their impacts on wood properties. The information from silvicultural studies was then used to evaluate growth and yield models for ease of adaptation to predict wood properties. The information necessary to predict all wood properties is not currently available. Although, specific gravity has significantly more information available than the other properties and it is probably the most predictable.

No description available.

The limited range of commercial timber species in Great Britain has led the forestry sector to consider wider planting of other species. This research addresses wood properties, particularly relevant to structural timber, of noble fir, Norway spruce, western red cedar and western hemlock in Great Britain. Sampling covered three regions to get a representative sample for the country. Bending stiffness, bending strength, density and twist distortion from drying were assessed. The results showed high yields of C16 for all these species, with Norway spruce and western hemlock performing comparatively well to typical British-grown Sitka spruce. Within this dataset, variation of mechanical properties within trees was more important than differences between species. Strength and stiffness increased with age, whereas density followed different trends in the inner and outerwood. The three properties were modelled based on ring number. The use of acoustic techniques to assess the mechanical properties of wood (in particular stiffness), was investigated in clears, sawn timber, logs and trees. The best results were found combining density with acoustic velocity in sawn timber. The use of acoustic techniques in standing trees was more reliable measuring distances of two or three metres, rather than the commonly used one metre; most likely due to a change in the wave propagation. Tree architecture was studied for timber production and quality. Noble fir described the highest merchantable taper profile. Branchiness varied importantly with height in the stem, and models were built for number, diameter and angle of branches. Western red cedar and western hemlock had fewer but thicker branches compared to noble fir and Norway spruce. Future work should produce grading machine settings and address the variation of timber quality and merchantability under different silvicultural regimes. This thesis concludes that the four species investigated can contribute to diversity the timber industry in Great Britain.

In Norway spruce there's a large natural variation in durability but knowledge about what is causing this variation is missing. In this thesis the focus were put into investigating how the water uptake ability was affected by the influence of heartwood versus sapwood and wood properties such as density and annual ring width. Liquid water permeability was checked trough a modified version of EN 927-5 and samples were also investigated trough the Mycologg Method. The wide grown wood with a coating system (a priming oil and alkyd or acrylate paint) absorbed less water than the narrow grown wood in the permeability test. The Mycologg test showed a clear difference between wide and narrow grown wood. Further research is necessary to examine the impact of wood properties when it comes to water uptake.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2008. / Härtill 5 uppsatser.

No description available.

Les techniques de culture du pin maritime dans les Landes de Gascogne ont connu des changements importants à partir des années 1960. A côté de peuplements de sylviculture traditionnelle basée sur la régénération naturelle assistée, se sont succédés de nouveaux types de peuplements sous le vocable de « ligniculture ». La proportion de ces peuplements menés intensivement, dans la récolte des coupes rases en Aquitaine, va augmenter rapidement dans les dix prochaines années. Les données technologiques faisant actuellement défaut sur cette ressource, il est nécessaire d’anticiper dès aujourd’hui l’impact de ces pratiques sylvicoles sur les propriétés du bois.Des arbres ont été échantillonnés dans 14 parcelles réparties dans les Landes de Gascogne. Sur chaque parcelle, 4 arbres ont été sélectionnés pour les mesures des propriétés physiques. Les variations radiales de densité intra-cerne, de proportion de bois final, de duramen et d’angle du fil ont été mesurées. Parallèlement 8 arbres ont été exploités. Après sciage puis séchage, l’aspect visuel et les propriétés mécaniques des avivés obtenus ont été mesurés. Sur la base des données recueillies et de données d’études précédentes, des modèles déterministes ont été développés pour prédire les variations des caractéristiques étudiées. Ces modèles de la famille des modèles mixtes, sont constitués d’une partie « fixe » commune à l’ensemble des arbres et d’une partie aléatoire qui quantifie les écarts propres à la parcelle et aux arbres (appelés effet « parcelle » et effet « arbre »). Un modèle décrivant les variations avec la hauteur dans l’arbre du taux de duramen, basé sur l’âge des arbres a été développé, il explique plus de 70% de la variation. Les modèles décrivant les variations radiales de l’angle du fil, de la densité, et des propriétés mécaniques du bois ont un niveau de prédiction plus faible, mais un effet significatif de l'âge cambial et de la largeur de cerne sur ses propriétés a été mis en évidence. La vitesse de croissance a un impact négatif sur les propriétés mécaniques du bois de pin maritime.Appliqué à des scénarios sylvicoles ces modèles ont permis d'estimer le classement mécanique des sciages pouvant potentiellement être obtenus à partir de la ressource.Le transfert de ces modèles auprès des gestionnaires forestier pourrait permettre une meilleure estimation de la qualité des bois et donc leur meilleure allocation dans un contexte post tempête où la ressource en pin maritime en Aquitaine se fait rare. / The forest cultivation techniques of maritime pine in the South Western France deeply changed in the 1970’s. In particular the reforestation method shifted from assisted natural regeneration to intensive techniques including soil ploughing, phosphoric fertilization and seeding, then plantation with improved material in the 1980’s. As the proportion of “intensively cultivated” stands in final cut will increase drastically in the next decades, it is now necessary to anticipate the impact of these reforestation methods on the wood properties for the wood industry, from the analysis of the oldest.Trees were sampled from 14 stands in the South Western France covering a wide range of mean volume. On each stand, 4 trees were selected for physical properties measurement. Within ring wood density, latewood content, heartwood diameter and spiral grain angle were measured on wood disks collected at different heights within each tree. At the same time 8 trees were harvested and bucked into 2.2 m long logs. After drying, visual aspect and mechanical properties of the sawn boards were assessed.Based on the data, deterministic models were developed to predict the variables based on selected stand and tree characteristics. The models for heartwood content in cross section explain quite well the variation with height (more than 70% of the variation). The heights of green and dead branches were identified as important variables in the models for nature of knot in trees. The developed models, for spiral grain angle, radial variations of wood density and mechanical properties, have a relatively low level of prediction, but it has highlighted the effect of cambial age and ring width on these properties. The growth rate has so a negative impact on the mechanical properties of wood of maritime pine. Based on the mixed model analysis with repeated measurements structure, the trees and stand effect on the residual variation were estimated. Applied on silvicultural scenarios, these models have been used in a simplified approach to estimate the strength of timber that can potentially be obtained from the resource. The transfer of these models with forest managers could allow a better estimate of the quality of wood, and thus a better allocation in a post-storm context where the resource is scarce.