In the present work a thinning program and a model describing dynamic of crown base recession for Eucalyptus grandis was established on an individual tree basis. Therefore, 485 trees were measured on temporary plots in forests of the companies Klabin Riocell (Guaíba), Todeschini (Cachoeira do Sul), the Federal University of Santa Maria and Aracruz Company, located in Rio Grande do Sul, Espirito Santo and Bahia, Brazil. A straight relationship between crown width and diameter at breast height (DBH) was found by using regression analysis. The equation obtained was crown width = e0.504+0.0307* DBH, with a coefficient of determination of 0.78 and a standard error of 0.034. With this equation the standing space of the individual trees was calculated over the whole rotation period, taking into account a crown cover of 70 %. Therefore the number of trees which can be grown on a hectare was derived for different variants of management systems aiming to produce eucalypt sawlogs in short rotation periods. Beside this a multivariate model describing height of crown base as a function of DBH and total height was found. Based upon this model the dynamics of crown base recession for different site qualities and thinning regimes are described, giving advice for time and intensity of green pruning.

Mimosa scabrella Benth. is an important native species of southern Brazil widely used for energy and promising for reforestation carbon offsets. Quantification of biomass and carbon stock is valuable for both purposes. From a forest inventory conducted in southern Brazil, data of M. scabrella were analyzed. Thirty sample trees were felled, excavated and weighed in the field and brought to laboratory for biomass and carbon determination. The total aboveground biomass represented 85% of the tree biomass, while roots corresponded to 15%. Correlation matrix of diameter at 1.3 m height (D), tree height (H) versus total and compartment biomass (P) indicated strong association between tree dimensions and biomasses. Five regression models were tested and equations were fitted to data of five biomass compartments and total tree biomass. The best fitting model for total biomass was P =-0.49361 + 0.034865 × D 2 H whereas for the partial biomass of the compartments was lnP = β 0 + β 1 × ln(D) + β 2 lnH. Carbon concentration was statistically significantly different in foliage than in other compartments. Three approaches of calculating carbon stocks were evaluated and compared to actual data: 1) Estimated total biomass × weighted mean carbon concentration; 2) Estimated partial (compartment) biomass × compartment average carbon concentration; and 3) Carbon regression equations. No statistical difference was detected among them. It was concluded that biomass equations fitted in this study were accurate and useful for fuelwood and carbon estimations.

Eucalypts are renowned for their high growth stress levels. These stresses cause splitting, warping and dimensional instability when cutting, processing and drying the wood. In Chile, large Eucalyptus nitens plantations can be found, which, due to these problems, are scarcely utilised for solid wood products (veneer, sawn wood). This study aims to determine the factors influencing growth stress at different stages of tree's development, and to identify whether the factors influencing growth stress change over time. In five stands of different ages, growth strain, as an indicator of growth stress, was measured at different tree heights with the single hole drilling method. The tree variables DBH, tree height, slenderness (height/diameter ratio) and crown parameters also were measured. A correlation analysis of tree variables and growth strains was undertaken. The results obtained indicate a high variability in growth strain values. It was concluded that growth strain is not correlated with a single growth parameter, but with a combination of factors that variously influence it at different ages and tree heights.

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-The objective of the present work was to analyse diameter growth and the relationship of natural pruning and various morphological characteristics of Parana pine (Araucaria angustifolia (Bert.) O Ktze.) growing on different sites in southern Brazil and to formulate silvicultural strategies for producing high quality timber for this species. Data on four hundreds trees in both natural and planted forests were collected on temporary sample plots each containing 25 Parana pines. The size of the knotty core within Parana pine stems was modeled with the predictor variables height of the lowest dead branch, height to crown base and maximum radial increment of stem at 1.3 m. The results of our study show that crown width is a good estimator of diameter growth and is closely related to stem diameter at 1.3 m above ground. Restricting crown expansion such that average annual radial increment is 4 mm/year at 1.3 m for a stem grown for 63 years compared to one grown for 36 years with less crown restriction such that the average annual radial increment is about 75% greater (7 mm/year) results in a knotty core volume that is about 75% less for the slower growing tree. Managers can use this model to guide silvicultural decisions needed to achieve the production goal of high quality wood of Parana pine.growing space / diameter growth / high valued timber / natural pruning / artificial pruning Résumé -Gérer la croissance en diamètre et l'élagage naturel du pin du Parana (Araucaria angustifolia (Bert.) O Ktze. pour produire un bois de haute valeur. L'objectif de ce travail a été d'analyser la croissance en diamètre et les relations entre l'élagage naturel et différentes caractéristiques du Pin de Parana (Araucaria angustifolia (Bert.) O Ktze) poussant dans différents sites dans le sud du Brésil et de formuler des stratégies sylvicoles pour produire du bois de haute qualité. Quatre cents arbres dans des peuplements naturels et plantés ont été collectés dans des placettes temporaires comprenant chacune 25 arbres. La grosseur des coeurs branchus dans les trouées a été modélisée avec des variables prédictives : hauteur de la plus basse branche morte, hauteur de la base de la couronne et accroissement radial maximum à 1,3 m. Les résultats de l'étude montrent que la largeur de la couronne est un bon estimateur de la croissance en diamètre et qu'elle est étroitement reliée au diamètre du tronc à 1,3 m. La limitation de l'expansion de la couronne de telle manière que l'accroissement annuel moyen atteigne 4 mm/an à 1,3 m pour un arbre ayant poussé depuis 63 ans en comparaison avec un autre qui a poussé depuis 36 ans avec une limitation moindre de la croissance de la couronne tel que l'accroissement en diamètre soit d'environ 75 % plus grand (7 mm/an), a pour résultat un volume de noeud plus faible d'environ 75 % que pour l'arbre ayant poussé plus lentement. Les aménagistes peuvent utiliser ce modèle pour les guider et décider des sylvicultures nécessaires pour atteindre un objectif de production de bois de haute qualité.espace ...