Early evaluation of wood properties using test os seedlings

The early selection of trees is of great interest, both for pulp and paper companies, as well as for those that use wood in structures, furniture or other applications. This anticipation allows to accelerate the processes of genetic improvement, as well as those related to the forest management aiming to improve the quality of the wood produced. However, to anticipate the selection of wood using parameters that can be obtained in younger trees or even in seedlings, it is necessary to know how these parameters propagate with age and how it is related with wood from trees. Among the properties measurable in seedlings are those geometrics (diameter and height), physics (density), mechanicals (strength and stiffness) and acoustics (propagation of waves) and, among properties of the wood in trees are the density, strength and stiffness. Thus, the main goal of this research was to analyze the feasibility of obtaining models that allow predicting tree wood properties from measurable properties in seedlings. To achieve this goal, the behavior with age of measurable properties in seedlings was first analyzed. The research was carried out using 391 seedlings and trees from three commercial eucalyptus clones and four progenies of Pinus Pinaster, varying from 3 to 6 months (seedlings) up to 72 months (trees). Within the analyzed range of age, all the parameters measured in the seedlings presented potential to be used in a predictive model to anticipate properties of wood from older trees, but the degree of this anticipation is not the same. The velocity of ultrasound waves was the only property that maintained, at the cutting age (6 years), the coherence of the differentiation between clones obtained still as seedling. The strength, stiffness, diameter and height maintained coherence from 12 months to the cutting age, while the basic density from 24 months. The most suitable multiple regression model for the prediction of the stiffness of the tree wood was that involving the height and the velocity of wave propagation on seedlings. The prediction of the modulus of rupture was adequate with a simple regression model, using the relation between the modulus of elasticity and the rupture strength obtained in seedling steam tension test. The basic wood density of the tree could not be predicted by any model involving parameters obtained in seedlings of the same species (AU)