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The main objective of this study was to assess the properties of Nothofagus alpina wood from thinning that originates from two sites with intensive silviculture and one similar to a secondary growth forest, with different soil, climatic conditions and age. To achieve this, some mechanical, physical and chemical-crystalline properties were characterized; studying the differences from pith to bark and between the selected trees that were taken from the thinning of the three plantations. Among the studied plantation sites, there were statistical differences in equilibrium moisture content, density and modulus of elasticity. Furthermore, FT-IR was able to differentiate the chemical-crystalline compositions from pith to bark and between plantations, while the X-Ray Diffraction showed differences in the crystallinity index. It was possible to differentiate between the sites with a more intense silvicultural intervention and the one with more variable growth conditions.

Eucalyptus nitens is a fast growing plantation species that has a good acclimation in Chile. It is commonly used for pulp and paper, but there is a growing market for solid wood products made from this species and an interest on producing high quality material. Thermal modification technology have been used to obtain high quality product out of fast growing plantation species. In this study we modified Eucalyptus nitens to analyse the influences of the process conditions and evaluated its mechanical properties under several process conditions. The material was modified in a closed system under elevated pressure and controlled relative humidity (30 and 100% relative humidity) at temperatures between 150 and 170°C, and in an open system with a standard thermal modification procedure between 160 and 230°C. Modulus of elasticity, modulus of rupture, deflection and work in bending (in elastic and inelastic proportions) and the resistance to impact milling in high energy multiple impact tests were determined. Mass loss after each modification was also measured and correlated with the mechanical properties. Anatomical properties of selected modifications were analysed. There were no significant differences between open and closed system modifications in both mechanical and anatomical properties.