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Permeability functionalities are noticeable in the wood drying and impregnation processes because it has an effect on the bulk flow of a fluid through the wood structure. The aim of this work was to measure the radial and tangential specific gas permeability of Eucalyptus nitens wood for 10 different provenances. Furthermore, the effect of the radial position (defined as inner-wood, middle-wood, and outer-wood) on the measurements was investigated. The specific gas permeability of E. nitens ranged in order of magnitude from 10−20 to 10−16 m2. The results showed that the radial position had a statistically significant effect on the specific permeability in both flow directions and, in general, the permeability values increased from inner-wood to outer-wood. Moreover, the scanning electron microscopy images showed obstruction of vessels by tyloses which explained the lower permeability values obtained in the inner-wood of E. nitens. Differences in the magnitude of the permeability values could explain the diverse drying and impregnation behavior according to the wood zones, the low permeability values in the internal wood-zone could suggest an opportunity for improving it, through chemical modification or structural changes to introduce new functionalities of this radial wood-zone in Eucalyptus nitens.

Collapse is almost certain to occur in the industrial drying of Eucalyptus nitens and, as such this prevents the lumber manufacturing industry in Chile from producing commercial solid wood products from this species. This problem is still unsolved, and different studies to reduce collapse are currently underway. In this exploratory study, shrinkage and collapse after drying of Eucalyptus nitens was measured for boards cut from different radial locations within the stem (core, transition, and outer wood from pith to bark) and having different annual ring orientations (flat-sawn and quarter-sawn). Though exploratory, the results appear to confirm that pieces that were cut from the center of the trees were less susceptible to collapse than pieces cut from the transition zone between the center and the periphery. On average, collapse in transition wood was approximately 50% higher than the collapse observed in wood cut from the central zone of the trees.

Collapse and drying stresses are currently induced during the drying of Eucalyptus nitens in solid wood products. The purpose of this study was to investigate these drying stresses by measuring hygromechanical strains during the drying of Eucalyptus nitens boards. Small samples of Eucalyptus nitens wood were oriented in the radial and tangential directions and tested to determine the hygromechanical strains during the drying process. This experimental work consisted of cantilevered bending tests conducted under variable relative humidity conditions. Tests were performed in a conditioning chamber at 30 °C with an equilibrium moisture content ranging from 22 to 12% under four levels of stress: 0, 10, 20 and 30% of the rupture load. The strains were determined using strain gauges, and the total deflection was measured with a linear variable differential transformer. The results show that in hygromechanical strains during the drying of Eucalyptus nitens, both the surface deformation and mechano-sorption strain were found to be proportional to the applied stress and reached their maximum values in the tangential direction. The total deflection increased 0,18 mm/mm with a surface deformation of 0,20 mm/mm, and the mechano-sorptive strain provides a greater contribution with a value of 0,11 mm/mm, thus corresponding to 59% of the total deformation. In attempts to improve the drying schedules of Eucalyptus nitens to develop solid wood products, mechano-sorptive behavior may be applied to relieve collapse and drying stress.

The occurrence of internal checks and their relationship with anatomical structure and basic density in three clones of Eucalyptus nitens plantation trees grown in the eighth region of Chile were studied. Two trees per clone were sampled. The number, radial location, and length of internal checks were determined in samples oven-dried at temperatures increasing from 50 to 100 C. Wood anatomical features including vessel frequency and diameter and annual growth ring width were measured by image analysis. Results show that internal checks were greater for clones with lower basic density. Internal check frequency decreased with height in the tree and increased from pith to bark. A low wood basic density was related to greater ring width and vessel frequency, which contributed to the development of internal checks.

This paper studies the relationship between apparent density and some anatomical properties of Eucalyptus nitens such as vessel frequency, vessel area, ring width, fiber cell wall thicknesses, and fiber length. The study involved 29 trees from 10 families of Eucalyptus nitens cut from a 17-yr-old plantation in Southern Chile. The properties were determined along the radial direction of the trees by using X-ray equipment and at selected positions through microscope and fiber quality analyzer equipment. The results showed that the anatomical properties of E. nitens did not change gradually from pith to bark, but they were better described by dividing the tree radius into three different wood-zones referred as inner-, middle-, and outer-wood. The apparent density of E. nitens was dependent of the vessel area, cell wall area, ring width, and latewood width. The correlation coefficient between apparent density and vessels area was negative and the correlation coefficient between apparent density and cell wall area, latewood ring width, and total ring width were positive. These means that E. nitens wood with lower density tended to have higher vessel area, and lower fiber cell wall area, ring width, and latewood width.

This paper studies the relationship between apparent density and some anatomical properties of Eucalyptus nitens such as vessel frequency, vessel area, ring width, fiber cell wall thicknesses, and fiber length. The study involved 29 trees from 10 families of Eucalyptus nitens cut from a 17-yr-old plantation in Southern Chile. The properties were determined along the radial direction of the trees by using X-ray equipment and at selected positions through microscope and fiber quality analyzer equip- ment. The results showed that the anatomical properties of E. nitens did not change gradually from pith to bark, but they were better described by dividing the tree radius into three different wood-zones referred as inner-, middle-, and outer-wood. The apparent density of E. nitens was dependent of the vessel area, cell wall area, ring width, and latewood width. The correlation coefficient between apparent density and vessels area was negative and the correlation coefficient between apparent density and cell wall area, latewood ring width, and total ring width were positive. These means that E. nitens wood with lower density tended to have higher vessel area, and lower fiber cell wall area, ring width, and latewood width.

Collapse and drying stresses are currently induced during the drying of Eucalyptus nitens in solid wood products. The purpose of this study was to investigate these drying stresses by measuring hygromechanical strains during the drying of Eucalyptus nitens boards. Small samples of Eucalyptus nitens wood were oriented in the radial and tangential directions and tested to determine the hygromechanical strains during the drying process. This experimental work consisted of cantilevered bending tests conducted under variable relative humidity conditions. Tests were performed in a conditioning chamber at 30 °C with an equilibrium moisture content ranging from 22 to 12% under four levels of stress: 0, 10, 20 and 30% of the rupture load. The strains were determined using strain gauges, and the total deflection was measured with a linear variable differential transformer. The results show that in hygromechanical strains during the drying of Eucalyptus nitens, both the surface deformation and mechano-sorption strain were found to be proportional to the applied stress and reached their maximum values in the tangential direction. The total deflection increased 0,18 mm/mm with a surface deformation of 0,20 mm/mm, and the mechano-sorptive strain provides a greater contribution with a value of 0,11 mm/mm, thus corresponding to 59% of the total deformation. In attempts to improve the drying schedules of Eucalyptus nitens to develop solid wood products, mechano-sorptive behavior may be applied to relieve collapse and drying stress.

Collapse is almost certain to occur in the industrial drying of Eucalyptus nitens and, as such this prevents the lumber manufacturing industry in Chile from producing commercial solid wood products from this species. This problem is still unsolved, and different studies to reduce collapse are currently underway. In this exploratory study, shrinkage and collapse after drying of Eucalyptus nitens was measured for boards cut from different radial locations within the stem (core, transition, and outer wood from pith to bark) and having different annual ring orientations (flat-sawn and quarter-sawn). Though exploratory, the results appear to confirm that pieces that were cut from the center of the trees were less susceptible to collapse than pieces cut from the transition zone between the center and the periphery. On average, collapse in transition wood was approximately 50% higher than the collapse observed in wood cut from the central zone of the trees.

The occurrence of internal checks and their relationship with anatomical structure and basic density in three clones of Eucalyptus nitens plantation trees grown in the eighth region of Chile were studied. Two trees per clone were sampled. The number, radial location, and length of internal checks were determined in samples oven-dried at temperatures increasing from 50 to 100 C. Wood anatomical features including vessel frequency and diameter and annual growth ring width were measured by image analysis. Results show that internal checks were greater for clones with lower basic density. Internal check frequency decreased with height in the tree and increased from pith to bark. A low wood basic density was related to greater ring width and vessel frequency, which contributed to the development of internal checks.