Tensiones de crecimiento longitudinales en árboles de Eucalyptus nitens con dimensiones aserrables

Abstract

RESUMENEn el presente estudio se investigaron los niveles de tensiones de crecimiento longitudinales en árboles de Eucalyptus nitens con dimensiones aserrables. Junto con esto, se investigó la variación fustal de las tensiones de crecimiento longitudinales, del indicador de la tensión de crecimiento y del módulo de elasticidad de la madera en tensión, y se examinan las relaciones entre estas variables. Se escogieron aleatoriamente nueve árboles de una plantación de Eucalyptus nitens de 18 años de edad, crecida en la Región del Biobío, Chile. En cada árbol se midió el indicador de la tensión de crecimiento, en las exposiciones Norte, Sur, Este y Oeste, para una altura fija de 2 m, y al 33, 66 y 100% de la altura comercial del árbol, así como también, se determinó el módulo de elasticidad de la madera en tensión y las tensiones de crecimiento longitudinales en estas mismas exposiciones y alturas. El nivel medio de la tensiones de crecimiento longitudinales encontrado fue de 28,3 MPa. Las tensiones de crecimiento longitudinales, el indicador de la tensión de crecimiento y el módulo de elasticidad de la madera en tensión, variaron significativamente a través de las alturas y exposiciones en el fuste. Se encontró una alta influencia del indicador de la tensión de crecimiento en la estimación de los niveles de tensiones de crecimiento longitudinales.Palabras claves: Deformación de crecimiento, módulo de elasticidad, módulo de rigidez, propiedades de la madera, variabilidad de la madera. ABSTRACTIn this study, the levels of longitudinal growth stresses in Eucalyptus nitens trees with sawable dimensions were investigated. Furthermore, tree stem variations of the longitudinal growth stresses, growth stress indicator and modulus of elasticity in tension were also investigated, and the relationships between these variables were examined. Nine trees were randomly selected from a plantation of Eucalyptus nitens trees of 18 years old, grown at the Biobío region, Chile. Growth stress indicator were measured in each tree at North, South, East and West stem expositions, at 2 m height, and at 33, 66 and 100% of the tree merchantable height, in which modulus of elasticity in tension and longitudinal growth stresses were also determinated. The mean level of longitudinal growth stresses found was 28,3 MPa. All variables (longitudinal growth stresses, growth stress indicator and modulus of elasticity in tension) showed high variability through the expositions and heights in the tree stem. High influence of growth stress indicator on the estimation of longitudinal growth stresses was found.

Maturation Stress and Wood Properties of Poplar (Populus × euramericana cv. ‘Zhonglin46’) Tension Wood

“…Huang et al [46] also found no obvious relationship between height in tree and measured surface strains in the axial direction in Zelkova serrata erect trees. Other studies suggest that growth stresses do vary with sampling height, e.g., Omonte and Valenzuela [47] found that growth stress indicators at different heights were highly variable in the case of Eucalyptus nitens erect trees. Naghizadeh and Wessels [45] reported that growth strains decreased from 1.4 m to 11.4 m in Eucalyptus grandis-urophylla erect trees.…”

Distribution of Growth Stresses in Eucalyptus nitens Maiden Logs Immersed in Water

“…According to [9,10], once the trees have been cut down, the high growth stresses are released, causing three main defects: log end splitting after felling, warping and longitudinal splits in both logs and boards during the sawing process, and brittle heartwood resulting from excessive compressive stress, limiting the use of this wood.…”

Artificial intelligence to growth stresses predicting in Eucalyptus clones using dendrometric variables and wood density

“…The effect of high growth stress levels on a tree may result in cracks and twists in the logs and lumber (Gril et al 2017, Amer et al 2019. This parameter can also be a predictor of sawlog quality (Valencia et al 2011) in the alteration of the wood physical, mechanical (Diaz Bravo et al 2012, Omonte andValenzuela 2015), and anatomical properties (Kojima et al 2011, Li et al 2018.…”

“…The basic density is another variable that is easy to measure and correlates with many of the wood's technological properties. Several studies on the relationship between wood properties or dendrometric variables and LGS in trees have been carried out with simple correlations and traditional statistical models (Cardoso Junior et al 2005, Valencia et al 2011, Diaz Bravoet al 2012, Omonte and Valenzuela 2015, França et al 2017, Xavier et al 2018.…”