Asymmetry of wood cross-sections. Definitions, methodology, and case studyon Norway-spruce

This study makes a revue of different definitions used to characterise the asymmetry of transverse stem sections. When the shape is described by inter section with 2n radii tone every 180/n degrees), the centre of mass of the points, the surface, and the shape can be defined. These points depend on t he number and the orientation of the radii. Their use for calculating eccen tricity (vector between the pith and the centre of the cross-section) or el lipticity (ratio between the largest diameter to its perpendicular) is test ed in various cases. An example is given for simple geometric shapes (circl e, ellipse) and for 168 Norway spruce cross-sections. (C) Inra/Elsevier, Pa ris.