A METHOD TO CHARACTERIZE IRREGULARITY IN THE CROSS-SECTIONAL FORM OF A STEM AND ITS EVOLUTION WITH TIME

The section perpendicular to the stem axis (SPSA) is often considered to be a perfect or almost perfect disk, although in fact this case is exceptional. The aim of this study was to characterize the eccentricity of SPSA by estimating its geometric center and its evolution with time. Eccentricity includes: eccentricity itself, ie no concordance between the geometric center of SPSA and the pith; flattening of the SPSA due to a greater increment in a given direction. Eccentricity is characterized by identifying several radial increments to vectors and the evolution of their sum. It is therefore possible to characterize eccentricity resulting from each year of growth and the evolution of the geometric center of SPSA from the beginning. It is also possible to link observations made at the same height for different trees, at different heights for a given tree and for trees with different vigors. Flattening can be accurately characterized by diameters passing through the pith if the number of radii is equal to at least 16.