Abstract

VELASQUEZ, Jesús et al. Axial and radial variation pattern in the specific gravity of the wood of erisma uncinatum warm. INCI [online]. 2009, vol.34, n.12, pp.873-879. ISSN 0378-1844.

The natural variability of wood is a product of its cellular heterogeneity, evidenced in its anatomy as well as in its chemical composition, which in turn are reflected upon its physical and mechanical properties. A characterization of the axial and radial variation pattern in the dry specific gravity was carried out on wood of the species Erisma uncinatum ("mureillo"), from a forest in the Guayana region, Venezuela. The evaluation was carried out using a sample of six trees. Samples were taken at three different height levels (1.30m, 30% and 60% of commercial height). The radial evaluation was performed on five equidistant points in a pith-bark radial direction (0, 25, 50, 75, 90%). The statistical analysis indicated that the variation between trees was not statistically significant compared to the effect of radial distance in each individual. The specific gravity of the wood presented a mean value of 0.52 ±0.7. The radial variation showed a positive linear increase from pith to bark (R²=0.68), with a 22% variation, evidencing a preliminary boundary between juvenile and adult wood, beginning at 50% of the direction of cellular radii. The axial variation decreases with tree height and is less consistent than the radial variation, barely 13%. The physiological age of the vascular cambium is an important factor that determines the variation in the specific gravity of Erisma uncinatum wood.

Keywords : Erisma uncinatum; Peso Específico de la Madera; Variabilidad de la Madera.