Estimativa da idade de segregação do lenho juvenil e adulto para Platanus x acerifolia (Ait.) Willd.

Abstract

This study determined the maturation age of Platanus x acerifolia (Ait.) Willd., through anatomical characteristics of the wood by means of the segregation of the juvenile-mature wood. Three adult trees were elected, of appropriate trunk and with diameter larger than at 40 cm (48, 41 and 46 cm) the 1.30 m of height. Discs with 2 cm of thickness at 0.1 m of height of the trunk were used. From each disc it was removed a central part of 2 cm of width, that was divided at the pith in samples “A” and “B”. Only one sample was selected and the initial wood of each growth ring was separated for maceration (method of Jeffrey). Departing from the pith, the length, diameter and the lumen of thirty staple fibres in each growth ring were measured. The thickness of the walls of fibers was taken as the half of the difference of the diameter of the fiber and the lumen. The segregation of the two types of wood was defined by the radial variation (pith-bark) of the anatomical characteristics (length, diameter, width of the lumen and thickness of the wall of fibers), through two simple linear regressions. The results indicate that the fiber length is the best characteristic for defining the segregation age. The age of segregation of juvenile-mature wood was defined as 14 years-old. In turn, the anatomical parameters, diameter of fibers, width of the lumen and thickness of the wall of fibers were found inadequate for estimating the age of segregation.