Application of the Fractometer for crushing strength: Juvenile-mature wood demarcation in Taiwania (Taiwania cryptomerioids Hay)

The Fractometer is a device that breaks a radial increment core along the fiber for the measurement of crushing strength which is a direct wood quality indicator for structural lumber. In this study, the crushing strength of Taiwania (Taiwania cryptomerioides Hay) trees using the Fractometer was investigated and the data were used to determine the position of demarcation between juvenile and mature wood. Segmented regression and variance component analysis were used to estimate the demarcation position. Upon increasing the distance from the age, the crushing strength of juvenile wood has been improved. Within-tree variations in wood properties are greater than tree-to-tree variations. In this experiment, the position of demarcation between juvenile and mature wood occurred at an approximate distance of 10.8 cm to 13.2 cm from the pith that was about 18-20 yeas of cambium age.