The aim of this report is to study the intra species variability of Tetraclinis articulata originated from Morocco, because no data in the literature related to wood quality variability of this species.

Intra species variability and inter stans variability of Tetraclinis articulata was studied with ultrasonic and X ray microdensitometric techniques. The specimens were increment cores of 5mm diameter bored from forest trees at breast height.

For laboratory routine measurements the increment cores were conditioned at 12% moisture content. The age of the studied trees ranges between 42 and 81 years. Populations belong to the high mountainous vegetation zone, altitude between 920m and 1060m in Morocco.

Ultrasonic velocities of longitudinal and shear waves were used for the measurement of the stiffnesses. Panametrics ultrasonic equipment was used with transducers of 1 MHz frequency.

Significant correlations were established between shrinkage coefficients and annual ring characteristics. Intra species variability, studied with principal component analysis is explained by 61% with ultrasonic velocities, when only ultrasonic data were considered. Inter stand variability studied with X ray microdensitometric components as a function of age was explained by 78%, when only microdensitometric data were considered.

This study demonstrated that nondestructive techniques as ultrasonics and X ray microdensitometry on increment cores are very useful tools for the study of the variability of forest populations.