Within-tree variation regarding ultrasonic velocity, wood density and compressive strength of the eucalypt hybrid (Eucalyptus urophylla × E. pellita)

ABSTRACT

A variation study of the ultrasonic velocity (V_u), wood density (AD), and compressive strength (CS) within trees (longitudinal and radial) of the eucalypt hybrid uropellita (Eucalyptus urophylla × E. pellita) was carried out for the first time. V_u was measured in pith-to-bark strips collected from six stem height levels (0.5, 1.5, 2.5, 3.5, 4.5, and 5.5 m above the ground) in the longitudinal axis using air-coupled ultrasonic techniques, and AD and CS were measured for small clear specimens obtained from these strips. In general, V_u increased outwards from the pith with increasing stem height. The overall mean values of V_u, AD, and CS were 2872 m/s, 0.50 g/cm³, and 41.40 MPa, respectively. Within the stem, the radial position was highly significant (P < 0.001) for all traits, whereas the longitudinal variation was significant only for V_u but its contribution was small (approximately 9% of the total variation). V_u and AD had significant (P < 0.05) positive linear correlations with CS in both the radial position and combined radial positions. The best prediction of CS was obtained when V_u and AD were used together by calculating the dynamic modulus of elasticity (E_d).

KEYWORDS:

• Eucalypt hybrid uropellita
• ultrasonic velocity
• air-dry density
• compressive strength

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the Vietnam Ministry of Education and Training [grant number B2022-TNA-41].