Basic wood properties of Borneo ironwood (Eusideroxylon zwageri) planted in Sarawak, Malaysia

The aim of this study is to obtain the basic wood properties of planted Borneo ironwood (Eusideroxylon zwageri) from a plantation established about 80 years ago. Stem diameter at 1.3 m above the ground, tree height, and stress-wave velocity (SWV) of stem were measured on 36 planted E. zwageri trees. Later, core samples were collected from four trees whose measurements represented the average stem diameter of all the measured trees. Using the core samples, the moisture content (MC), basic density (BD), and compressive strength parallel to grain (CS) were measured. Dynamic Young’s modulus for longitudinal direction at green condition (E) was also calculated from SWV. There was no significant relationship between growth characteristics and SWV. Mean values of MC, BD, CS, and E were 37.2 %, 0.86 g/cm, 64.3 MPa, and 18.47 GPa, respectively. Significant differences among individual trees were found in MC, BD, and CS. In addition, radial variations were almost constant from bark side to pith side. The results indicate that longitudinal E is independent from growth characteristics, and that the E. zwageri wood tested in this study has uniform BD and CS in the radial direction.