An acceptable method of estimating timber strength has to be established to develop confidence in using as construction materials. Four timber species of different density classes namely Cotylelobium melanoxylon, Shorea albida, Palaquium folanigerum and Dacrydium pectinatum were used in this study. The nominal size of cross-section of 100mm by 100 mm and to a length of 2000 mm. A total of 157 specimens were tested in green condition. Four measuring methods of measuring modulus of elasticity namely E_fr, E_dwe, E_app and E_tru were compared and used to predict the bending strength of full size structural components. It was found that their coefficients of correlation were 0.83, 078, 0.82 and 0.80 respectively and significant at 1 % level. This showed that there were strong correlation between moduli of elasticity and bending strength as far timber species as concerned. This could be suggested that any of modulus of elasticity could be use as a nondestructive parameter in estimating the bending strength.

Density played an important role in determining the strength of timber. Hence a new method should be established as to predict basic density. A pilodyn wood tester was introduced as to study the correlation between penetration depth of the striker pin to the timber and their basic density. It was found that there was a strong correlation between basic density and penetration depth with coefficient of correlation 0.77 at 1 % significant level.