Abstract
We investigated the influence of external log quality on the presence of knots on the sawn faces through the sawing tests of medium diameter, normal quality sugi (Cryptomeria japonica D. Don) log.
When the log surface was divided into four log faces, the results showed a tendency for an increase in the appearance rate of clear sawn faces as the distance from the log face to the pith on the top end of the log increased. Except butt logs, the results also showed a tendency for an increase in the appearance rate of clear sawn faces as the distance from the log face to the pith on the butt end of the log increased. A proportionality was not seen between the distance from the log face to the position of maximum warp and the appearance rate of clear sawn faces. The appearance rate of clear sawn faces on the opening face with the sawing method whose opening face was decided by the most distant log face from the pith on the top end was about 10% higher than that with the conventional sawing method whose opening face was decided by the warp of the log.
Therefore, it was thought that the pith on the top end was the most effective index to predict the log face in which a clear sawn face was expected.
