The Position and Shape of Internal Checks in Sugi (Cryptomeria japonica) Boxed-heart Square Timber Dried High-temperature

In this study, the position and shape of internal checks in boxed-heart square timber were analyzed to acquire basic knowledge for internal checks caused by high-temperature drying. Sugi (Cryptomeria japonica) boxed-heart square timbers with a cross-sectional dimension of 105×105 mm supplied from 9 prefectures in Japan were used. The timbers were dried at high temperatures. The 16947 internal checks were extracted from 978 transverse-sectional images containing internal checks. Internal checks with large areas and lengths were unevenly distributed near the diagonal of the square timber. This result supports the experience knowledge. The method was considered proper for approximating the internal check as a diamond when calculating the area from the width and length.