According to elastic modulus of bending strength, ratio of knot and diameter, grain slope, yearly ring width and the wood defects of crackle, rot, discor, determinating indexes of board grade of small diameter larch.

• 根据抗弯弹性模量、节径比、纹理斜度、年轮宽度和裂纹、腐朽、变色等木材缺陷,确定小径落叶松层板等级。