Official Journal of the Japan Wood Research Society
Table 5 Downgrading factors in the visual grading of lumber
From: Bending properties of dimension lumber produced from Siberian larch (Larix sibirica) in Mongolia
Factor | Quantity of downgraded lumber in each grade (%) | |||
|---|---|---|---|---|
SS | No. 1 | No. 2 | No. 3 | |
Knot | 28.4 | 20.5 | 16.8 | 8.4 |
ARW | 0.0 | 0.0 | 0.0 | 0.0 |
Wane | 15.3 | 15.3 | 10.0 | 8.9 |
Fiber orientation | 0.0 | 0.0 | 0.0 | 0.0 |
Crack | 0.0 | 0.0 | 0.0 | 0.0 |
Crook | 2.6 | 2.6 | 0.0 | 0.0 |
Bow | 2.1 | 2.1 | 1.1 | 0.0 |
Twist | 10.0 | 10.0 | 4.2 | 2.1 |