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Official Journal of the Japan Wood Research Society

Journal of Wood Science Cover Image

Table 5 Downgrading factors in the visual grading of lumber

From: Bending properties of dimension lumber produced from Siberian larch (Larix sibirica) in Mongolia

FactorQuantity of downgraded lumber in each grade (%)
SSNo. 1No. 2No. 3
Knot28.420.516.88.4
ARW0.00.00.00.0
Wane15.315.310.08.9
Fiber orientation0.00.00.00.0
Crack0.00.00.00.0
Crook2.62.60.00.0
Bow2.12.11.10.0
Twist10.010.04.22.1
  1. Mean values were calculated from the ratio of the lumber downgraded to total lumber. Total lumber = 190
  2. ARW annual ring width, SS select structural