From: Improving stem quality assessment based on national forest inventory data: an approach applied to Spanish forests
Crookedness quality (QC)
Single crook
Multiple crooks
1
 < 2 cm/m
Not allowed
2
 ≤ 2.6 cm/m
 ≤ 1 cm/m
3
Allowed
 ≤ 2 cm/m
4