Least squares (LS) means (standard error) of normalized withdrawal resistance (NWR) (kN) of paper birch and sugar maple classified by (a) shank diameter (mm) and (b) thread length (mm) nested within shank diameter.
| (a) | (b) | ||||
|---|---|---|---|---|---|
| Shank Diameter | n | NWRzy | Thread Length | n | NWRx |
| 6.4 | 35 | 5.12 (0.36)a | 12.7 | 11 | 2.68 (0.43)a |
| 25.4 | 14 | 6.02 (0.38)b | |||
| 31.8 | 10 | 6.65 (0.48)c | |||
| 9.5 | 31 | 7.08 (0.38)b | 12.7 | 8 | 2.99 (0.51)a |
| 25.4 | 14 | 7.55 (0.38)b | |||
| 31.8 | 9 | 10.7 (0.48)c | |||
| 12.7 | 21 | 20.9 (0.43)c | 25.0 | 8 | 11.2 (0.53)a |
| 50.0 | 8 | 22.1 (0.53)b | |||
| 75.0 | 5 | 26.4 (0.66)c | |||
↵zNWR = PMAX/G1.35
↵yFor each shank diameter, LS means followed by the same letter were not significantly different (p > 0.0001) by Tukey’s HSD test.
↵xLS means for each level of thread length within each year followed by the same letter were not significantly different (p > 0.0001) by Tukey’s HSD test.