Means (SEs in parentheses) for breaking stress and diameter ratio by type and form of attachment, failure mode, and the presence of included bark (IB)z.
| Type | N | Stress (MPa) | Diameter ratioy | Formx | N | Stress (MPa) | Diameter ratio | IB | N | Stress (MPa) | Diameter ratio | Modew | N | Stress (MPa) | Diameter ratio | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Red maple | Trunk–branch | 58 | 60.6 (2.10) a | 0.47 (0.016) a | U | 71 | 52.5 (2.43) a | 0.58 (0.025) a | No | 68 | 53.2 (2.47) a | 0.58 (0.116) a | BS | 51 | 62.2 (2.26) a | 0.45 (0.016) au |
| Branch–branch | 8 | 38.5 (4.30) b | 0.84 (0.030) b | V | 18 | 33.6 (5.24) b | 0.68 (0.050) a | Yes | 21 | 34.1 (5.32) b | 0.68 (0.106) a | EB | 16 | 40.8 (3.65) b | 0.72 (0.033) bu | |
| Codominants | 23 | 22.4 (2.23) c | 0.86 (0.019) b | FS | 22 | 23.3 (2.17) c | 0.88(0.016) cu | |||||||||
| Callery pear | Trunk–branch | 71 | 71.3 (2.43) au | 0.61 (0.015) a | U | 105 | N/Av | N/A | No | 105 | N/A | N/A | BS | 54 | 75.3 (2.87) a | 0.57 (0.014) a |
| Branch–branch | 6 | 45.9 (6.30) bu | 0.90 (0.034) b | V | 1 | N/A | N/A | Yes | 1 | N/A | N/A | EB | 36 | 47.2 (2.65) b | 0.82 (0.016) b | |
| Codominants | 29 | 32.1 (2.12) bu | 0.89 (0.016) b | FS | 16 | 31.2 (3.36) c | 0.91 (0.017) c | |||||||||
| Sawtooth oak | Trunk–branch | 59 | 104 (4.26) a | 0.53 (0.018) au | U | 56 | 100 (4.96) a | 0.57 (0.022) a | No | 39 | 104 (5.15) a | 0.56 (0.086) a | BS | 51 | 105 (4.56) a | 0.57 (0.019) a |
| Branch–branch | 10 | 55.0 (7.03) b | 0.85 (0.045) bu | V | 31 | 56.1 (5.38) b | 0.76 (0.036) b | Yes | 48 | 68.49 (6.57) b | 0.71 (0.098) b | EB | 14 | 56.8 (5.63) bt | 0.79 (0.038) bt | |
| Codominants | 18 | 36.7 (2.82) b | 0.87 (0.015) buv | FS | 15 | 34.0 (3.45) bt | 0.89 (0.014) bt |
↵zWithin each species, read down the column; means followed by the same letter are not significantly different (P > 0.05) by Tukey’s honestly significant difference test.
↵yInside-bark branch diameter/trunk diameter at the attachment.
↵xForm refers to the presence (u-shaped) or absence (v-shaped) of a branch bark ridge.
↵wBall and socket (BS), embedded bark (EB), and flat surface (FS).
↵vTest was not conducted as a result of insufficient v-shaped attachments and attachments with included bark.
↵uWelch’s analysis of variance was used because variance was nonhomogeneous among categories.
↵tFor these comparisons, P < 0.10.