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Table III
Allometric equations of heartwood ring number (HRN) against cambial age (CA, y) for the six tree species. The heartwood initiation age (HIA, y) is extrapolated from the equations. N and R2 are sample size and determination coefficient. The equations are all significant (P < 0.001).
| Tree species | N | CA range | Allometric equation | R 2 | HIA |
|---|---|---|---|---|---|
| Korean pine | 102 | 5–36 | HRN = 0.68CA − 3.11 | 0.910 | 4.6 |
| Dahurian larch | 131 | 5–43 | HRN = 0.86CA − 4.23 | 0.976 | 4.9 |
| Japanese elm | 116 | 5–112 | HRN = 0.98CA − 4.14 | 0.995 | 4.2 |
| Manchurian ash | 132 | 9–103 | HRN = 0.97CA − 8.22 | 0.984 | 8.5 |
| Manchurian walnut | 53 | 7–58 | HRN = 0.94CA − 5.04 | 0.997 | 5.4 |
| Amur cork-tree | 35 | 9–65 | HRN = 1.04CA − 6.07 | 0.999 | 5.8 |