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|