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Table 3 Parameter estimates for the BASE, GB99 and M3_HABH taper models

From: Use of upper stem diameters in a polynomial taper equation for New Zealand radiata pine: an evaluation

Parameter

Estimate

BASE model

Model GB99

Model M3_HABH

β 1

T-S

T-S

T-S

β 2

T-S

T-S

β 21

0.0929 (0.0130)

β 3

0.4125 (0.0189)

0.5502 (0.0053)

β 30

0.8213 (0.0351)

β 31

−0.2040 (0.0199)

γ 1

1.4420 (0.0061)

1.7149 (0.0440)

γ 10

0.9377 (0.0237)

γ 11

0.3522 (0.0169)

γ 2

16.6627 (2.4157)

14.5371 (0.6206)

2.1955 (0.1190)

γ 3

64.2933 (3.0251)

34.3438 (0.4982)

γ 31

1.3431 (0.0351)

  1. The standard errors of the parameter estimates are given in parentheses. For the BASE model, parameter β 1 is constrained to dbh, and for models M3_HABH and GB99, parameter β 1 is constrained to dbh and β 2 to the upper stem diameter (diameter at 6 m for the GB99 model). The estimates for the constrained parameters are tree-specific (T-S). The parameter estimates given were all statistically significant (p ≤ 0.0001). Residual correlation parameters are not included because they are not important for model prediction purposes