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Table 4 Diameter fit/prediction and volume prediction error statistics 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

Dimension Model Fitting data Split-validation data Independent-validation data
  MBdob (%) MABdob (%) RMSEdob (%) MBdob/v (%) MABdob/v  (%) RMSEdob/v (%) MBdob/v (%) MABdob/v  (%) RMSEdob/v (%)
Stem diameters BASE 0.143 4.254 5.802 0.696 4.313 5.788 1.603 5.060 7.052
GB99 −0.429 3.561 5.208 −0.174 3.529 5.110 1.005 4.291 6.136
M3_HABH 0.263 3.093 4.523 0.466 3.142 4.488 0.535 3.872 5.615
Total aboveground volume BASE     1.133 5.515 7.720 1.371 5.322 7.408
GB99     −1.316 3.768 5.247 0.525 4.683 6.372
M3_HABH     0.768 2.729 3.824 −0.816 2.810 3.937
Volume to 14-cm top diameter (pulpwood volume) BASE     0.784 5.328 7.553 0.707 5.092 6.989
GB99     −1.586 3.671 5.153 −0.003 4.430 6.056
M3_HABH     0.616 2.675 3.709 −1.232 2.863 4.140
Volume to 22-cm top diameter (sawtimber volume) BASE     0.884 5.123 7.402 0.129 4.718 6.514
GB99     −1.616 3.378 4.974 −0.472 4.038 5.697
M3_HABH     0.763 2.861 3.982 −1.592 2.994 4.457
  1. The percentages are based on the following overall means: (a) fitting data stem diameter means = 31.65 cm; (b) split-validation stem diameter means = 31.38 cm and tree volume mean = 2.528 m3 for total aboveground volume, 2.439 m3 for pulpwood volume and 2.310 m3 for sawtimber volume; and (c) independent-validation stem diameter means = 36.67 cm and volume mean = 3.649 m3 for total aboveground volume, 3.556 m3 for pulpwood volume and 3.429 m3 for sawtimber volume. The lowest MAB and RMSE values are shown in italics