Table 3 Cross-validation results for the 4 tested crown volume models. The cross-validation procedure was repeated 1000 times preserving 75% of the database for training models and 25% for testing, randomly extracted. The standard deviation within single runs is reported between brackets
From: Single-tree crown shape and crown volume models for Pinus nigra J. F. Arnold in central Italy
Crown portion | Fitted model | Var.explained | MAE | MARE |
|---|---|---|---|---|
ABOVE | Exponential | 80.0% (± 5.4%) | 20.32 (± 2.02) | 138.15% (± 31.4%) |
Linear | 76.8% (± 4.5%) | 18.31 (± 2.83) | 162.45% (± 34.5%) | |
Polynomial | 91.3% (± 3.1%) | 10.21 (± 2.11) | 59.08% (± 16.3%) | |
Power | 90.0% (± 4.4%) | 4.14 (± 0.63) | 12.51% (± 2.5%) | |
BELOW | Exponential | 70.3% (± 7.7%) | 21.36 (± 1.63) | 174.52% (± 29.2%) |
Linear | 76.3% (± 3.2%) | 15.70 (± 1.82) | 143.90% (± 25.8%) | |
Polynomial | 85.5% (± 4.6%) | 13.06 (± 2.36) | 57.54% (± 13.4%) | |
Power | 82.4% (± 4.2%) | 12.06 (± 0.85) | 32.16% (± 3.9%) |