Table 3.
Best fit models for estimating the percentage of “incomplete seed” damage, based on the sample of 192 Pinus strobiformis trees.
| Variable selection method | Machine learning algorithm | Independent variables | RMSE | MAE | R2 |
|---|---|---|---|---|---|
| ROC | brnn | DD5, GSP, WINP, SMRPB, Mnppm, dieback, Kppm, MgCEC | 0.115 | 0.090 | 0.342 |
| KWL | nnet | MTWM, SMRPB, dieback, GSP, %Sat, Znppm, Mnppm, FFP | 0.118 | 0.098 | 0.325 |
| KWE | avNNet | MMAX, FDAY, SMRPB, SPRP, dieback, shoot death, Slope, Znppm | 0.119 | 0.095 | 0.323 |
| PLS | lm | MAT, MMAX, EC, MAP, SMRPB, Pinus cooperi, MMIN, Nappm | 0.121 | 0.094 | 0.326 |
| KWE | rf | MMAX, FDAY, SMRPB, SPRP, dieback, shoot death, Slope, Znppm | 0.125 | 0.096 | 0.264 |
| PLS | mlpWeightDecay | MAT, MMAX, EC, MAP, SMRPB, Pinus cooperi, MMIN, Nappm | 0.141 | 0.110 | 0.022 |
ROC, Receiver Operating Characteristic; KWL, Kruskal Wallis selected with latitude; KWE, Kruskal Wallis selected with elevation; PLS, Partial Least Squares; brnn, Bayesian Regularized Neural Networks; nnet, Neural Network; avNNet, Model Averaged Neural Network; lm, linear regression; rf, Random Forest; mlpWeightDecay, Multi-Layer Perceptron; RMSE, Root-mean-square error; MAE, Mean Absolute Error; R2, Determination coefficient; DD5, Degree-days >5 degrees C (based on mean monthly temperature); GSP, Growing season precipitation (April to September); WINP, Winter precipitation: (nov+dec+jan+feb); SMRPB, Summer precipitation balance: (jul+aug+sep)/(apr+may+jun); Mnppm, manganese concentration in the soil (ppm); dieback,Cronartium ribicola damage measurement; Kppm, potassium concentration in the soil (ppm); MgCEC, proportion of magnesium in CEC (cation exchange capacity); MTWM, Mean temperature in the warmest month (degrees C); %Sat, Percent of water saturation; Znppm, zinc concentration in the soil (ppm); FFP, Length of the frost-free period (days); MAT, Mean annual temperature (degrees C); MMAX, Mean maximum temperature in the warmest month (degrees C); EC, Electrical conductivity (dS/m); MAP, Mean annual precipitation (mm); Pinus cooperi, frequency of occurrence of Pinus cooperi in the neighborhood; MMIN, Mean minimum temperature in the coldest month (degrees C); Nappm, sodium concentration in the soil (ppm); FDAY, Julian date of the first freezing date of autumn; SPRP, Spring precipitation: (apr+may); shoot death, Cronartium ribicola damage measurement; Slope, slope position (%).