| Model | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| α | −2101 | −23,940 | −13,848 | −13,454 | −1996 | 29,739 | 39,708 | 44,724 |
| m3/ha | 466 | 375 | 368 | 374 | 376 | 363 | 372 | 366 |
| p-value | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 |
| Ave. yield | 6239 | 5981 | 6421 | 5108 | 1596 | |||
| p-value | 0.000 | 0.000 | 0.000 | 0.000 | 0.207 | |||
| No. stands | −4781 | −4326 | −3992 | −3278 | −3218 | −2848 | ||
| p-value | 0.001 | 0.002 | 0.004 | 0.013 | 0.015 | 0.029 | ||
| Reg III | −9375 | −14,575 | −26,990 | −29,452 | −31,231 | |||
| p-value | 0.003 | 0.000 | 0.000 | 0.000 | 0.000 | |||
| Reg IV | −13,476 | −32,137 | −37,094 | −37,178 | ||||
| p-value | 0.002 | 0.000 | 0.000 | 0.000 | ||||
| Reg V | −30,535 | −35,959 | −34,434 | |||||
| p-value | 0.000 | 0.000 | 0.000 | |||||
| Prodarea | −97 | |||||||
| p-value | 0.008 | |||||||
| R2 (adj) | 48.65 | 57.89 | 60.31 | 62.22 | 64.11 | 67.81 | 67.69 | 68.88 |