Table 2 Linear model of intra-tree wood density variation according to the three factors studied
Factors | Parameter | Estimate | Std. error | t value | Pr(>|t|) | |
|---|---|---|---|---|---|---|
Tree diameter | (Intercept) | 0.670397 | 0.013347 | 50.23 | <2e-16 | *** |
Distance to pith Dp | 0.007174 | 0.003025 | 2.371 | 0.0179 | * | |
Diameter | ||||||
Small diameter | 0.021917 | 0.023336 | 0.939 | 0.3479 | – | |
Interaction Diameter × Dp | ||||||
Small diameter × Dp | −0.004962 | 0.008087 | −0.614 | 0.5397 | – | |
Residual standard error: 0.1556 Multiple R-squared: 0.006677, Adjusted R-squared: 0.03171 F-statistic: 1.904, p value: 0.1273 P values for Diameter and Diameter × Dp test are for significant differences relative to “Big Diameter” R 2 (model) = 1.27 %, R 2 (Diameter) = 0.0003 %, R 2 (Dp) = 0.96 %, R 2 (Diameter x Dp) = 0.31 % | ||||||
Light requirement | (Intercept) | 0.61 | 0.03 | 17.80 | <2e−16 | *** |
Distance to pith Dp | 0.004 | 0.01 | 0.47 | 0.64 | – | |
Light requirement | ||||||
Pioneer light demander | 0.03 | 0.04 | 0.90 | 0.37 | – | |
Semi-shade-tolerant | 0.14 | 0.04 | 3.64 | 0.00 | *** | |
Interaction: Light requirement × Dp | ||||||
Pioneer light demander × Dp | 0.002 | 0.01 | 0.20 | 0.84 | – | |
Semi-shade-tolerant × Dp | −0.001 | 0.01 | −0.10 | 0.92 | – | |
Residual standard error: 0.1509 Multiple R-squared: 0.1064, Adjusted R-squared: 0.1007 F-statistic: 18.69, p value: <2.2e−16 P values for Light requirement and Light requirement × Dp test are for significant differences relative to “Nomad light demander” R 2 (model) = 11.4 %, R 2 (Light requirement) = 10.2 %, R 2 (Light requirement) = 0.8 %, R 2 (Light requirement × Dp) = 0.4 % | ||||||
Soil type | (Intercept) | 0.41 | 0.06 | 6.49 | <0.001 | *** |
Distance to pith Dp | 0.004 | 0.02 | 0.25 | 0.80 | – | |
Soil type | ||||||
Xanthic ferralsol | 0.28 | 0.06 | 4.35 | <0.001 | *** | |
Orthic ferralsol | 0.28 | 0.07 | 4.26 | <0.001 | *** | |
Acric and xanthic ferralsol | 0.28 | 0.07 | 3.93 | <0.001 | *** | |
Entisols | 0.16 | 0.10 | 1.63 | 0.10 | – | |
Interaction: Soil type × Dp | ||||||
Xanthic ferralsol × Dp | 0.002 | 0.02 | 0.12 | 0.91 | – | |
Orthic ferralsol × Dp | −0.01 | 0.02 | −0.41 | 0.68 | – | |
Acric and xanthic ferralsol × Dp | 0.01 | 0.02 | 0.39 | 0.70 | – | |
Entisols × Dp | 0.01 | 0.03 | 0.38 | 0.71 | – | |
Residual standard error: 0.1475 Multiple R-squared: 0.1141, Adjusted R-squared: 0.1046 F-statistic: 12.07, p value: <2.2e−16 P values for Soil type and Soil type × Dp test are for significant differences relative to “Soils of lowland complex” R 2 (model) = 12.5 %, R 2 (Soil type) = 10.62 %, R 2 (Dp) = 0.78 %, R 2 (Soil type × Dp) = 1.08 % | ||||||