Table 3 Site index model performance for Norway spruce

Estimate

Standard error

T statistics

p value

Intercept

3.473

0.005

633.864

< 2 × 10⁻¹⁶

country factor (Germany)

0.029

0.006

4.749

2.12 × 10⁻⁶

edf

Ref. df

F statistics

p value

s(T_5to9)

4.943

6.077

87.48

< 2 × 10⁻¹⁶

s(T1)

6.058

7.131

14.28

< 2 × 10⁻¹⁶

s(P)

7.906

8.667

12.94

< 2 × 10⁻¹⁶

Adjusted R²

0.191

Deviance explained

19.6%