Table 4 Site index model performance for European beech

Estimate

Standard error

T statistics

p value

Intercept

3.228

0.030

106.4

< 2 × 10⁻¹⁶

Country factor (Germany)

0.131

0.009

15.0

< 2 × 10⁻¹⁶

edf

Ref. df

F statistics

p value

s(T_wq)

6.250

7.197

9.684

4.1 × 10⁻¹²

s(P_5to9)

2.743

3.048

24.544

9.07 × 10⁻¹⁶

s(elevation)

7.919

8.593

40.596

< 2 × 10⁻¹⁶

Adjusted R²

0.4013

Deviance explained

41.6%