Table 4 Regression coefficients of the fixed effects (standard errors are shown in parentheses) and marginal (R²_m) and conditional R² (R²_c) for the best linear mixed-effects models of basal area increment for F. sylvatica, Q. petraea, and Q. pyrenaica, considering the 1994–2015 period

Intercept

2.611 (0.073)***

2.821 (0.094)***

2.355 (0.115)***

Annual DBH

0.275 (0.045)***

0.265 (0.060)***

Annual BA

− 0.298 (0.095)**

− 0.453 (0.077)***

Fraction of F. sylvatica

− 0.299 (0.103)**

− 0.464 (0.141)**

Fraction of Q. petraea

− 0.366 (0.134)**

Fraction of Q. pyrenaica

− 0.306 (0.108)**

− 0.570 (0.151)***

T _March

0.078 (0.016)***

P _April

0.064 (0.018)***

P _{from previous June to previous October}

0.077 (0.015)***

T _March × P _April

− 0.100 (0.027)***

P _{from April to July}

0.030 (0.007)***

0.041 (0.008)***

P _{from previous July to previous September}

0.037 (0.008)***

R²_m

0.307

0.381

0.365

R²_c

0.612

0.858

0.879