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Table 4 Model of the productivity (5-years aboveground biomass increment, Mg·ha−1·y−1) as a function of the dominant height, the stem density, the stand age and the forest treatment, analysed for production forest only before harvest

From: Effects of forest management on biomass stocks in Romanian beech forests

Parameter Estimate std error t value Pr(>|t|)
Model 3: Productivity = f (treatment, dominant height, age, stem density)
N = 1530, RMSE = 1.851, R2 = 0.647
Intercept 2.056 0.307 6.694 3.04e–11
Treatment: Shelterwood −0.013 0.111 −0.120 0.904
Aboveground biomass 0.016 4.9e–04 32.252 < 2e–16
Dominant height 0.009 1.1e–03 5.184 4.77e–16
Stem density 0.001 8.9e–05 16.171 < 2e–16
Stand age −0.038 3.1e–03 −12.388 < 2e–16
Model 4: Productivity = f (forest management type, age, stem density, removal)
N = 1530, RMSE = 1.847, R2 = 0.647
Intercept 2.042 0.308 6.637 0.00258 **
Treatment: Shelterwood −0.018 0.111 −0.158 0.874
Aboveground biomass 0.016 5.1e–04 31.759 < 2e–16 ***
Dominant height 0.009 1.1e–03 8.118 3.86e–07 ***
Stem density 0.001 8.9e–05 16.190 < 2e–16 ***
Stand age −0.038 0.111 −12.394 < 2e–16 ***
Biomass removed 0.002 0.002 0.825 0.410