Table 3. Selected variables for the predictive nonlinear models of biophysical forest attributes (BFA) by approach and their respective model fit and error structure.
S BFA NEW approach REUSE approach FORECAST approach
Explanatory
variables a 		r2 RMSE% λ0 λ1 σεem Explanatory
variables a 		r2 RMSE% λ0 λ1 σεem Explanatory
variables a 		r2 RMSE% λ0 λ1 σεem
S1 Ho H90.F, D0.F 0.79 7.8 3.64 0.80 1.29 H80.F 0.90 6.7 1.81 0.90 1.13 H90.F 0.84 7.2 3.17 0.84 1.34
HL H90.L 0.86 7.5 2.19 0.85 1.04 H80.F 0.92 6.1 1.04 0.92 0.82 H80.F, D3.F, Hsd.L 0.89 6.5 2.00 0.89 1.09
N D4.F, H90.L 0.44 32.6 841 0.45 349 D2.F, D8.F 0.52 30 853 0.53 404 H60.F, D6.L 0.44 49.5 527 0.45 322
G D9.F, H10.L 0.76 20.3 6.09 0.78 5.11 Hmean.F, D0.L 0.93 12.1 1.38 0.94 3.02 H90.F, D9.L 0.70 23.5 9.79 0.71 6.91
V D9.F, H10.L 0.87 23.3 14.24 0.92 48.99 Hsd.F, H90.L, D0.L 0.97 10.7 6.60 0.97 19.90 H90.F, D9.L 0.79 26.2 59.70 0.80 71.77
AGB D9.F, H10.L 0.86 21.1 12.38 0.90 28.05 H90.L, D1.L 0.91 18.1 5.84 0.94 21.02 H90.F, D9.L 0.74 26.7 43.15 0.75 40.73
S2 Ho H90.F, D0.F 0.84 5.5 3.89 0.83 1.15 Hmax.L 0.84 6.9 2.96 0.83 1.10 H70.F, H30.L 0.89 5.7 1.87 0.90 1.02
HL H90.F, H10.L 0.89 5.0 2.34 0.88 0.94 H20.F, H80.F 0.91 5.5 1.55 0.90 0.83 H70.F 0.87 6.60 2.13 0.87 1.06
N H60.F, D1.F 0.62 34.2 324 0.65 273 H60.F, D0.F, D5.L 0.77 23.6 135 0.78 134 D0.F 0.49 32.6 297 0.50 141
G D1.F, D9.L 0.71 16.8 9.38 0.73 5.08 D0.F, H80.L 0.71 21.8 6.47 0.71 4.25 H90.F, D9.L 0.73 25.0 7.47 0.74 6.21
V H70.L, D0.L 0.83 18.0 55.82 0.83 54.69 H80.L, D0.L 0.84 20.8 30.08 0.83 34.29 H90.F, D9.L 0.81 26.1 42.15 0.82 57.01
AGB H90.L, D1.L 0.83 15.9 31.53 0.83 27.25 Hsd.F, H90.L, D0.L 0.83 20.9 16.42 0.84 20.08 H70.F 0.78 27.5 26.07 0.80 34.23
S3 Ho D0.F, D7.F, Hmean.L 0.90 6.3 1.77 0.90 1.11 Hmax.F 0.71 6.5 6.62 0.72 1.31 H90.L 0.80 5.9 4.37 0.80 1.19
HL Hcv.F, Hmean.L 0.94 4.7 1.06 0.94 0.76 Hmax.F, H40.L 0.72 6.8 5.75 0.72 1.21 H90.L, D6.L 0.91 5.2 1.70 0.91 0.96
N H50.F, D5.F, D5.L 0.70 28.6 179 0.70 149 H20.F, D5.F 0.60 21.6 305 0.62 144 H90.F, D6.L 0.46 45.3 622 0.45 336
G H60.L, D3.L 0.81 22.9 4.99 0.81 5.59 Hmax.F, D7.L 0.65 16.6 11.83 0.65 4.65 Hmax.F, D7.F 0.69 16.4 11.97 0.69 5.37
V Hmean.L, D3.L 0.86 23.2 36.30 0.84 47.22 Hmax.F, H10.F, D7.L 0.71 19.3 96.57 0.71 55.80 D6.F, H90.L 0.82 17.8 64.13 0.82 58.52
AGB Hmean.L, D3.L 0.85 22.8 19.07 0.85 27.01 Hmax.F, D7.L 0.69 18.8 61.34 0.68 30.19 Hmax.F, D6.F 0.77 16.9 45.60 0.78 30.85
S = Stratum. S1 = Young forest, S2 = Mature forest with Site index ≤ 11 m, S3 = Mature forest with Site index > 11 m. Biophysical forest attributes; Ho = Dominant height (m), HL = Lorey’s mean height (m), N = Stem number (ha–1), G = Basal area (m2 ha–1), V = Volume (m3 ha–1), AGB =Aboveground biomass (Mg ha–1). a See section 2.4.1 for variable description. r2 = pseudo R2. RMSE% = relative root mean square error. λ0, λ1, σεem = parameters from the error model equation.