Site-Species Allometry Equation for Theobroma cacao L. Biomass Estimation in Agroforestry Systems of Cameroon

Table 3

Comparison of the models in this study with models commonly used to calculate the biomass of Theobroma cacao.

Authors	Model	RRMSE	Residual error (%)	Biomass (kg)
Aboveground biomass (AGB)
Chave et al. [18]	AGB (kg) = 0.0673 × (ρ D^2H)^0.976	0.339	−3.34	1618.65
Chave et al. [20]	AGB (kg) = 0.0509 × ρ D^2H	0.350	−15.273	1440.26
Somarriba et al. [22]	Log AGB (kg) = (−1.684 + 2.158 × log (d30) + 0.892 × log (alt))	0.82	−81.88	207.74
Model 1	ln B = −1.613 + 1.83 × ln (D)	0.198	3.47	1421.56
Model 6	ln B = −1.598 + 1.628 × ln (D) + 0.36 × ln (C)	0.190	3.21	1426.075
Observed biomass	—	—	—	1419.874
Belowground biomass (BGB)
IPCC [35]	BGB = Chave et al. [18] × 0.24	0.514	6.991	388.48
IPCC [35]	BGB = Chave et al. [20] × 0.24	0.468	−6.076	345.66
IPCC [35]	BGB = Somarriba et al. [22] × 0.24	0.81	−80.79	49.86
Model 1	ln B = −2.611 + 1.655 × ln (D)	0.316	7.92	315.47
Model 5	ln B = −2.564 + 0.64 × ln (D^2 × C)	0.294	7.20	316.84
Observed biomass	—	—	—	316.693
Total biomass (TB)
IPCC [35]	TGB = Chave et al. [18] × (1 + 0.24)	0.348	−2.877	2007.128
IPCC [35]	TGB = Chave et al. [20] × (1 + 0.24)	0.356	−14.834	1785.92
IPCC [35]	TGB = Somarriba et al. [22] × (1 + 0.24)	0.822	−80.67	257.60
Model 1	ln B = −1.297 + 1.79 × ln (D)	0.169	2.68	1732.12
Model 6	ln B = −1.278 + 1.57 × ln (D) + 0.37 × ln (C)	0.158	2.41	1738.01
Observed biomass	—	—	—	1736.567