Table 6. Parameters, standard errors, and performance metrics of biomass allometric equations based on the power function model for the fern group by independent variables.

Independent variable	Parameters			SEE^a	Adjusted R²	RMSE^b	MBE^c
Independent variable	α	β₁	β₂	SEE^a	Adjusted R²	RMSE^b	MBE^c
Nstem^d	2.3453	0.5762	-	1.2350	0.4195	7.6755	3.8132
Lstem^e	0.0037	2.0825	-	0.7115	0.3475	8.1375	−0.2441
H^f	0.4815	0.8695	-	1.0920	−0.0721	10.4313	2.5942
NstemㆍLstem	0.0517	0.9297	-	0.8780	0.5364	6.8597	3.2699
NstemㆍH	0.4593	0.5753	-	1.0570	0.4898	7.1961	2.9820
Nstem, Lstem	0.0019	0.5177	2.0404	0.5496	0.7487	4.8521	0.4955
Nstem, H	0.3526	0.3872	0.7702	1.0780	0.2391	8.4430	3.1802

SEE: Standard error of estimate
RMSE: Root mean squared error
MBE: Mean bias error
Nstem: Number of stems
Lstem: Length of main stem
H: Height.