Table 2.

Residual standard errors of fitted component ratio method models for the biomass components and for the combination of models and predictors.

Predictor × model	Biomass component
	Stem	Branch	Twig
Dbh
Nonlinear	0.0934/***	0.0923/***	0.0290/*
Linear	0.0658/***	0.0711/***	0.0243/***
dbh2
Nonlinear	0.1029/**	0.1109/**	0.0315/ns
Linear	0.0640/***	0.0716/***	0.0258/*
dbh2·ht
Nonlinear	0.1054/**	0.1157/**	0.0323/ns
Linear	0.0784/**	0.0858/**	0.0263/*

The biomass components are main stem, large branch, and twig. The two models are nonlinear and linear SUR. The three predictors are dbh, dbh², and dbh²·ht. RSE is residual standard error. The p-values of the estimated parameter β₁ in the fitted Component Ratio Method models (Eqs. 1 and 2) are represented by asterisk next to the reported RSEs: ns (p > 0.05), * (p ≤ 0.05), ** (p ≤ 0.01), *** (p ≤ 0.001), **** (p ≤ 0.0001).