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Table 4 Coefficients with standard error of bivariate linear regression model (Eq. 1a for plant groups and Eq. 1b for total herb layer) between total above-ground biomass and percentage cover and elevation for plant groups and herb layer total on subplots, and explained variation (R2), Pearson product-moment correlation coefficient (Cor.coeff) and root mean squared error (RMSE). See Table 2 for sample size. Note that for modeling, percent cover of plant group is transformed using the natural logarithm, total herb layer cover is not transformed

From: Extending harmonized national forest inventory herb layer vegetation cover observations to derive comprehensive biomass estimates

Plant groupβ0 (Intercept)β1 (Percent Cover)β2 (Elevation)Adj. R2Cor.coeffRMSE (g·m−2)
Small herbs−0.5935310 *** (0.1274447)0.9039098 *** (0.0387518)0.0003887 *** (0.0001068)0.63 ***0.63 ***10.1
Tall herbs−0.3404689 (0.2858600)1.0773257 *** (0.0624539)0.0002557 (0.0002246)0.75 ***0.81 ***25.1
Grasses−0.1751947 (0.1818310)1.1453724 *** (0.0481618)0.00006194 ° (0.0001502)0.79 ***0.91 ***28.5
Sedges−0.1314442 (0.1536686)1.1004399 *** (0.0432052)0.0003158 * (0.0001321)0.77 ***0.68 ***24.2
Ferns−0.6882659 *** (0.1569825)1.1599828 *** (0.0390035)0.0001060 (0.0001206)0.84 ***0.83 ***23.8
Shrubs−0.8868706 *** (0.1464385)1.1755751 *** (0.0321635)0.0009174 *** (0.0001047)0.86 ***0.77 ***88.9
Shrubs leaves1− 0.54936569 * (0.27448296)0.94944646 *** (0.06683793)0.00004201 (0.00019741)0.75 ***0.83 ***10.1
Total, incl. Woody parts of shrubs0.98555045 *** (0.09465661)0.04150483 *** (0.00106115)0.00061034 *** (0.00008286)0.80 ***0.72 ***84.4
Total, excl. Woody parts of shrubs21.0841536 *** (0.1165718)0.0414646 *** (0.0014661)0.0002700 * (0.0001085)0.76 ***0.88 ***29.3
  1. Significance codes: 0 ‘***’, 0.001 ‘**’, 0.01 ‘*’, 0.05 °
  2. 1subsample of 68 subplots with measured woody and non-woody shrub biomass from the total 218 subplots with shrub cover
  3. 2subsample of 255 subplots without shrub occurrence (N = 187) as well as subplots with measured woody and non-woody shrub biomass (n = 68) but excluding the woody parts