Machine learning and geostatistical approaches for estimating aboveground biomass in Chinese subtropical forests

Forest Ecosystems

Table 5 Parameters of the theoretical semivariogram models of the residuals for the RFOK and RFCK models

Model parameter	Theoretical model	Nugget	Sill	Nugget/Sill ratio	Range (degree)	R²	RSS
1992_RFOK	Gaussian	9.95	27.19	0.366	0.618	0.921	80.90
1992_RFCK	Gaussian	8.11	12.42	0.653	0.653	0.923	52.15
2002_RFOK	Exponential	402.91	507.46	0.792	0.935	0.139	9865.00
2002_RFCK	Exponential	365.46	482.14	0.758	0.905	0.143	9217.00
2010_RFOK	Spherical	307.80	328.50	0.937	0.348	0.156	9364.00
2010_RFCK	Spherical	302.93	312.96	0.968	0.492	0.181	8124.50