The relationships among structure variables of larch forests in China

Forest Ecosystems

Table 1 The best regression model selected by forward stepwise regression for the structure variables of larch forests in China

Variable	df	F-value	p-value	SS (%)	R² of model
Stem density (stem∙ha⁻¹)					0.15
Latitude	1	27.91	< 0.01	15.43
Residuals	153			84.57
Height (m)					0.48
Forest type	10	11.68	< 0.01	42.91
Longitude	1	4.75	< 0.05	1.75
Latitude	1	2.21	0.14	0.81
Altitude	1	7.46	< 0.01	2.74
Residuals	141			51.79
DBH (cm)					0.37
Forest type	10	7.07	< 0.01	31.23
Longitude	1	8.57	< 0.01	3.79
Altitude	1	5.02	< 0.05	2.22
Residuals	142			62.76
Taper (cm∙m⁻¹)					0.74
Forest type	10	36.43	< 0.01	66.52
Longitude	1	1.45	0.23	0.26
Latitude	1	0.72	0.40	0.13
Altitude	1	40.25	< 0.01	7.35
Residuals	141			25.74

df, F-value and SS (%) are degree of freedom, F statistical value and percentage of sum squares explained, respectively