Table 1.

Linear mixed models were used to evaluate the effects of climate, soil properties and location properties on the initial Na and Al concentration of leaf, branch and root litter.

Predictor	Index	Na			Al
		Leaf	Branch	Root	Leaf	Branch	Root
Climate	MAT (°C)	0.007**	0.004	0.004	0.003**	0.009*	0.002
	TMax (°C)	0.005	0.002	0.006	0.003	0.007*	0.007
	TMin (°C)	0.004**	0.002	0.002	0.002**	0.424	0.001
	MAP (mm)	0.001	0.001	0.001	0.001*	0.001	0.001
	WMP (mm)	0.001	0.001	0.001	0.001*	0.001	0.001
	DMP (mm)	-0.001	0.001	-0.006	0.001	0.007	0.001
Soil properties	TOC (%)	-0.004	-0.003	-0.001	-0.001	0.016	0.002
	SOC (%)	-0.014**	-0.049	-0.008	-0.001	0.068	0.001
	STN (%)	-0.354**	-0.198	-1.085	-0.039	0.847	0.263
	STP (%)	-0.246***	-0.443	0.091	0.005	0.019	-0.069
	Soil pH	0.014	0.021	0.042	-0.002	-0.085	-0.006
	BD (g/cm3)	0.122	0.236	0.212	0.035	-0.706	-0.108
	VWC (%)	-0.002	0.012	0.020*	0.001	0.005	0.004
Location	Slope (°)	-0.002	-0.007	-0.031	0.001	-0.010	-0.003
	Elevation (m)	0.001	0.001	0.000	0.001	0.001	0.001

We regarded each tested factor as a fixed effect and the study identity as a random effect. Estimates and p value are given, and bold indicates statistical significance. Asterisks indicate effects differences at *p < 0.05, **p < 0.01, ***p <0.001.

MAT, mean Annual mean temperature; TMax, mean Maximum temperature of the warmest month; TMin, mean Minimum temperature of the coldest month; MAP, mean Annual precipitation; WMP, mean Precipitation of the wettest month; DMP, mean Precipitation of the driest month; TOC, mean Total soil carbon; SOC, mean Soil organic carbon; STN, mean Total soil nitrogen (N); STP, mean Total soil phosphorus (P); Soil pH, mean soil pH; BD, mean Bulk density; VWC, mean volumetric water concentration at -33 KPa.