Predictor Importance Values for black willow (Salix nigra)

Predictor Name	Importance Score	Rank
Annual precipitation (mm)	14.81	33
Mean May-September precipitation (mm)	16.09	29
Mean annual temperature (°C)	17.9	24
Mean May-September temperature (°C)	13.58	37
Mean temperature of coldest month (°C)	16.38	28
Mean temperature of warmest month (°C)	19.79	12
Annual aridity index	14.2	35
Minimum elevation	8.2	43
Maximum elevation	11.94	40
Average elevation	14.29	34
Median elevation	18.01	23
Range of elevation	8.21	42
Elevation coefficient ofvariation	18.25	21
Elevation standard deviation	7.92	44
Annual daylength coefficient of variation	18.73	18
Total available water capacity (cm, to 150 cm)	19.98	11
Total available water supply (cm, to 150 cm)	18.61	20
Depth to water table (cm)	22.07	4
Soil permeability rate (cm/hr)	19.02	16
Soil calcium carbonate (% by weight)	19.19	14
Soil cation-exchange capacity	18.16	22
Soil pH	17.76	25
Soil bulk density (g/cm3)	23.45	2
Organic matter content (% by weight)	21.14	7
Potential soil productivity	20.51	9
Soil erodibility factor, rock fragment free	21.04	8
Soil erosion by wind (tons/acre/year)	18.73	19
Percent soil passing sieve No. 10 (coarse)	21.98	5
Percent soil passing sieve No. 200 (fine)	21.32	6
Percent clay (< 0.002 mm size)	15.5	32
Percent sand (< 0.002 mm size)	12.89	38
Percent silt (< 0.002 mm size)	15.82	30
Percent of texture clayey	15.61	31
Percent of texture loamy	19.64	13
Percent of texture sandy	18.94	17
Percent of texture other	20.5	10
Alfisol (%)	23.15	3
Aridisol (%)	1.6	45
Entisol (%)	19.07	15
Histosol (%)	14.05	36
Inceptisol (%)	28.11	1
Mollisol (%)	17.6	26
Spodosol (%)	11.29	41
Ultisol (%)	16.54	27
Vertisol (%)	12.61	39