Predictor Importance Values for willow oak (Quercus phellos)

Predictor Name	Importance Score	Rank
Annual precipitation (mm)	13.36	34
Mean May-September precipitation (mm)	19.62	6
Mean annual temperature (°C)	15.68	25
Mean May-September temperature (°C)	17.71	14
Mean temperature of coldest month (°C)	21.06	3
Mean temperature of warmest month (°C)	19.22	8
Annual aridity index	15.67	26
Minimum elevation	19.44	7
Maximum elevation	9.78	42
Average elevation	17.68	15
Median elevation	16.3	19
Range of elevation	10.57	39
Elevation coefficient ofvariation	15.8	24
Elevation standard deviation	18	10
Annual daylength coefficient of variation	20.68	4
Total available water capacity (cm, to 150 cm)	11.07	36
Total available water supply (cm, to 150 cm)	17.83	13
Depth to water table (cm)	17.98	11
Soil permeability rate (cm/hr)	17.06	16
Soil calcium carbonate (% by weight)	18.66	9
Soil cation-exchange capacity	16.29	21
Soil pH	15.15	29
Soil bulk density (g/cm3)	16.12	23
Organic matter content (% by weight)	22.7	1
Potential soil productivity	13.97	32
Soil erodibility factor, rock fragment free	15.6	27
Soil erosion by wind (tons/acre/year)	10.15	40
Percent soil passing sieve No. 10 (coarse)	16.85	17
Percent soil passing sieve No. 200 (fine)	14.46	31
Percent clay (< 0.002 mm size)	16.12	22
Percent sand (< 0.002 mm size)	11.25	35
Percent silt (< 0.002 mm size)	16.3	20
Percent of texture clayey	16.72	18
Percent of texture loamy	10.68	38
Percent of texture sandy	13.45	33
Percent of texture other	20.31	5
Alfisol (%)	17.96	12
Aridisol (%)	0	45
Entisol (%)	10.03	41
Histosol (%)	7.83	44
Inceptisol (%)	21.34	2
Mollisol (%)	15.3	28
Spodosol (%)	9.46	43
Ultisol (%)	14.74	30
Vertisol (%)	10.89	37