Predictor Importance Values for bigtooth aspen (Populus grandidentata)

Predictor Name	Importance Score	Rank
Annual precipitation (mm)	20.4	16
Mean May-September precipitation (mm)	20.98	13
Mean annual temperature (°C)	19.95	19
Mean May-September temperature (°C)	19.21	22
Mean temperature of coldest month (°C)	19.77	20
Mean temperature of warmest month (°C)	22.12	8
Annual aridity index	14.84	38
Minimum elevation	24.42	3
Maximum elevation	20.59	15
Average elevation	16.09	35
Median elevation	17.6	31
Range of elevation	22.12	9
Elevation coefficient ofvariation	24.55	2
Elevation standard deviation	24.18	4
Annual daylength coefficient of variation	17.91	29
Total available water capacity (cm, to 150 cm)	19	23
Total available water supply (cm, to 150 cm)	17.65	30
Depth to water table (cm)	30.1	1
Soil permeability rate (cm/hr)	21.4	10
Soil calcium carbonate (% by weight)	18.69	25
Soil cation-exchange capacity	20.76	14
Soil pH	19.34	21
Soil bulk density (g/cm3)	23.47	5
Organic matter content (% by weight)	14.85	37
Potential soil productivity	21.12	12
Soil erodibility factor, rock fragment free	14.94	36
Soil erosion by wind (tons/acre/year)	18.08	28
Percent soil passing sieve No. 10 (coarse)	22.33	7
Percent soil passing sieve No. 200 (fine)	18.85	24
Percent clay (< 0.002 mm size)	18.4	27
Percent sand (< 0.002 mm size)	16.35	34
Percent silt (< 0.002 mm size)	20.2	18
Percent of texture clayey	14.83	39
Percent of texture loamy	17.47	32
Percent of texture sandy	21.24	11
Percent of texture other	7.74	42
Alfisol (%)	18.63	26
Aridisol (%)	0.52	45
Entisol (%)	6.21	43
Histosol (%)	11.98	40
Inceptisol (%)	20.35	17
Mollisol (%)	22.34	6
Spodosol (%)	8.09	41
Ultisol (%)	16.5	33
Vertisol (%)	5.55	44