Predictor Importance Values for eastern cottonwood (Populus deltoides)

Predictor Name	Importance Score	Rank
Annual precipitation (mm)	13.39	34
Mean May-September precipitation (mm)	21.47	6
Mean annual temperature (°C)	18.96	14
Mean May-September temperature (°C)	18.1	21
Mean temperature of coldest month (°C)	19.52	11
Mean temperature of warmest month (°C)	14.91	29
Annual aridity index	21.7	5
Minimum elevation	17.52	25
Maximum elevation	12.91	37
Average elevation	18.87	16
Median elevation	18.29	19
Range of elevation	18.67	18
Elevation coefficient ofvariation	20.17	7
Elevation standard deviation	24.38	2
Annual daylength coefficient of variation	19.74	10
Total available water capacity (cm, to 150 cm)	15.9	27
Total available water supply (cm, to 150 cm)	17.82	23
Depth to water table (cm)	24.08	3
Soil permeability rate (cm/hr)	24.94	1
Soil calcium carbonate (% by weight)	14.88	30
Soil cation-exchange capacity	14.25	32
Soil pH	19.31	12
Soil bulk density (g/cm3)	23.33	4
Organic matter content (% by weight)	20.16	8
Potential soil productivity	19	13
Soil erodibility factor, rock fragment free	17.94	22
Soil erosion by wind (tons/acre/year)	18.87	15
Percent soil passing sieve No. 10 (coarse)	18.17	20
Percent soil passing sieve No. 200 (fine)	10.77	40
Percent clay (< 0.002 mm size)	17.57	24
Percent sand (< 0.002 mm size)	10.23	42
Percent silt (< 0.002 mm size)	13.82	33
Percent of texture clayey	18.67	17
Percent of texture loamy	13.18	35
Percent of texture sandy	15.57	28
Percent of texture other	12.6	39
Alfisol (%)	14.63	31
Aridisol (%)	1.19	45
Entisol (%)	10.42	41
Histosol (%)	13	36
Inceptisol (%)	19.84	9
Mollisol (%)	17.2	26
Spodosol (%)	8.86	43
Ultisol (%)	12.71	38
Vertisol (%)	8.24	44