Predictor Importance Values for red spruce (Picea rubens)

Predictor Name	Importance Score	Rank
Annual precipitation (mm)	20.42	1
Mean May-September precipitation (mm)	15.54	19
Mean annual temperature (°C)	11.71	34
Mean May-September temperature (°C)	10.53	36
Mean temperature of coldest month (°C)	10.34	37
Mean temperature of warmest month (°C)	14.05	26
Annual aridity index	18.63	3
Minimum elevation	17.17	10
Maximum elevation	16.84	12
Average elevation	16.3	14
Median elevation	16.02	16
Range of elevation	16.76	13
Elevation coefficient ofvariation	18.52	5
Elevation standard deviation	17.94	6
Annual daylength coefficient of variation	8.98	38
Total available water capacity (cm, to 150 cm)	15.29	20
Total available water supply (cm, to 150 cm)	16.88	11
Depth to water table (cm)	17.19	9
Soil permeability rate (cm/hr)	15.74	18
Soil calcium carbonate (% by weight)	19.26	2
Soil cation-exchange capacity	13.7	27
Soil pH	12.23	31
Soil bulk density (g/cm3)	12.04	32
Organic matter content (% by weight)	12.78	29
Potential soil productivity	15.28	21
Soil erodibility factor, rock fragment free	10.77	35
Soil erosion by wind (tons/acre/year)	16.25	15
Percent soil passing sieve No. 10 (coarse)	17.42	8
Percent soil passing sieve No. 200 (fine)	14.59	23
Percent clay (< 0.002 mm size)	11.96	33
Percent sand (< 0.002 mm size)	14.11	25
Percent silt (< 0.002 mm size)	15.1	22
Percent of texture clayey	7.11	41
Percent of texture loamy	14.27	24
Percent of texture sandy	15.95	17
Percent of texture other	17.77	7
Alfisol (%)	13.43	28
Aridisol (%)	1.06	45
Entisol (%)	7.31	40
Histosol (%)	7.74	39
Inceptisol (%)	18.61	4
Mollisol (%)	7.11	42
Spodosol (%)	12.77	30
Ultisol (%)	6.04	43
Vertisol (%)	1.55	44