Predictor Importance Values for sweet birch (Betula lenta)

Predictor Name	Importance Score	Rank
Annual precipitation (mm)	14.97	29
Mean May-September precipitation (mm)	21.43	7
Mean annual temperature (°C)	15.61	27
Mean May-September temperature (°C)	16.14	25
Mean temperature of coldest month (°C)	19.27	16
Mean temperature of warmest month (°C)	13.96	32
Annual aridity index	14.77	30
Minimum elevation	22.68	1
Maximum elevation	19.29	15
Average elevation	13.83	34
Median elevation	14.07	31
Range of elevation	22.63	2
Elevation coefficient ofvariation	17.89	20
Elevation standard deviation	17.47	21
Annual daylength coefficient of variation	21.86	5
Total available water capacity (cm, to 150 cm)	16.51	24
Total available water supply (cm, to 150 cm)	17.41	22
Depth to water table (cm)	17.21	23
Soil permeability rate (cm/hr)	19.86	13
Soil calcium carbonate (% by weight)	10.01	43
Soil cation-exchange capacity	20.69	9
Soil pH	12.2	38
Soil bulk density (g/cm3)	13.9	33
Organic matter content (% by weight)	20.15	12
Potential soil productivity	20.23	11
Soil erodibility factor, rock fragment free	20.54	10
Soil erosion by wind (tons/acre/year)	19.74	14
Percent soil passing sieve No. 10 (coarse)	22.05	4
Percent soil passing sieve No. 200 (fine)	21.52	6
Percent clay (< 0.002 mm size)	18.34	18
Percent sand (< 0.002 mm size)	22.36	3
Percent silt (< 0.002 mm size)	20.86	8
Percent of texture clayey	10.48	42
Percent of texture loamy	13.21	35
Percent of texture sandy	18.12	19
Percent of texture other	13.01	36
Alfisol (%)	18.56	17
Aridisol (%)	1.2	45
Entisol (%)	12.71	37
Histosol (%)	15.75	26
Inceptisol (%)	15.53	28
Mollisol (%)	11.9	39
Spodosol (%)	10.6	41
Ultisol (%)	11.44	40
Vertisol (%)	2.83	44