Precipitation during the wettest quarter 0.014818 Nitrogen content of soil 1.07134 Precipitation during the hottest quarter 1.11778 Precipitation during the driest quarter 1.2345 Compound topographic index (relative wetness) 1.27849 Bulk density of soil 1.39526 Carbon content of soil 1.4283 Precipitation during the coldest quarter 1.57242 Ratio of precipitation to potential evapotranspiration 1.71836 Sum of monthly Tavg where Tavg >=5 deg C 1.75952 Solar interception 1.96584 Integer number of consecutive months where Tavg >= 5 deg C (Length of potential growing season) 2.81862 Temperature during the hottest quarter 2.82207 Elevation 2.87067 Temperature during the coldest quarter 2.99805 Available water holding capacity of soil 4.66171 Day/night diurnal temperature difference 5.32339