Precipitation during the hottest quarter 0.879835 Sum of monthly Tavg where Tavg >=5 deg C 0.92117 Nitrogen content of soil 1.18239 Precipitation during the coldest quarter 1.27398 Day/night diurnal temperature difference 1.29203 Bulk density of soil 1.33196 Precipitation during the driest quarter 1.35889 Carbon content of soil 1.40621 Precipitation during the wettest quarter 1.53756 Ratio of precipitation to potential evapotranspiration 1.59272 Integer number of consecutive months where Tavg >= 5 deg C (Length of potential growing season) 1.83205 Solar interception 1.86345 Compound topographic index (relative wetness) 1.93408 Available water holding capacity of soil 2.37563 Temperature during the hottest quarter 2.58844 Temperature during the coldest quarter 4.28872