Sum of monthly Tavg where Tavg >=5 deg C 0.963002 Carbon content of soil 1.18025 Nitrogen content of soil 1.27 Day/night diurnal temperature difference 1.30855 Precipitation during the driest quarter 1.31902 Precipitation during the wettest quarter 1.37626 Integer number of consecutive months where Tavg >= 5 deg C (Length of potential growing season) 1.65741 Bulk density of soil 2.06997 Available water holding capacity of soil 2.09553 Temperature during the hottest quarter 2.84272 Compound topographic index (relative wetness) 3.49793 Precipitation during the coldest quarter 3.98517 Ratio of precipitation to potential evapotranspiration 4.9537 Temperature during the coldest quarter 5.71416 Precipitation during the hottest quarter 6.61816 Solar interception 6.68727