Nitrogen content of soil 0.73663 Sum of monthly Tavg where Tavg >=5 deg C 0.790889 Carbon content of soil 0.901905 Precipitation during the driest quarter 1.07995 Solar interception 1.12419 Precipitation during the hottest quarter 1.18258 Integer number of consecutive months where Tavg >= 5 deg C (Length of potential growing season) 1.18549 Precipitation during the coldest quarter 1.23764 Precipitation during the wettest quarter 1.25558 Bulk density of soil 1.27438 Day/night diurnal temperature difference 1.32161 Ratio of precipitation to potential evapotranspiration 1.52638 Compound topographic index (relative wetness) 1.83912 Available water holding capacity of soil 2.51116 Temperature during the hottest quarter 2.6755 Temperature during the coldest quarter 4.32638