Solar interception 0.09297 Precipitation during the wettest quarter 0.25859 Nitrogen content of soil 0.590572 Carbon content of soil 0.727757 Precipitation during the driest quarter 0.867693 Bulk density of soil 0.965556 Sum of monthly Tavg where Tavg >=5 deg C 0.9898 Day/night diurnal temperature difference 1.05665 Available water holding capacity of soil 1.92027 Temperature during the hottest quarter 1.95904 Integer number of consecutive months where Tavg >= 5 deg C (Length of potential growing season) 2.204 Compound topographic index (relative wetness) 2.88735 Temperature during the coldest quarter 3.23114 Precipitation during the coldest quarter 3.62607 Precipitation during the hottest quarter 3.76827 Ratio of precipitation to potential evapotranspiration 4.32458