Solar interception 0.463164 Sum of monthly Tavg where Tavg >=5 deg C 0.527863 Nitrogen content of soil 0.755541 Ratio of precipitation to potential evapotranspiration 0.767669 Carbon content of soil 0.785996 Integer number of consecutive months where Tavg >= 5 deg C (Length of potential growing season) 0.929581 Precipitation during the driest quarter 1.00368 Day/night diurnal temperature difference 1.08763 Precipitation during the coldest quarter 1.18915 Compound topographic index (relative wetness) 1.24616 Precipitation during the wettest quarter 1.25524 Bulk density of soil 1.26623 Precipitation during the hottest quarter 1.53069 Available water holding capacity of soil 2.04862 Temperature during the hottest quarter 2.18839 Temperature during the coldest quarter 4.20576