Sum of monthly Tavg where Tavg >=5 deg C 0.590031 Precipitation during the driest quarter 0.870349 Nitrogen content of soil 1.01955 Integer number of consecutive months where Tavg >= 5 deg C (Length of potential growing season) 1.04404 Precipitation during the wettest quarter 1.11744 Bulk density of soil 1.12649 Carbon content of soil 1.17988 Available water holding capacity of soil 1.31714 Solar interception 1.4016 Day/night diurnal temperature difference 1.40265 Temperature during the hottest quarter 2.06772 Compound topographic index (relative wetness) 2.60455 Ratio of precipitation to potential evapotranspiration 3.48266 Precipitation during the coldest quarter 3.97251 Temperature during the coldest quarter 4.53568 Precipitation during the hottest quarter 5.16621