GDD base 50 accumulated since April 1 = +3700 (+510 departure from normal) at Mountain Grove http://agebb.missouri.edu/weather/reports/gddTable.asp
March 2012 GDD base 50: 306+3700 = 4006
Phenology stages according to the Modified E-L system http://door.uwex.edu/files/2010/10/ModifiedEichhornLorennzsystem.pdf
