1872:
Relationship of Transpiration, Reference Evapotranspiration and Tree Size During Six Years of Growth for Ilex x ‘Nellie R. Stevens'

Monday, July 27, 2009: 8:00 AM
Lewis/Clark (Millennium Hotel St. Louis)
Richard C. Beeson Jr. , Mid-Florida Research and Education Center, University of Florida, Apopka, FL
Actual evapotranspiration (ETA) of three Ilex x ‘Nellie R. Stevens’ trees  was determined continuously for six years using weighing lysimeters, as trees grew from rooted cuttings to 6 m in height.  Trees were grown in containers which are increased in diameter incrementally each year. Measured ETA was composed principally of transpiration because tops of the containers were covered to limit evaporation.  Trees size, consisting of projected canopy area, tree height, and trunk circumference at 15 and 30 cm above substrate level and just below the first major branch collar, were recorded every three weeks.  Reference evapotranspiration (ETo) was calculated daily using an on-site weather station.  Measured  values of trees size were used to normalize ETA.  Normalized ETA values were then modeled as a function of ETo.  Justification for the best model and its implications will be discussed.