TITLE:
Water Use of Juvenile Live Oak (Quercus virginiana) Trees over Five Years in a Humid Climate
AUTHORS:
Richard C. Beeson, Hang Thi Thu Duong, Roger Kjelgren
KEYWORDS:
Quercus virginiana, Irrigation Scheduling, Irrigation Modelling, Container Production, Landscape Irrigation
JOURNAL NAME:
Open Journal of Forestry,
Vol.8 No.1,
November
24,
2017
ABSTRACT: To meet minimum spring flows, water management
districts in Florida sought to make both agriculture and urban landscapes water
efficient, which includes tree farms. Quercus
virginiana, commonly known as live oak trees, is endemic to Central Florida and among the most
popular landscape trees for their gracefulness and spreading shade. To provide
a basis for irrigation allocations both during production and in landscapes,
daily actual evapotranspiration (ETA) in liters for three live oak
trees was measured with weighing lysimeters over five years, beginning with
seedlings and continuing until trees averaged 7.2 meters in height. Empirical
models were derived to calculate ETA based on crown horizontal projected area (PCA) or trunk
caliper (TCSA), adjusted daily by changes in evapotranspiration (ETO).
Average ETA to produce these live oaks was 62,218 L cumulative over
5.5 years. Effectively transpiring leaf, tree water use volume divided by ETO,
was closely related to PCA over five years with the slope of this relationship
being equivalent to a Plant Factor of 0.93. The product of ETO and
this Plant Factor can be used to estimate depth of live oak water demand in
urban landscapes. Also, this Plant Factor can estimate water demand volume in
nurseries and landscapes when combined with PCA, and similarly the slopes for
TCSA can be used to estimate ETA water volume from measured trunk
diameter.