Tree water use, soil suctions and reference evapotranspiration in a semi-arid climate

This paper arises from a field study of blackbox trees (E. largiflorens) in a railway corridor in South-Eastern Australia. Sap flux gauges embedded in tree trunks were used to measure transpiration rates every 30 minutes and an on-site weather station recorded data for the determination of reference evapotranspiration every 15 minutes. Soil suction samples were taken to a depth of approximately four metres, on two occasions within the year of monitoring. Total suctions were measured and solute suctions were estimated from electrical conductivity testing. Trench excavations were made to record root extent of one tree specimen. The relationship between daily tree water use, reference evapotranspiration and soil moisture state are explored.