Dynamics of a heat balance stem flow gauge during high flow.

(...) We evaluated the performance of several heat balance stem flow gauges during periods of high transpiration in sunflower (Helianthus annuus L.) with stems approximately 16 mm in diameter. Measurements in a controlled environment were used to compare gauge measurements to gravimetric estimates of transpiration. Gauges having heater widths of 10 mm severely overestimated flow as transpiration approached 200 g/h (…)