© 1987 Heron Publishing—Victoria, Canada
Evaluation of transpiration in a Douglas-fir stand by means of sap flow measurements
A. Granier
INRA, Centre de Recherches Forestières, Station de Sylviculture et de Production, Champenoux, B. P. 35, 54280 Seichamps, France / Received October 31, 1986
Summary
Transpiration of a Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand was evaluated by sap flow measurements during a 4-month period. Between-tree variation in sap flow
depended on crown class. On a sunny day, total transpiration was 1.6, 8.0 and 22.0 liters day–1 for suppressed, codominant and dominant trees, respectively. Transpiration estimated by sap flow fell below potential evapotranspiration
when available soil water decreased below 30% of its maximum value. Sap flow measurements gave transpiration values similar
to those obtained by the water balance method.
