Evaluation of the sap flow using heat pulse method to determine transpiration of the Populus euphratica canopy

摘要

The sap flow of the sampled Populus euphratica stems at different radial depths and directions had been studied in Ejina Oasis,in the lower reaches of the Heihe River.Based on sap flow measurements,the transpiration of the entire canopy was calculated.Results showed a linear correlation between the sap flow and the sapwood area of the P.euphratica.Through the analysis of the diameter at breast height in the sample plot,it was found that the distribution of the diameters and the corresponding sapwood area was exponentially correlated,with the coefficient of correlation being 0.976,7.The calculated transpiration of the Populus euphratica canopy was 214.9 mm based on the specific conductivity method.