Sap flow and water consumption of Populus×euramericana '74/76' saplings from cuttings planted on the North China Plain

Abstract

Simultaneous measurement with a heat balance and sap flow measuring system（Dynamax Inc.） to monitor the sap flow of Populus euramericana 74/76 and with an automatic weather recording system to record meteorological factors，such as the photosynthetically active radiation（PAR），air temperature，and relative humidity，was undertaken. According to weather records，the three most representative weather conditions （sunny，cloudy，and rainy days） were used to analyze the relationship of water use and meteorological factors. Results showed that PAR was always the dominant factor influencing sap flow，but sap flow diurnal variation and the main factors affecting it differed with weather conditions. Differences in sap flow density were the result of multi-meteorological factors，and the overall water use for saplings was in the order：sunny days ＞ cloudy days ＞ rainy days.［Ch，3 fig. 3 tab. 27 ref.］