Abstract: This research aims to explore the response relationship of trunk sap flow to environmental factors such as air temperature, relative humidity and wind speed, analyze the characteristics of sap flow under the erosion of stem borers, and make preliminary explorations for the application of sap flow research in pests and diseases. The self-developed heat pulse velocity （HPV） sap flow meter was used to measure the daily sap flow in the trunk of the street tree Sapindus mukorossi, Michelia chapensis, and Ginkgo biloba, and the environmental factors such as temperature, humidity and wind speed are simultaneously measured by the ecological environment parameter data acquisition instrument. The healthy wood sap flow of each tree species was significantly correlated with factors such as temperature, humidity, and saturated vapor pressure deficit （VPD） （P<0.05）, while the change of the damaged wood sap flow was weakly affected by environmental factors, and the peak sap flow is lower than healthy wood. The consistency index D between the affected and healthy trees were 0.897, 0.913, and 0.937, respectively. RMSE were 8.561, 4.617, 2.594, and MAE were 5.527, 3.153, 1.663. The HPV method can effectively measure the dynamic changes of tree sap flow. The daily pattern of stem sap flow of the wood damaged tree changed significantly, and the degree of the response to environmental factors such as temperature, humidity, and VPD was weakened.

Key words: HP, sap flow, wood borers, stem segment test, environmental factors