Study On Water Consumption Of Three Commonly Used Garden Trees

Garden plants are an important part of landscape.They are in a extensive management level for a long time and consume a large amount of water resources every year,resulting in the waste of water resources.But garden plants can beautify the landscape to create a beautiful environment,but also has the ecological functions of absorbing pollution and dust,reducing bacteria and noise,conserving water sources,nutrient cycling,maintaining biodiversity,disaster prevention and mitigation,and so on.With the shortage of water resources,the water use of garden plants is the key problem of urban ecological construction.In this paper,TDP is used in this paper combination with the automatic meteorological observation system.The Euonymus bungeanus,Aesculus chinensis,Ginkgo biloba,was studied from the liquid flow,transpiration water consumption and its response to meteorological factors.The optimal model between the liquid flow rate and the main environmental factors was established,and the transpiration water consumption of trees was studied.The results show that:?1?Under typical weather conditions,the sap flow curves of E.bungeanus,A.chinensis and G.biloba show different characteristics.In sunny days,the start-up time of sap flow was the earliest,and the daily mean sap flow rate was the highest,followed by 0.00046 cm·s^-1,0.00111 cm·s^-1,0.00082 cm·s^-1.The daily mean liquid flow rate was the lowest,which was 0.00032 cm·s^-1,0.00092 cm·s^-1,0.00043 cm·s^-1,and was middle in cloudy days.The time to enter the trough is sunny and rainy at the latest.The day is earlier than the sunny day.The peak values were 12:30,13:00,17:00in clear days,12:30,11:30,12:10 in cloudy days and 15:40,15:40,15:30 in rainy days,with no obvious regularity.?2?The comparison of the liquid flow rates between the growing season and the end of the growing season of the E.bungeanus,A.chinensis,G.biloba showed that the sap flow rate at peak stage was 0.00022 cm·s^-1,0.00012 cm·s^-1,0.00028 cm·s^-1higher than that at the late stage.The start-up time of sap flow in the peak period was earlier than that in the end of the sap flow 2³ hours,and the time of entering the low valley was later than that in the end 1⁴ hour.?3?On the monthly scale,the water consumption of E.bungeanus,A.chinensis and G.biloba,showed an increasing trend from June to August,and that of E.bungeanus and G.biloba from August to October showed a downward trend.The water consumption of A.chinensis was slightly lower than in August,but more stable.Throughout the growing season,the water consumption of A.chinensis is the highest,is 1974.45 kg;the G.biloba is in the middle,is 1044.86 kg;and the E.bungeanus is the smallest,is 871.88 kg.?4?The study and analysis of sap flow rate and meteorological factors of three tree species showed that water vapor pressure deficit had the most direct effect on trunk sap flow rate,followed by temperature and light intensity.Due to the instability of wind speed in diurnal variation,the influence on trunk sap flow is less than that of other influencing factors.The transpiration water consumption of trees was positively correlated with light intensity,temperature,water vapor pressure deficit and wind speed.Generally speaking,the correlation coefficient between liquid flow rate and water vapor pressure deficit,temperature,light intensity and wind speed is large in sunny days,but small in rainy weather.Throughout the growing season.The best correlation between liquid flow rate and water vapor pressure deficit was August and September,and the weakest was October.The best correlation with temperature was August and the weakest was October.The best correlation with wind speed is September and the weakest is July.The correlation between light intensity and liquid flow rate was not significantly unified among the three trees in each month.?5?The optimization models between the sap flow rate of three kinds of trees and the main environmental factors were established and verified.Among the 42 stepwise regression models,16 models were introduced with three influencing factors:light intensity,temperature and water vapor pressure deficit.The average R² of sunny days is 0.833,the average R² of cloudy days is 0.802,and the average R² of rainy days is0.782.The errors of the verification results are within the range of statistically acceptable.