Sap flow characteristics of Liquidambar formosana Hance and its relationships with meteorological factors in Jiangxi degraded red soil region
Liquidambar formosana Hance is one of the excellent pioneer tree species, which has been widely used in the barren soils in subtropical area of China.L. formosana plantations have huge ecological benefits such as reduction of canopy leaching, remediation of heavy metals pollution and hydrological ef...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Zhejiang University Press
2013-09-01
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| Series: | 浙江大学学报. 农业与生命科学版 |
| Subjects: | |
| Online Access: | https://www.academax.com/doi/10.3785/j.issn.1008-9209.2013.02.061 |
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| Summary: | Liquidambar formosana Hance is one of the excellent pioneer tree species, which has been widely used in the barren soils in subtropical area of China.L. formosana plantations have huge ecological benefits such as reduction of canopy leaching, remediation of heavy metals pollution and hydrological effects, while at the same time they also consume large amount of water to maintain growth. Therefore, quantitative research on the water consumption characteristics by transpiration of the pioneer plantations has become a hotspot in the field of tree physiological ecology in recent years.In this study, sap flow velocity (v, cm/s) and meteorological factors were simultaneously observed using Granier's thermal dissipation probe and automatic weather station in a degraded red soil region in Jiangxi Province. Multivariate linear models were established to describe the relationships between sap flow velocity and relative meteorological factors. The models could not only reveal sap flow characteristics of L. formosana and its relationships with meteorological factors, but also estimate the whole tree transpiration according to meteorological data. The ultimate aim of this study was to provide theoretical basis for sustainable management strategies of L. formosana plantations and associated water resource.The results were as follows: 1) In sunny days, diurnal variations of sap flow displayed wide-peaked curves. Obvious seasonal dynamics was found mainly because of different time points in the time of starting, peak and the lasting time at the relatively high level of sap flow velocity. The starting time was earlier in June and July but latest in October. Sap flow velocity peaked earliest in July and kept sap flow rate of about 0.005 cm/s for up to 8 hours while peaked latest in October and kept sap flow rate of 0.002 cm/s for only 4 hours. The average monthly sap flow velocity followed the order of July (0.002 131) > June (0.001 937) > Aug. (0.001 932) > Sept. (0.001 861) > May (0.001 593) > Apr. (0.001 423) > Oct. (0.001 123).2) In rainy days, sap flow velocity was much lower than that in sunny days based on the same time point. The diurnal changes of sap flow exhibited remarkable differences due to the time and intensity of precipitation. In the rainfall condition, no obvious initiation except for small fluctuations of sap flow was observed due to high relative humidity and low solar radiation. Diurnal variations of sap flow would not be disturbed when precipitation happened before initiation or after termination of sap flow activity.3) About 1 hour time lag existed between sap flow and average net radiation (ANR) in clockwise direction and there were 1.5 hours time lag between sap flow and air temperature (Ta) as well as relative humidity (RH) in anti-clockwise direction. In the cases the time lag effect contained and not, the correlation strengths between sap flow velocity and meteorological factors were ANR (0.398) > RH (-0.258) >Ta (0.231), and ANR (0.595) > RH (-0.401) > Ta (0.028), respectively. Multivariate linear models indicated good fitting between sap flow velocity and meteorological factors, and the determination coefficients (R<sup>2</sup>) between three meteorological factors and sap flow velocity reached 0.85. The regression models and all parameters were significant at the level of P<0.01 in two cases. |
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| ISSN: | 1008-9209 2097-5155 |