影响丝栗栲树干液流速度的环境因子分析

Analysis of environment factors of stem sap velocities of Castanopsis fargesi

利用热技术对江西大岗山国家级生态站区常绿阔叶林优势树种之一的丝栗栲树干液流进行了研究,并用梯度自动气象站对气象和土壤等环境因子开展了同步监测。结果表明:丝栗栲树干液流速度表现为双峰曲线;影响丝栗栲树干液流的主要环境因子为风速、10cm土壤温度、20m大气温度、20m空气相对湿度和100cm土壤水势;其次是太阳辐射强度、光合有效辐射和饱和水汽压。即土壤温度和大气温度是影响树干液流速度的主导因子。

The stem sap method is the main method to determine tree transpiration internationally, but the sap flow of tree species in evergreen broad-leaved forest has not been studied yet. Especially it is not clear in the relation between velocities of stem sap flow and environmental factors. Therefore, we employ sap flow sensor to monitor sap flow of Castanopsis fargesi in evergreen broad-leaved forest of Dagangshan Mountain. Meanwhile, an Automatic Weather Station was applied to measure meteorological parameters and soil factors. The results showed that the stern sap flow behaved as double peaks curve. Among 28 environmental factors, wind velocity, soil temperature at 10cm underground, air temperature at 20m above ground, relative humidity at 20m above ground and soil water potential are the major factors affecting sap flow rate. The next factors are solar radiation intensity, Photosynthetic Active Radiation （PAR） and saturation vapor pressure. Above all, the dominant factors were soil temperature and air temperature. The conclusion has momentous significance to accurately evaluate the effect of forest in water circle of subtropical zone.