Abstract:

A Granier TDP method was applied to continuously monitor sap flow of Schima superba which is native tree species in South China and data of the changes of environmental factors was synchronously collected to explore dynamic characteristic of trunk sap flux density at different temporal scales and its relation with different dominance and environment factors. The results showed that the daily pattern of sap flux density of dominant, middle and depressed woods exhibited a singlepeak curve. The maximum sap flux density of middle wood was slightly higher than that of dominant wood, but the depressed wood was far below those of middle and dominant. Photosynthetically active radiation (PAR) was major factor influencing trunk sap flux density of dominant and middle woods, while air temperature (TA) influenced mainly the depressed wood under the drought stress. Soil moisture (SM) did not apparently influence instantaneous sap flux density, but daily accumulated amount of flux in dominant woods.

Key words: trunk sap flux density, Schima superba, dominance