Studies on Transpiration Water Use of a Natural Quercus Liaotungensis Forest in the Semiarid Loess Plateau
|School||Graduate School,Chinese Academy of Sciences|
|Keywords||Loess Plateau Q. liaotungensis Sap flow Thermal diffusion probe Azimuth difference Radial difference Stand transpiration water consumption|
Liaodong oak, apricot, arborvitae, big fruit elm tree trunk Liaodong oak, semi-arid areas of the Loess Plateau of natural secondary forest, Granier heat diffusion probe for continuous monitoring of a growing season (April-October 2009) flow flux density and simultaneous monitoring of environmental factors (solar radiation, air temperature, air humidity, wind speed, etc.), the analysis of the response characteristics of the sap flow flux density of the main environmental factors, different orientation, different radial depth of the trunk The variation of the density of the liquid liquidity, estimated 2009 natural times of Liaodong oak forest growing season stand transpiration, aims to provide a theoretical basis for semi-arid areas of vegetation recovery and reconstruction. The main conclusions of the following aspects: (1) the Liaodong oak Flow overall diurnal variation on the solar radiation and air vapor pressure deficit showed the same trend, but the liquid flow peak appeared earlier, usually around 10:00 am. Phenological changes during the growing season, the flow flux density overall performance for the early (4-6 months) low, mid-and late (July-September), higher late (October), a rapidly declining trend. The index saturation curve to fit the function of the flow flux density and air vapor pressure deficit, to reflect the response characteristics of the flow flux density of each month on the air vapor pressure deficit. Curve characteristics for each month and the difference of the fitting parameters indicate that water consumption by transpiration process also by other factors such as soil moisture conditions. (2) flow flux density measured four orientations of the Liaodong oak east, west, south and north there are significant differences and significant correlation. The the Liaodong oak growing season (May-October) per plant transpiration water consumption and daily total solar radiation and daily average daytime air vapor pressure deficit index saturation curve fitting, fitting better. Two orientations and an orientation sap flow flux density measured whole plant transpiration water consumption and the estimated value of the four orientations difference of about 18% and 30%, respectively, between the different orientation of the liquid flow differences may be transpiration consumption water measurement important source of error. Liaodong oak (3) P. orientalis different radial depth of sap flow flux density between the existence of significant differences. The of Liaodong oak and oriental arborvitae sapwood radial liquid liquidity density variation is the trend cambium to heartwood maximum flow flux density decreases. Of oriental arborvitae 1-2 cm and 2-3 cm sap flow flux density change of 93% can be explained by flow flux density of 0-1 cm, has a significant linear relationship between the three; the Liaodong oak different radial The depth between sap flow flux density found no significant linear or curvilinear relationship. Liaotungensis, of oriental arborvitae 1-2 cm and 2-3 cm at maximum flow flux density, 0-1 cm at maximum flow flux density ratio different from individual to individual and render the differences. The relationship between sapwood area and DBH (4) the use of the the index saturation curve model fitting the Liaodong oak natural secondary forest tree species (Liaodong oak and wild apricot), combined with a single wooden stand investigation the DBH can calculate the corresponding trees sapwood area. Liaodong oak natural secondary forest species stands average the sapwood flow flux density has a significant seasonal dynamics characteristics. During the growing season the stand transpiration water consumption during the May-July. 2009 growing season not consider the radial and azimuth difference estimate stand transpiration total water consumption of 100.5 mm; average daily stand transpiration water consumption volume of 0.53 mm.