应用TDP技术研究油松树干液流流速

应用TDP(ThermalDissipationProbe)技术对油松树干液流及其影响因素进行了初步研究,经过野外近1a的实地定位观测,研究结果显示该研究区油松在研究年份中除4、6、7、8月份外,土壤含水量低于10%,土壤水势小于-15MPa.油松树干液流速率与土壤容积含水量和土壤水势呈明显线性相关关系.油松在全生长期受水分胁迫影响.油松树干液流速率在7、8月份明显受气象因素影响,在5、6月份则主要受土壤水分影响,在9、10月份不同时间段分别以土壤水分或气象因素为主要影响因素.在7、8月份油松树干液流速率与太阳总辐射、大气水势、空气相对湿度、绝对温度呈明显的线性相关关系.从油松树干液流速率及影响因素的变化可以看出,油松在该研究区大部分时间受到干旱胁迫的影响,通过抚育间伐降低密度,割灌、除草降低其他植物的耗水竞争,均可能是有利于油松良好生长的营林措施.

Research on the rate of stem sap flow in Pinus tabulaeformis by using TDP method

The stem sap flow velocity of Pinus tabulaeformis is studied by using the Thermal Dissipation Probe(TDP). After one year of in situ study, the results show that: Except April,June, July and August, the soil moisture is lower than 10% and the soil water potential is lower than-1 5 MPa in the whole research period. There exists a multi linearship between the stem sap flow velocity and the soil moisture, soil water potential. %Pinus tabulaeformis% has been facing draught stress in the whole research period. In July and August the sap velocity of %Pinus tabulaeformis% is mainly influenced by weather conditions, and the soil moisture is not the major factor. In May and June the soil moisture is the limiting factor of sap velocity of %Pinus tabulaeformis%. In September and October soil moisture or weather conditions mainly influences the sap velocity. There exists a multi linear relationship between the stem sap flow velocity and the total solar energy, the relative humidity, the air water potential, the absolute temperature in July and August. The authors conclude that %Pinus tabulaeformis% is facing water stress in most growing period. The authors suggest that thinning, bushing and weeding should be good tending methods to be used to minimize the competence of other plants for water.