喀纳斯自然保护区2树种树干液流变化特征及其与气象因子的关系

采用热扩散式探针法 (TDP) 对西伯利亚落叶松、疣枝桦的阳生面和阴生面树干液流进行测定，结合自动气象站同步监测光合有效辐射 (PAR)、空气温度 (T)、空气湿度 (RH)、饱和水汽压、风速等气象因子，分析气象因子与2树种树干液流的相关关系。结果表明：西伯利亚落叶松和疣枝桦阳生面、阴生面树干液流日变化均呈明显的 “昼高夜低” 的典型单峰曲线型变化，且阳生面高于阴生面，树干液流变化幅度西伯利亚落叶松大于疣枝桦。在生长季节，西伯利亚落叶松阳生面、阴生面树干液流月平均值均呈递减趋势，其液流平均最大值出现在6月，平均最小值出现在9月。疣枝桦阳生面树干液流月平均值呈先增后减的趋势，最大值出现在8月，最小值出现在6月；阴生面树干液流呈递增趋势，最大值出现在9月，最小值出现在6月。相关分析表明，气象因子与2树种树干液流相关性大小依次为：气温 > 光合有效辐射 > 空气相对湿度 > 风速 > 水汽压，气温和光有效辐射是影响液流速率的主要因子。

Characteristic of Stem Sap Flow of Two Tree Species and Analysis with Meteorological Factors in Kanas National Nature Reserve

Stem sap flow velocities of Larix sibirica and Betula pendula were measured by using thermal dissipation probe method on sunny side and shade side.At the same time, the correlation between meteorological factors and the stem sap flow of two tree species was analyzed according to the related environmental factors that include photosynthetically active radiation (PAR), air temperature (T), ralative air humidity (RH), saturation vapour pressure and wind velocity were recorded continuously by using automatic weather station. The results were as follows: the diurnal variation of stem sap flow on Larix sibirica and Betula pendula displayed a typical single peaked curve in the sunny side and the shade side, the sunny side was higher than that of the shade side. The variation range of Larix sibirica was higher than Betula pendula. During the growing season, the monthly average of stem sap flow for Larix sibirica showed decrease tendency with its maximum appearing in June and minimum in September. The monthly average of stem sap flow for Betula pendula on the sunny side was firstly increased and then decreased, with its maximum appearing in August and minimum in June. The monthly average of stem sap flow for Betula pendula on the shade side showed increase tendency, with its maximum appearing in September and minimum in June. Correlation coefficients declined following the order of air temperature, PAR, RH, wind velocity and saturation vapour pressure. That is, sap flow of the two species were mainly affected by air temperature and photosynthetically active radiation.