【摘要】 利用热扩散式探针法对庐山自然保护区内不同胸径大小的日本柳杉在2016年7月树干液流情况进行连续监测,并同期监测样地区域的气象因子(降雨、气温、湿度、太阳辐射等),揭示不同胸径日本柳杉的液流变化规律和蒸腾耗水特征以及对主要气象因子改变的响应情况。结果表明:液流呈现明显昼夜变化规律,其日变化呈多峰曲线型,平均每日峰的次数晴天约3.5次,雾天3次;在典型晴天,液流每日平均起始时间为6:45,总持续时间15 h,首次峰值出现时间约为11:45,峰值总持续时间4.25 h,雾天,液流每日平均起始时间为7:30,总持续时间11.5 h,首次峰值出现时间约为10:45,峰值总持续时间4.5 h,且液流峰值出现时间、下降时间、结束时间、最大峰值出现时间雾天均要早于晴天;不同胸径树干液流的日变化规律有差异,总体来看,随着树干胸径的增加,液流日波动次数增加,各样树的液流首次到达峰值和峰值结束的时间分布不同,液流最大峰值随着胸径的增加而增大;晴天液流日均值与胸径的大小存在良好线性正相关关系,而雾天的线性相关拟合一般,太阳辐射和大气水汽压亏缺(VPD)是树干液流的主要影响因素,树干液流对太阳辐射和VPD均以幂函数形式呈正相关关系,液流变化对于太阳辐射变化存在45～135 min的时滞效应,但是其峰值持续时间比太阳辐射峰值持续时间少1 h;在典型晴天,胸径越大树木日总蒸腾量越大,蒸腾量与胸径以幂函数的形式呈现正相关关系,在雾天,蒸腾量与胸径之间的正相关性不如晴天。更多还原

【Abstract】 The thermal dissipation probe was used to continuously monitor the sap flow of Cryptomeria japonica in different DBH in the Lushan Nature Reserve in July 2016, and monitored the meteorological factors(rainfall, temperature, humidity, solar radiation, etc.) in the meantime.The sap flow change rules and transpiring water consumption characteristics of Cryptomeria japonica with different DBH and its response to the changes of main meteorological factors were revealed. The results show that the flow pattern shows obvious diurnal variation,and the diurnal variation of the flow is multi-peak curve, the average number in sunny peaks is about 3.5 times,the foggy day is 3 times. In the typical sunny day, the average daily start time was at 6:45, the total duration was15 h, the first peak appeared at about 11:45, the peak duration was 4.25 h. In foggy day, the average daily start time of the sap flow was at 7:30, duration was 11.5 h, the time of the first peak appear was about 10:45, the peak duration was 4.5 h, and the peak time of the sap flow, the falling time, the finish time and the highest peak time were longer than sunny days. The diurnal variation of the sap flow in the DBH was different. On the whole,with the increase of the DBH, the number of times of sap flow fluctuation was increased, the first peak and end time of sap flow in different trees are different, the highest peak of the sap flow increased with the increase of the DBH. In sunny day, the mean of the sap flow and the DBH had a good linear positive correlation, while in foggy day, the linear correlation fit not so good. Solar radiation and VPD are the main meteorological factors of the sap flow, there was a positive correlation between the sap flow and the solar radiation and the VPD in the form of a power function. The flow variation had a delay effect of 45-135 min to the solar radiation, but the sap flow peak duration was less than solar radiation peak about 1 h. In the typical sunny day, the larger the DBH was, the greater the transpiration was, and the transpiration had a positive correlation with the DBH in the form of a power function. In the foggy days, the positive correlation between transpiration and DBH was not as good as sunny day.更多还原