滇中亚高山不同径级米槠树干液流昼夜特征及其影响因素  

Factors influencing and diurnal characteristics of stem sap flow of various diameter classes in Castanopsis carlesii in the central Yunnan alpine region,China

作　　者：丘雪明 王克勤[1] 和娴越 李珠宇 张广贺 赵洋毅[1] QIU Xueming;WANG Keqin;HE Xianyue;LI Zhuyu;ZHANG Guanghe;ZHAO Yangyi(College of Soil and Water Conservation,Southwest Forestry University,Kunming 650224,China)

机构地区：[1]西南林业大学水土保持学院,昆明650224

出　　处：《应用生态学报》2025年第1期21-30,共10页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(42067005);云南省农业联合专项面上项目(202101BD070001-075);云南省青年人才项目(YNWR-QNBJ-2019-215);云南省水土保持与荒漠化防治学一流学科开放课题(SBK20240045)资助。

摘　　要：以滇中亚高山磨盘山森林公园内天然常绿阔叶树种米槠为研究对象,采用TDP-30热扩散探测器和小型自动气象站对米槠树干液流及林地环境因子进行连续原位监测,研究米槠树干液流昼夜变化特征及其影响因素。结果表明:米槠大(35~45 cm)、中(25~35 cm)、小(15~25 cm)3个径级的树干液流速率日变化均呈明显的“昼高夜低”单峰曲线,且前半夜液流速率略高于后半夜。日尺度上液流速率变化均呈先上升后下降的趋势,整体变化幅度与径级大小呈正比,各径级液流速率大小依次为中径级>大径级>小径级。各径级整日液流量为19.21~72.27 mL·cm^(-2)·d^(-1),夜间液流量为0.97~6.04 mL·cm^(-2)·d^(-1),夜间液流对整日液流的贡献率为2.6%~21.5%,各径级夜间液流贡献率大小依次为小径级>中径级>大径级。米槠树干液流速率与太阳辐射、饱和水汽压亏缺、空气温度、相对湿度和风速显著相关,其中,昼间液流速率的主要影响因子是太阳辐射、饱和水汽压亏缺、空气温度、相对湿度和风速,夜间液流速率的主要影响因子是空气温度。在我国西南亚高山低温高湿生境下,米槠树干液流存在明显的昼夜变化规律,且昼间和夜间的树干液流影响因素存在明显差异;在估算米槠日总蒸腾耗水量时,不可忽视夜间液流的影响。We examined the diurnal variation characteristics of stem sap flow of Castanopsis carlesii,a natural ever⁃green broad⁃leaved tree species occurring in the Mopanshan Forest Park in central Yunnan.Environmental factors were recorded with a small automatic weather station.The results showed that the diurnal variation of the sap flow rate of trees from large(35-45 cm),medium(25-35 cm)and small(15-25 cm)diameter classes showed obvi⁃ous single⁃peak curves of‘day high and night low’.The sap flow rate in the first half of the night was slightly high⁃er than that in the second half.The change in sap flow rate on the daily scale showed a trend characterized by an initial increase followed by a decrease.The overall change range was proportional to the size of the diameter class.The sizes of sap flow rates across the diameter classes were in the order of middle diameter class>large diameter class>small diameter class.The daily sap flow rate across diameter classes ranged from 19.21 to 72.27 mL·cm^(-2)·d^(-1),while the nighttime sap flow rate ranged from 0.97 to 6.04 mL·cm^(-2)·d^(-1).The contribution rate of nighttime sap flow to the daily sap flow ranged between 2.6%and 21.5%.The contribution rate of nighttime sap flow in the diameter classes was in the order of small diameter class>middle diameter class>large diameter class.The sap flow rate in C.carlesii was significantly correlated with solar radiation,saturated water vapour pressure deficit,air temperature,relative humidity,and wind speed.The main factors influencing daytime sap flow rate were solar radi⁃ation,saturated water vapour pressure deficit,air temperature,relative humidity,and wind speed.The main factor influencing nighttime sap flow rate was air temperature.In the subalpine habitats of Southwest China characterized by low temperatures and high humidity,the sap flow of C.carlesii exhibited pronounced diurnal variation,with sig⁃nificant differences in the factors influencing sap flow between day and night.When estimating the total daily tr

关 键 词：亚高山森林 米槠 径级 昼夜树干液流 环境影响 

分 类 号：S792.17[农业科学—林木遗传育种]