摘要
利用Granier树干液流测定系统,长期监测黄土高原半干旱区延安市南郊天然辽东栎林优势木的树干液流,并同步监测环境因子(空气温度、湿度、太阳辐射、土壤含水量)。分析3株优势木边材液流在生长季内各月份的日变化特征以及液流通量密度与环境因子的关系。结果显示:辽东栎液流日变化总体上与太阳辐射和空气水气压亏缺呈相同趋势,但液流峰值出现时间较早,通常为10:00左右。随着生长季内物候变化,液流通量密度总体表现为前期(4—6月)较低、中后期(7—9月)较高、末期(10月)迅速下降的变化趋势。采用指数饱和曲线函数对液流通量密度和空气水气压亏缺进行拟合,有效地反映了各月份液流通量密度对空气水气压亏缺的响应特征。各月份的曲线特征和拟合参数的差异表明,蒸腾耗水过程也受到土壤水分状况等其他因素的影响。
Granier-type thermal dissipation probes （TDP） were applied to measure tree sap flow dynamics in a naturally-regenerated Quercus liaotungensis forest in semiarid Loess Plateau region near Yan’an,Shaanxi Province.Air temperature,relative air humidity,solar radiation,and soil water content were monitored at the same time.In this paper,we measured diurnal courses of sap flow characteristics and analyzed relationships between sap flux density and environmental factors with three dominant trees during the growing season of 2009.The results showed that sap flux densities in Q.liaotungensis reached their daily peaks earlier than solar radiation and vapor pressure deficit,usually around 10：00 am,though the diurnal courses of sap flux density were generally similar to the changes of environmental factors.As the season and leaf phenology progressed,the overall performance of sap flux density was relatively low at early stage （April to June）,high in the mid and late stage （July to September）,and rapidly declining in the last stage （October）.Exponential saturation function was applied to fit the data sets of sap flux density and vapor pressure deficit,and the fitted curves effectively reflected the sap flow characteristics in different months.Differences in the fitted curves and parameters among months suggested that the transpiration process in these trees was also affected by soil moisture conditions or other environmental factors.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2011年第4期63-69,共7页
Scientia Silvae Sinicae
基金
中国科学院知识创新工程“百人计划”项目(kzcx2-yw-BR-02)
中国科学院知识创新工程“西部行动计划”项目(kzcx2-XB2-05)
中国科学院-日本学术振兴会据点大学群合作项目
关键词
黄土高原
辽东栎
边材液流
季节变化
热扩散探针
Loess Plateau
Quercus liaotungensis
sap flow
seasonal variation
thermal dissipation probe （TDP）
