摘要
本文对南方红壤区常见林地类型-杜仲人工林的穿透雨、树干流和林冠截留的水文过程进行了监测,并在对其影响因素进行分析的基础上,探讨了林下降雨的空间分布规律。结果表明:杜仲林对降雨的再分配受到降雨特征影响,穿透雨、树干流和林冠截留量与降雨量呈显著的正相关(P<0.05),随着雨量或雨强的增加,穿透雨率升高,截留率降低,并且两者在高的雨量和雨强下逐渐趋于恒定。在测定期间,杜仲林穿透雨率为72.7±7.8%,树干流率为7.7±1.8%,截留率为19.6±9.9%。杜仲林下穿透雨存在明显的空间异质性,随着与树主干距离的增加,穿透雨率逐渐提高,靠近树干的林冠内部穿透雨率显著低于林冠边缘,而且随着降雨量的增加,穿透雨的空间变化减少,异质性降低。每mm降雨的单株树干流(cm3/mm)与胸径、冠层厚度和树高均呈显著的正相关性(P<0.05),但是与冠幅和枝下高的相关性不显著(P>0.05)。对于林内雨的组成,树干流与穿透雨的比率随着雨量或雨强的增加而呈减小趋势,但树干流对降雨具有明显的汇集作用,随着降雨量的增加,对降雨的汇集效果先提高后降低。林冠截留在减少林内雨量的同时,也显著地改变了林下降雨的空间分配,使林内局部(如树干流周围)水分输入反而高于林外。
Hydrological process of canopy is an important consideration from forest ecological and hydrological points of view, which affects the total depth and spatial distribution of water input, lags the onset time of sub-canopy rainfall and influences the soil and water conservation in forest ecosystems. As a tree species commonly used for reforestation in southern China, Eucommia ulmoides serves an important example of water resource management and sustainability of long-term productivity. Therefore, the partitioning of gross rainfall into throughfall, stemflow and interception in the E. ulmoides forest was studied from July 2004 to September 2005 at the Ecological Benefit Monitoring Station of the Yangtze River Protection Forest in Cili County, Hunan Province （29°30＇N, 110°10＇E）, which were aggregated to assess the law of canopy hydrology. Results showed that rainfall redistribution of canopy in the E. ulmoides forest was closely related to precipitation characteristics. Throughfall, interception and sternflow of E. ulmoides positively correlated with rainfall depth （P 〈 0.05）. As rainfall depth and intensity increased, throughfall percentage of gross rainfall increased, but interception percentage of gross rainfall decreased. And throughfall and interception percentages of gross rainfall stabilized at larger rainfall depths. Over the whole measurement period, throughfall, sternflow and interception percentages of gross rainfall were 72.7 ± 7.8 %, 7.7 ± 1.8 % and 19.6 ± 9.9 %, respectively. Throughfall below the canopy had clearly spatial heterogeneity and throughfall percentage of gross rainfall at positions closest to the trees was lower than those under the peripheral part. With increasing the distances between sampling site and stem, throughfall percentage of gross rainfall gradually increased. Moreover, the spatial variation in throughfall （i. e., CV of throughfall percentage of gross rainfall） decreased with increasing rainfall depth. Stemflow volume per mm of rainfall per stem （cm^3·m
出处
《资源科学》
CSSCI
CSCD
北大核心
2007年第2期52-59,共8页
Resources Science
基金
国家自然科学基金委创新群体项目(编号:40321101)
国家自然科学基金资助项目(编号:30230090)
关键词
杜仲林
降雨再分配
穿透雨
树干流
水文效应
Eucommia ulmoides
Rainfall redistribution
Canopy interception
Sternflow
Forest hydrology
