江西省大岗山主要森林类型降雨再分配特征

以江西大岗山地区杉木林、常绿阔叶林和毛竹林为研究对象,分析其对降水再分配过程的影响.结果表明: 2012年4-6月,研究区降水量为531.6 mm,以小到中雨为主,单次最大降雨量为61.7 mm.研究期间,毛竹林总穿透雨量最大,常绿阔叶林最小.降水量相同条件下,毛竹林与杉木林的穿透雨量相差不大;降水量较大且相同时,常绿阔叶林的穿透雨量明显小于另外两种林型;穿透雨在林内有明显的空间变异性.杉木林、常绿阔叶林和毛竹林的树干径流率分别为1.4%、8.9%和8.8%.杉木林树干径流与另外两种林型差异极显著(P<0.01).3种林型树干径流量均与前期降水条件有关,毛竹林相关程度最小,杉木林最大.3种林型林冠截留量大小依次为杉木林(30.5%)>阔叶林(25.5%)>毛竹林(19.2%).在该地区常见降雨条件下(小雨),杉木林截留率明显高于另外两种林型.

Rainfall redistribution traits of three main forest types in Dagangshan Mountains of Jiangxi Province,China.

The redistribution processes of rainfall due to the canopy were studied on three typical forest types (Chinese fir forest, evergreen broad leaved forest and Phyllostachys pubescens forest) in Dagangshan Mountains of Jiangxi Province. The results showed that from April to June, 2012, the total precipitation was 531.6 mm, with the maximum single rainfall of 61.7 mm. The rainfall in this area was mainly light and moderate. During the research period, the total throughfall of P. pubescens forest was the greatest, and that of evergreen broad leaved forest was the smallest. The throughfall of P. pubescens and Chinese fir forest were almost equal at the same rainfall intensity. However, the throughfall of evergreen broad leaved forest was smaller than those of the other two types of forest at the same high rainfall intensity. Throughfall presented a distinct spatial variability within each forest. Stemflow of Chinese fir forest, evergreen broad leaved forest and P. pubescens forest were 1.4%, 8.9% and 8.8%, respectively. There were significant differences (P<0.01) in stemflow between the Chinese fir forest and the other two types of forests. In addition, the moisture degree of forests before a rain event greatly influenced the quantity of the stemflow. The effect was strongest in the Chinese fir plantation and weakest in the P. pubescens forest. The proportion of interception to rainfall was in a descending order of 30.5%, 25.5% and 19.2% for the Chinese fir forest, the evergreen broad-leaved forest and the P. pubescens forest, respectively. The Chinese fir forest had the obviously greater interception rate than the other two types of forests under usual rainfall in the study area.