亚热带米槠次生林和杉木人工林林冠截留特征比较

通过对福建三明地区米槠次生林和杉木人工林林内穿透雨和树干茎流进行对比分析,研究2种林分类型对降雨再分配规律的影响及其关键影响因素。在研究区2种林分内分别选取了3个20m×20m标准样地,同时设置了穿透雨和树干茎流收集装置,每场降雨后测定相应的水量。结果表明:研究期内年降雨量为1 706.6mm,米槠次生林和杉木人工林林内穿透雨量没有显著差异,总穿透雨量分别为1 204.0mm和1 289.9mm,分别占年降雨的70.6%和75.6%;米槠次生林树干茎流量显著高于杉木人工林(p0.05),两者的树干茎流率分别为4.8%和2.7%;米槠次生林和杉木人工林的林冠截留率分别为24.7%和21.8%。林内穿透雨量与林冠郁闭度和叶面积指数呈负相关关系,说明林分郁闭度越高则穿透雨量越少。米槠次生林和杉木人工林林冠截留的差异主要受林冠开阔度和树皮结构的影响,因此树种差异显著改变了森林生态系统降水再分配模式。

Study on the Canopy Interception of Secondary Forest of Castanopsis carlesii and Chinese Fir Plantation in Subtropical China

This study was aimed to determine the effects of forest types on characteristic of rainfall partitioning and its key factors. The yield of throughfall, stemflow in two forest types (secondary forest of Castanopsis carlesii and Chinese fir plantation) were measured based on field survey in Sanming, Fujian. We selected 3 sample plots (20 m× 20 m) in each forest, and the yield of throughfall and stemflow was measured in the field after each rainfall. Our results indicated that the annual precipitation was 1 706.6 mm, and there was no significantly difference between the yield of throughfall in secondary forest (1 204.0 mm, 70.6% of gross precipitation) and Chinese fir plantation (1 289.9 mm, 75.6% of gross precipitation). The yield of stemflow in secondary forest (4.8% of gross precipitation) was significantly higher than that in Chinese fir plantation (2.7% of gross precipitation). The canopy interception rate was 24.7% and 21.8% of gross precipitation in secondary forest and Chinese fir plantation, respectively. In addition, the yield of throughfall was negative correlated to the canopy density and leaf area index (LAI), suggesting the forest with higher canopy density and LAI lead to low throughfall yield. These results indicated that the differential of rainfall partition in secondary forest and Chinese fir plantation were influenced by the different canopy openness and tree bark structure of the two forests, thus tree species could significant alter the patterns of rainfall partitioning.