闽北不同类型毛竹林冠层降水再分配特征

以中亚热带杉木纯林(Ⅰ)和常绿阔叶林(Ⅴ)为对照，对闽北地区竹杉混交林(Ⅱ)、毛竹纯林(Ⅲ)、竹阔混交林(Ⅳ)冠层降水再分配特征进行了研究。结果表明：各林分穿透雨率为462 %～862 %，平均穿透雨率排序由大到小为Ⅰ(770 %)、Ⅲ(750 %)、Ⅳ(737 %)、Ⅱ(703 %)、Ⅴ(677 %)；各林分树干茎流量排序由大到小为Ⅳ(692 mm)、Ⅲ(520 mm)、Ⅱ(373 mm)、Ⅴ(230 mm)、Ⅰ(176 mm)，树干茎流量随雨量增大而增大，不同类型毛竹林增加的比例大于杉木纯林和阔叶林；各林分产生树干茎流的最小响应雨量排序由小到大为Ⅱ(64 mm)、Ⅳ(69 mm)、Ⅲ(75 mm)、Ⅴ(89 mm)、Ⅰ(104 mm)；各林分林冠截留率为141 %～535 %，平均林冠截留率排序由大到小为Ⅴ(313 %)、Ⅱ(282 %)、Ⅳ(235 %)、Ⅲ(229 %)、Ⅰ(223 %)。5种林分穿透雨、树干茎流和林冠截留均与林外降雨量显著正相关（p＜001），其中穿透雨量和降雨量的关系用模型Y=a+bX拟合较好；林冠截留量和降雨量之间的关系用三次曲线（Y=β0+β1X+β2X2+β3X3）方程较拟合最好。综合分析表明，毛竹纯林对小到中雨的截留能力较好，竹杉、竹阔混交林对大到暴雨的截留能力较好。

Characteristics of rainfall redistribution under the canopy of different types Phyllostachys edulis forests in Northern Fujian province

The characteristics of rainfall redistribution under the canopy of three typical Phyllostachys edulis forests(Ph.edulis and Cunninghamia lanceolata mixed forest(Ⅱ),Ph.edulis pure forest(Ⅲ) and Ph.edulis and broad-leaved tree mixed stands(Ⅳ)) in the Northern of Fujian province were studied in comparison with C.lanceolata forest(Ⅰ) and evergreen broadleaved forest(Ⅴ).The results showed that: Throughfall rates ranged from 46.23 % to 86.22 %,the order of average throughfall rates was:Ⅰ(77.0 %)>Ⅲ(75.0 %)>Ⅳ(73.7 %)>Ⅱ(70.3 %)>Ⅴ(67.7 %).It was found that,as rainfall depth and intensity increased,the stemflow of three Ph edulis forests increased with a higher proportion than C.lanceolata forest and evergreen broadleaved forest.The order of stemflow rates was Ⅳ(69.2 mm)>Ⅲ(52.0 mm>Ⅱ(37.3 mm)>Ⅴ(23.0 mm)>Ⅰ(17.6 mm),and the order of least rainfall produced by stemflow in the five forest stands was:Ⅱ(6.4 mm)<Ⅳ(6.9 mm)<Ⅲ(7.5 mm)<Ⅴ(8.9 mm)<Ⅰ(10.4 mm).Throughfall,stemflow and canopy interception were linearly correlated to rainfall outside the stands at the extremely significant level(p<0.01),that the equation Y=a+bX could be used to show the relationship between the rainfall and througfall,and three curve equation(Y=β0+β1X+β2X2+β3X3) was applied to explain the relationship between rainfall and canopy interception.The canopy interception rates ranged form 14.1 % to 53.5 %,that the order was:Ⅴ(31.3 %)>Ⅱ(28.2 %)>Ⅳ(23.5 %)>Ⅲ(22.9 %)>Ⅰ(22.3 %).In summary,Ph.edulis and Cunninghamia lanceolata mixed forest had the highest interception capability among three different types Ph.edulis forest on heavy-hard rain condition while the pure Ph.edulis forest performed best with interception capability on light and moderate rain condition.