哀牢山4类植物群落叶面积指数比较

Comparison of Leaf Area Index of Four Types of Plant Communities in Ailao Mountain

采用演替阶段的划分方法，把哀牢山人工灌木林、次生落叶阔叶林、次生常绿落叶阔叶混交林及原始常绿阔叶林4种群落划分为演替较早期、演替早期、演替中期和演替后期4个时期，利用植物冠层仪测定了4种群落的叶面积指数。结果表明：从演替较早期到晚期，物种多样性和树种密度逐渐增加，叶面积指数值也逐渐增大，演替较早期叶面积指数最小（2．27），演替晚期叶面积指数最大（5．60）。各个演替阶段的叶面积指数间差异极显著（P〈0．01），各演替阶段内测定的叶面积指数也有较大的标准差（0．35—0．73），说明各群落之间甚至同一种群落内，林冠结构都有较大差异。演替晚期乔木层叶面积指数最大，早期最小；演替中期灌木层叶面积指数最大，早期最小；4个阶段草本层叶面积指数差异不大。

Four types of plant communities at different successional stages, natural evergreen broad-leaved forest, secondary evergreen and deciduous broadleaved mixed forest, secondary deciduous broadleaved forest and artificial shrub forest, were selected to study the characters of leaf area index （LAI） by plant canopy analyzer in Ailao Mountain. Succession is classified as four stages： very early, early, intermediate, and late stages. Results show that the species diversity, density, and LAI increase gradually from the very early to the late successional stages. The lowest LAI value was 2.27 at the very early stage, and the highest LAI value was 5.60 at the late stage. LAI in different successional stages shows an extremely significant difference, and it also changes with large standard deviations （0.35 -0.73） at the same successional stage, which indicates a variety of canopy structure even at the same community. LAI of arbor layer is the highest at the late stage and the lowest at the early stage. LAI of shrub layer is the highest at the intermediate stage and the smallest at the early stage. The difference of LAI of herb layer is unobvious at different stages.