两种测定天然次生林叶面积指数方法的比较

The Comparison of Two Methods of Measuring Leaf Area Index of Natural Secondary Forest

采用叶面积指数直接测定方法（称重法）与间接测定方法（冠层分析仪测定法），对帽儿山天然次生林区叶面积指数进行测定，运用相关性分析和对比分析对测定结果进行研究。研究结果表明，直接测定法结果为实测叶面积指数，间接测定方法结果小于前者，精度比前者低25％-40％，但两组结果相关关系显著，间接测定值能较好地反映林木的叶面积指数大小变化。天然次生林中林层结构对冠层分析仪测定有很大的影响，是造成两种方法差异的主要原因。

The direct measurement method namely weighing method and indirect measurement method namely canopy analyzer measurement method to determine leaf area index were used to measure leaf area index of natural secondary forest of Mao＇ershan Mountains. The correlation analysis and the comparative analysis were used to study the determination results. The research results showed that the values of direct measurement were actual measured leaf area index and the values of in direct measurement were less than those of the actual measured with the precision lacking approximate 25% - 40%. The two results related significantly and the values of direct measurement can better reflect the changes of leaf area index of trees. Canopy structure in natural secondary forest had great effects on canopy analyzer, which was the main reason causing the difference of the two methods above.