几种常用的树木叶面积测量方法比较

Comparison of Leaf Area Measurement Method for Several Commonly Planted Tree Species

以随机采集的6种延安市区绿化植物（白蜡、刺槐、紫丁香、五角枫、银杏和月季）新鲜叶片为材料,分别用激光叶面积仪、AutoCAD和ENVI进行测量。通过统计比较发现,激光叶面积仪测量结果平均偏大,精度最低;AutoCAD与ENVI在测量结果上差异不显著,但在精度上Auto CAD高于ENVI。AutoCAD测量叶片面积的平均耗时为139.6 s,是ENVI方法的3～4倍。通过AutoCAD测量方法测定以上6种树木叶片的长度、宽度和叶面积,并拟合出6种树木的叶面积线性方程,相关系数与决定系数均达到极显著水平。经过验证,这6个叶面积线性方程均是可靠的,可以用于延安市这6种植物叶片面积的测量和叶面积衍生指标的估算。

Fresh leaves of six species of greening plants （ Fraxinus chinensis Roxb. , Robinia Pseudoacacia L. , Sy- rinbga oblata Lindh , Acer pictum subsp, mono （Maxim） Ohashi. , Ginkgo biloba Linn. And Rosa chinensis Jacq. ） in Yan＇an City were randomly collected as experimental material, and their leaf area were measured with laser leaf area meter, AutoCAD and ENVI respectively. The statistics comparison suggested that the measurement of laser leaf-area meter came to higher results than AutoCAD and ENVI did, and its accuracy was lowest. AutoCAD and ENVI were not significantly different in the measurement results, but the AutoCAD is higher than ENVI in accuracy. The average e- lapsed time measuring leaf area through Auto CAD was 139.6 s, 3-4 fold of ENV1 measurement. In this paper, the leaf from 6 species of trees were measured for length, width and leaf area by using AutoCAD, and the linear equations of their leaf area were obtained through fitting while correlation coefficient and determination coefficient were extremely significant. Verified results showed that the linear equation ware all reliable and therefore could be used for measuring the area of leaves from the 6 species and estimating the leaf area derived index in Yan＇an city.