Leaf Area Estimate of Erythroxylum simonis Plowman by Linear Dimensions

ABSTRACT This research aimed to determine an equation to estimate the leaf area of Erythroxylum simonis using the length and width of leaf blades. Two hundred leaf blades of this species were collected in Mata do Pau-Ferro, a State Park located in Areia, PB, Brazil. Regression analyses were used to determine the estimation equations. The linear, linear without intercept, quadratic, cubic, power and exponential statistical models were used. The criteria used for model selection were based on an examination of the coefficient of determination, the Akaike information criterion and standard error of the estimate. All the equations presented can be used to estimate the leaf area of E. simonis. From a practical point of view, the linear regression equation without intercept involving the product between length and width is recommended, using the equation Y=0.6426*LW, which corresponds to 64.26% of the product between length and width, with a coefficient of determination of 0.9936.

摘要：本研究旨在通过叶片的长度与宽度，建立西蒙氏古柯（Erythroxylum simonis）的叶面积估算方程。研究于巴西帕拉伊巴州阿雷亚市的Mata do Pau-Ferro州立公园采集了该物种的200片叶片。本研究采用回归分析方法构建叶面积估算方程，选用了线性模型、无截距线性模型、二次多项式模型、三次多项式模型、幂函数模型及指数函数模型共6类统计模型。模型筛选的评判依据为决定系数、赤池信息准则（Akaike Information Criterion, AIC）以及估计标准误。所有构建的估算方程均可用于西蒙氏古柯的叶面积估算。从实际应用角度出发，推荐采用以叶片长度与宽度的乘积为自变量的无截距线性回归方程，具体公式为Y=0.6426×LW，该式通过长度与宽度乘积的64.26%即可估算叶面积，其决定系数可达0.9936。