| 摘要: |
| 我们用Schnute模型模拟了单木胸径生长过程,并与其它7个常用的生长模型进行了对比分析。研究结果表明,Schnute模型实际上是含有2个可变参数的差分生长模型,可由4参数的Chapman-Richards模型导出。在模型应用中,可用2个不同年龄时期的胸径观测值估计Schnute模型中2个可变参数,并使拟合的曲线通过这两个观测值,因而能够大幅提高模型预测精度。当Schnute模型作为普通回归模型使用时,其拟合效果与预测效果与其它模型相比并无明显优势。研究所用数据为火炬松人工林16年逐年观测数据,并用SAS (V8)进行模型拟合与验证。 |
| 关键词: 胸径,Schnute模型,代数差分模型, SAS |
| DOI： |
| 投稿时间：2018-02-22修订日期：2018-05-02 |
| 基金项目: |
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| Using Algebraic Difference Model with Two Variable Parameters to Simulate the Growth of Diameter at Breast Height |
| Tian Yumei,Tang Xiaoyan,Fang Kunsheng |
| (Yushu Forest Bureau, Jilin Province;Guizhou University of Finance and Economics;Guangzhou Tianquan Information Science and Technology Co., Ltd.) |
| Abstract: |
| We used the Schnute model to simulate the growth of diameter at breast height (DBH) for single tree, and compared it with other seven commonly used growth models. The research results showed that Schnute model was virtually an algebraic difference growth model with two variable parameters,derived from a four-parameter Chapman-Richards model. When simulating the growth of DBHs, two previous DBH observations could be used to estimate the two variable parameters, and the estimated curve would fit between the two DBH observations, thus remarkably increase the accuracy of prediction. When the Schnute model was used as an ordinary regression model, however, it only slightly outperformed other models with respect to model fitting and prediction. Annual DBH observations spanning sixteen years of Loblolly pine were used for model fitting and validation with SAS (V8). |
| Key words: diameter at breast height, Schnute model, algebraic difference model, SAS |
