尾叶桉地径与胸径、树高、材积相关性分析

【目的】建立尾叶桉地径与胸径、树高、材积的数学模型,为利用地径测算林木立木材积提供测算方法。【方法】实测148株尾叶桉立木的地径、胸径和树高,运用SPSS软件建立尾叶桉地径与胸径、树高、材积的回归模型,进行选优和适应性检验。【结果】研究区尾叶桉地径—胸径、地径—树高、地径—材积最优模型分别为D1.3=0.857D0-0.539、H=0.966D01.048、V=0.0000481D02.749,尾叶桉地径与胸径、树高、材积均显著相关。地径—胸径模型适应性检验的总相对误差为-1.14%、平均相对误差为1.29%,精度为98.46%;地径—树高模型适应性检验的总相对误差为13.07%、平均相对误差为-14.32%,精度为94.88%;地径—材积模型适应性检验的总相对误差、平均相对误差分别为-3.87%、1.69%,精度为94.70%。【结论】选出尾叶桉地径与胸径、树高、材积的3个最优回归模型,其中地径—树高模型总相对误差和平均相对误差过大,不提倡以尾叶桉地径直接估算树高;地径—胸径、地径—材积模型预测误差均在±5%以内,方程预测精度较高,可以用于估算立木材积。

Correlation analysis between ground diameter, DBH, height and volume of Eucalyptus

Objective The mathematical model about Eucalyptus ground diameter and DBH, tree height and volume was established for measuring growing stock. Method Relevant regression model was built for selection and adaptability test based on the measurements of ground diameter and DBH, tree height and volume of 148 strains. ResultEucalyptus optimal model of ground diameter, DBH, tree height and ground diameter-volume was D 1.3 =0.857D0-0.539,H=0.966D 0 1.048 , and V=0.0000481D 0 2.749 . Significant correlation existed in ground diameter and DBH, tree height and volume. Total relative error, average relative error and precision of ground diameter-DBH model was -1.14%, 1.29% and 98.46%, respectively. Total relative error, average relative error and precision of ground diameter-height model was 13.07%, -14.32% and 94.88%, respectively. Total relative error, average relative error and precision of ground diameter-volume model was -3.87%, 1.69% and 94.70%, respectively. Conclusion Among three optimal regression models, ground diameter-height model was not recommended for height estimation due to its big error, while the other two models with error within ±5% could be used for volume estimation.