摘要
指出了削度方程不仅可用于推算单木及各材种的材积,更可用于林木生长过程的三维可视化重建,是林业生产实践中一种重要工具。以黑龙江省佳木斯市孟家岗林场60株红松人工林单木干形数据为例,以当前国内外林业中常用的简单削度方程、可变指数削度方程和分段削度方程为基础,采用SAS软件中的PROC NLIN模块对各模型参数进行求解,并采用确定系数(R2)、平均绝对误差(MAE)和均方根误差(RMSE)对各模型的拟合效果和预测能力进行了评价。结果表明:6种模型的整体拟合效果均相对较高,平均确定系数R2均在0.80以上;相同高度处的直径随着胸径的增加而呈增大趋势,但对树高的变化不够敏感;综合各项指标,该地区红松人工林的最优削度方程为可变指数削度模型(模型6),其模拟和预测R2均可达0.95以上,平均绝对误差均小于0.9cm,均方根误差也小于1.2cm。显然,筛选出的最优削度方程对精确红松人工林单木蓄积及指导合理造材具有重要作用。
Stem taper equation could be used not only the volume calculation of individual tree, but also the three--dimension reconstruction for the growth of individual trees. It has become the powerful tool in the practical industry. Stem taper of 60 trees for Korean pine plantation in Mengjiagang forest farm from Jiamusi of Heilongjiang province was used in the present study.The simple taper equation （equation 1-2）, variable exponential equation （equation 3- 5） and segmented taper equation （equation 6） commonly used in the literatures have been used in our study.PROC NLIN from SAS software was used to solve the parameters of the model.R^2 ,MAE and RMSE were used to validate the goodness-of-fit and validation results.The results show that the overall fitting effect of the six models is rela- tively high and the average coefficient of determination R^2 is above 0.80.The diameter at the same height increased with the increasing of diameter at the breast height, while it was not sensible to the change of tree height.Therefore, the variable taper equation （equation 6） performed best for the Korean pine plantation.The simulation and prediction of R^2 can reach more than 0.95 ,the average absolute error is less than 0.9cm,Root error is less than 1.2cm.As a result, the best taper equation is useful in volume calculation for Korean pine plantation.
作者
李元
Li Yuan(Liaoning Forestry Investigation and Planning Institute, Shenyang, Liaoning, 11012 2, China)
出处
《绿色科技》
2017年第17期87-91,共5页
Journal of Green Science and Technology
关键词
红松
削度方程
人工林
单木
干形
Korean pine
taper equation
plantation
individual
taper equation
