摘要
【目的】通过建立含立地类型哑变量的湖南省金洞林场闽楠人工林单木树高曲线模型,为湖南省金洞林场闽楠人工林的目标树经营和生长预估提供理论依据。【方法】以湖南省金洞林场为研究区域,基于18块闽楠人工林固定样地2019年调查数据,选取了11个具有代表性的树高曲线模型对闽楠人工林树高-胸径关系进行了拟合,从中筛选出了拟合效果最好的模型作为构建哑变量模型的基础模型;通过对18块固定样地进行立地因子调查,采用数量化方法Ⅰ,以各林分的平均木优势高为因变量,立地因子为自变量,对立地因子进行评价,得到影响显著的立地因子,并通过划分等级和聚类分析来划分立地类型;将立地类型做为哑变量添加到基础模型参数及不同组合中,构建基于立地类型哑变量的金洞林场闽楠人工林单木树高曲线模型。【结果】在11个基础模型中,拟合的树高曲线最优基础模型为Weibull方程,其决定系数为0.7804最大,平均绝对误差(MAE)为1.7709,均方根误差(RMSE)为2.7013最小。以Weibull方程作为基础模型,在构建的含立地类型的哑变量模型中,将哑变量添加在参数c上效果最优,决定系数为0.8349,平均绝对误差(MAE)为1.5295,均方根误差(RMSE)为2.1316。对比于基础模型,决定系数提升了6.98%,平均绝对误差(MAE)降低了13.6%,均方根误差(RMSE)降低了26.7%。【结论】含立地类型哑变量的金洞林场闽楠人工林单木树高曲线模型拟合效果优于基础模型,并且具有更高的适用性,能反映不同立地类型下的树高、胸径生长差异,可以为湖南省金洞林场闽楠人工林的目标树经营和生长预估提供理论依据。
【Objective】Height-diameter model of individual-tree of Phoebe bournei plantation in Jindong forest farm based on dummy variable was established,which contains the dummy variable of site type.It provides the theoretical basis for the target tree management and growth prediction of Phoebe bournei plantation in Jindong forest farm of Hunan province.【Method】Taking Jindong forest farm as the research area,based on the survey data of 18 fixed sample plots of Phoebe bournei plantation in 2019,11 representative tree height DBH models were selected to fit the relationship between tree height and DBH of Phoebe bournei plantation in Jindong forest farm,Hunan province,from which the best model was selected as the basic model to build the dummy variable model The site factors were investigated by using the quantitative method i.the site factors were evaluated with the average dominant height of trees as the dependent variable and the site factors as the independent variable.The site factors with significant influence were obtained,and the site types were classified by classification and cluster analysis.The site types were added to the basic model parameters and different combinations as dummy variables to build the site-based model The single tree height curve model of Phoebe bournei plantation in Jindong forest farm with dummy variable.【Result】Among the 11 basic models,the optimal basic model of the fitted tree height curve is Weibull equation:its modeling accuracy(R2)is 0.7804 maximum,the mean absolute error(MAE)is 1.7709,and the root mean square error(RMSE)is 2.7013 minimum.Taking Weibull equation as the basic model,adding dummy variable to parameter C in the dummy variable model with site type has the best effect:modeling accuracy(R2)is 0.8349,mean absolute error(MAE)is 1.5295,root mean square error(RMSE)is 2.1316.Compared with the basic model,the coefficient(R2)is increased by 6.98%,the mean absolute error(MAE)is reduced by 13.6%,and the root mean square error(RMSE)is reduced by 26.7%.【Conclusion】The fit
作者
颜佳睿
李际平
曹小玉
唐涛
孙宇
王奕茹
YAN Jiarui;LI Jiping;CAO Xiaoyu;TANG Tao;SUN Yu;WANG Yiru(College of Forestry,Central South University of Forestry&Technology,Changsha 410004,Hunan,China)
出处
《中南林业科技大学学报》
CAS
CSCD
北大核心
2020年第11期47-54,共8页
Journal of Central South University of Forestry & Technology
基金
全国森林经营科技支撑科研专项(169201531-6)。
关键词
闽楠
人工林
树高曲线
立地类型
哑变量
Phoebe bournei
man-made forest
height-diameter model
site type
dummy variable
