云南省德宏州西南桦人工林立地指数表编制

Establishment of the Site Index Table for Betula alnoides Plantations in Dehong Prefecture,Yunnan Province

【目的】以云南省德宏州5县(市)西南桦人工林为研究对象,编制该州西南桦人工林立地指数表。【方法】共设置65块样地进行生长调查,每个样地选取1株平均优势木进行树干解析,获得1009对树高—林龄数据;应用3倍标准差法剔除异常数据,选取Korf、Richards和Weibull等8个常用方程拟合1000对优势树高—林龄数据,通过决定系数(R^(2))、绝对残差(AMR)、均方根误差(RMSE)和相对残差(RAR)等统计指标筛选导向曲线;应用标准差调整法编制立地指数表,并对其进行卡方检验、预报精度检验和落点检验。【结果】经模型拟合筛选出R^(2)最大以及AMR、RMSE和RAR最小的Richards方程作为导向曲线,方程表达式为H=39.453[1-exp(-0.067t)]1.018;以基准林龄为15年,指数级距为2 m,划分8个立地指数级,据此编制立地指数表;经卡方检验、预报精度检验和落点检验证明所编表合格。【结论】本研究所编制立地指数表可用于评价云南省德宏州及类似地区西南桦人工林的立地质量,从而提升该区域西南桦人工林的科学经营管理水平。

[Purpose]To establish the site index table of Betula alnoides plantations in Dehong Prefecture,Yunnan Province based on the object from five counties or cities.[Method]A total of 65 plots were set up for growth investigation.One dominant tree was selected from each plot for stem analysis and 1009 pairs of tree height-tree age data were obtained.The method of three-time standard deviation was used to eliminate the abnormal data,then eight common equations such as Korf,Richards and Weibull were selected to fit the 1000 pairs of dominant height-tree age data,and the guide curves were selected by comparing the model statistics indexes including the determination coefficient(R^(2)),absolute residual error(AMR),root mean square error(RMSE)and relative absolute residual(RAR).The standard deviation adjustment method was used to compile the site index table,and the Chi-square test,prediction accuracy test and landing point test were further conducted for the table.[Result]The Richards equation with the largest R^(2),the smallest AMR,RMSE and RAR was selected as the guide curve,and the equation expression was H=39.453[1-exp(-0.067t)]1.018.Reference tree age was determined as 15 years,eight site index classes were divided by taking two meters as the index interval,and the site index table was established.Through Chi-square test,prediction accuracy test and drop point test,it was proved that the site index table was qualified.[Conclusion]The site index table developed in the present study can be used to evaluate the site quality of B.alnoides plantations in Dehong Prefecture and similar areas,and to improve plantation management of the species.