Stem taper functions for Betula platyphylla in the Daxing’an Mountains,northeast China  

作　　者：Muhammad Khurram Shahzad Amna Hussain Harold EBurkhart Fengri Li Lichun Jiang 

机构地区：[1]Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education,School of Forestry,Northeast Forestry University,Harbin 150040,People’s Republic of China [2]Department of Forest Resources and Environmental Conservation(MC 0324),Virginia Tech,310 West Campus Drive,Blacksburg,VA 24061,USA

出　　处：《Journal of Forestry Research》2021年第2期529-541,共13页林业研究（英文版）

基　　金：fi nancially supported by the National Natural Science Foundation of China(31570624);Applied Technology Research and Development Plan Project of Heilongjiang Province(GA19C006);Fundamental Research Funds for Central Universities(2572019CP15).

摘　　要：Accurate prediction of stem diameter is an important prerequisite of forest management.In this study,an appropriate stem taper function was developed for upper stem diameter estimation of white birch(Betula platyphylla Sukaczev)in ten sub-regions of the Daxing’an Mountains,northeast China.Three commonly used taper functions were assessed using a diameter and height dataset comprising 1344 trees.A first-order continuous-time error structure accounted for the inherent autocorrelation.The segmented model of Max and Burkhart(For Sci 22:283–289,1976.https://doi.org/10.1093/fores tscie nce/22.3.283)and the variable exponent taper function of Kozak(For Chron 80:507–515,2004.https://doi.org/10.5558/tfc80507-4)described the data accurately.Owing to its lower multicollinearity,the Max and Burkhart(1976)model is recommended for diameter estimation at specific heights along the stem for the ten sub-regions.After comparison,the Max and Burkhart(1976)model was refitted using nonlinear mixed-effects techniques.Mixed-effects models would be used only when additional upper stem diameter measurements are available for calibration.Differences in region-specific taper functions were indicated by the method of the non-linear extra sum of squares.Therefore,the particular taper function should be adjusted accordingly for each sub-region in the Daxing’an Mountains.

关 键 词：White birch Taper function MULTICOLLINEARITY AUTOCORRELATION Nonlinear regression 

分 类 号：S792.153[农业科学—林木遗传育种]