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FOREST RESOURCES WANAGEMENT ›› 2021›› Issue (1): 156-163.doi: 10.13466/j.cnki.lyzygl.2021.01.020

• Technical Application • Previous Articles     Next Articles

Construction of Difference Site Index Model for Larix Principis-rupprechtii Plantation

WANG Zhibo1(), JI Meng1(), LI Yongle2, LI Yinxiang1, MA Shiming3, ZHANG Haidong1   

  1. 1. Inner Mongolia Academy of Forestry Science,Hohhot,Inner Mongolia 010010
    2. Sumu Mountain forest farm of Xinghe County,Xinghe,Inner Mongolia 013650
    3. Forestry Science Research Institute of Ulanqab,Jining,Inner Mongolia 012000
  • Received:2020-11-05 Revised:2020-12-09 Online:2021-02-28 Published:2021-03-30
  • Contact: JI Meng E-mail:wang_zb123@163.com;jimeng04@tom.com

Abstract:

In the paper,the Larix principis-rupprechtii plantation in Sumu Mountain forest farm of Yin Mountain was taken as the research object.Based on the data of 43 analytic trees,the difference site index models were constructed based on Richards equation.The results showed that the difference model fitting results were significantly better than the basic model,with R2 above 0.96,RMSE between 0.86 and 0.96,and MAE below 0.42.The model derived by ADA method,the fitting result with b or c as free parameter is better than that with a as free parameter.In the model derived by GADA method,it is more reasonable to assume a linear relationship between the free a parameter and the variable X0.Through such methods as statistical analysis,residual analysis and site index curve cluster comparison,by applying GADA method,the difference model derived by free parameters $a=e^{X_{0}}$,$c=c_{1}+c_{2} X_{0}$ is the best model,which meets the requirements of biology and statistics.Higher site index has the greater extreme value of tree height and annual growth of dominant trees,and the earlier the curve reaches the inflection point.The results can provide basis for the scientific evaluation of site quality of Larix principis-rupprechtii plantation.

Key words: site index model, Richards equation, algebraic difference approach, generalized algebraic difference approach, Larix principis-rupprechtii plantation

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