Scientific Research and Essays

  • Abbreviation: Sci. Res. Essays
  • Language: English
  • ISSN: 1992-2248
  • DOI: 10.5897/SRE
  • Start Year: 2006
  • Published Articles: 2764

Full Length Research Paper

Polymorphic dominant height and site index models for Chinese fir (Cunninghamia lanceolata) plantations in Southern China

  Ai-Guo Duan, Jian-Guo Zhang*, Shu-Zhen Tong and Cai-Yun He
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Forest Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, PR China.
Email: [email protected]

  •  Accepted: 10 May 2013
  •  Published: 30 June 2013




Difference methods based on six growth equations namely: Richards, Weibull, Korf, Logistic, Schumacher and Sloboda were adopted to build polymorphic dominant height and site index equations for Chinese fir plantations in Southern China. Data from stem analysis of 157 trees were used for the model construction. The performance of 15 equations including 10 kinds of difference equations was compared under different conditions. Effects on modeling precision caused by the variation of fitting data sets, site index, stands age and free parameter were analyzed and discussed. The results show that the attributes of inflection points of the biological growth equations had very important effects on their precision, while modeling dominant height. Difference equations had a better modeling precision for regional data sets than the prototypes of equations. The polymorphic dominant height equations, such as the two-parameter polymorphic form of Korf, Richards and Weibull and the three-parameter polymorphic form of Sloboda, showed higher precision. The two-parameter polymorphic form of Korf equation was selected to build a polymorphic site index equation for Chinese fir plantations.


Key words: Chinese fir plantations, difference equation, dominant height, polymorphic site index equations, precision.