Abstract:

The application of theoretical growth equations to the field of stand diameter structure has important significance in both theory and practice.In order to look for the inside and outside mechanism,and be elective and distinguished to use theoretical growth equations,this paper,in the view of stands and equations,studies and discusses this problems.The results showed:that there was not obvious influence of age,site index,density and thinning weight on modelling precision of six growth equations,such as Richards,Logistic and Korf so on,but there was a distinctly difference in modelling precision significant among equations.The inflection points of curve of stands cumulative diameter distribution mainly ranged,from 0.4 to 0.6. There was a close correlation between the value distribution of inflection points of growth equations and the modelling precision of equations,the wider the effective inflection point range of the best fit curve of equations was,or the higher the precision of inflection points was.The bigger the validity of inflection points was, then the modelling precision of equations would be higher.

Key words: Theoretical growth equations, Cunninghamia lanceolata plantation, Diameter structure, Stands factors, Inflection point