Studies On Structure And Dynamics Characteristics Of Quercus Variabilis Population

Quercus variabilis is widely distributed in 22 provinces of China. It is a major tree species of the forestation in the forest regions to south of north China. It is also a constructive species in deciduous broad-leaved forests of China.This paper is a research on Quercus variabilis community in Xiashu forest farm of Jiangsu province, which locates in the north-subtropical zones. It is a report about studies on structure and dynamics characteristics of Quercus variabilis population from the view of Dendroecology. This study integrates with the investigation of forest community and radial growth models of Quercus variabilis based on the Software of EXCEL, SPSS and MATLAB. The results show that:By the application of step-wised regression method, the models display that the diameter sizes(r2 ,r,lnr) of woods are the comprehensive manifestation values of their influencing factors. With the introduction of the diameter of woods, the growth fitting of different woods can be modified individually by the models and the models are improved significantly. The innovative content and primary fruit in the study are the radial growth models and the technique established by the combination of tree-ring analysis, autoregression and step-wised regression method. Furthermore, the models can be applicable extensively. The series models are obtained from the sample data of analyzing 16 tree-ring woods of the predictive group which is about as long as 50 years. And the models are tested by the sample data of 6 ones of checking group. It tests the standard deviation and residual error of prediction group and checking group. The prediction precisions are all approximately 96%. By analysis of the living stands growth for Quercus variabilis individuals, the fast-growing period of the population is from 5 years to 35 years. The basal-area growing will be steady when Quercus variabilis population is 160 years old, and it will be stable when 200 years.The study of Quercus variabilis population structure using age estimation models illustrates that the size class and age structure are incomplete in investigation areas. It's revealed that the reserve of seedlings and saplings is deficient, and the mature individuals of Quercus variabilis show a normal distribution. The saplings are the bottle neck species of population natural regeneration. The main limiting factors for Quercus variabilis seedlings'germinating and saplings'growing are the light deficiency and low disturbance in stands.