Growth Models Of Natural Forests In Xiao Xing'an Mountains

Xiao Xing'an Mountain, as one of the most state-owned forest areas, plays an important and unique ecological part for adjusting Great Plains climate in the Northeast and North of China and stopping global warming. At the present, owing to the lack of Growth Models of Natural Forests, the system of forest inventory in the region of Xiao Xing'an Mountain cannot be scientifically predicted to the changes and dynamic of forestry resources, which seriously influences the framing of scientific and reasonable medium and long-term development plan about sustainable management and development of the forest in the region of Xiao Xing'an Mountain. Moreover, to accurately predict the dynamic of forestry resources, and realize the forest sustainable management, one of the best ways to study the regular growth and changes of main description factors of different forestry types in the region of Xiao Xing'an Mountain is to established pre-estimated growth and yield models. The data used to develop individual models for natural mixed forests are collected from survey permanent 457 sample plots in the area of Xiao Xing'an Mountain. Based on analyzing relationships between the stand description factors of individual trees such as height, diameter, age, volume of per hectare, basal area and number of trees per hectare using correlation analysis, this paper finds main competitive factors. In addition, investigation to obtain character of 350 sample trees has been made, by which mathematics model of ground diameter volume table of main tree species is deduced by regressing and imitating with seven of equations respectively, and compiled unitary and binary volume tables. The growth models for individual trees in the natural mixed forests, which have simple form, good predicting precision, and easy applicability, are developed by way of stepwise regression. At last stand growth and yield models are established through simultaneous equations with Forstat2.0 developed by Chinese Academy of Forestry Research to solve measurement error and parameter estimation question by estimating with two-step least-squares algorithm or three-step least-squares algorithm.The stand growth model developed in this paper can actually reflect the tree increment and be generally well suited for simulating tree and stand growth for natural mixed forests in the region of Xiao Xing'an Mountain. Furthermore, it will provide detail information of tree increment to intensive forest management and decision-making for natural mixed forest. Therefore, this research has the theoretic foundation and practical value.