A Nonlinear-matrix Model for the Prediction of Mixed Uneven-aged Forests Growth with FORTRAN Program in Changbai Mountain, China

To compare the growth dynamic of the natural forest without any management practices with the forest under selection cutting regime in the Changbai Mountain, based on FORTRAN program we developed a simulator which inherently imbedded nonlinear growth model combined with matrix model. The nonlinear ingrowth and upgrowth models were established by the stepwise regression and mortality models were built for the small, medium and large diameter class by the empirical equation, all of which were combined with the matrix model to predict the growth dynamic of mixed uneven-aged forests. Chi-square test was used to test these models and no significant difference was observed between the actual and theoretical number of trees, which indicated the efficiency of the simulator developed. We applied the simulator and the result showed that basal area and volume of stands for the forest under selection cutting regime was significantly higher than the natural forest without any management practice (basal area: 35.6:18.4; volume 284.5:147.5). We concluded that the selection cutting could promote growth and yield of forest stands i.e. the forest could produce more volume if we conducted selection cutting than the forest with no management practice. The simulator developed in this study could be a useful tool for projection of current stand and therefore contribute to forest management planning.