The Study On The Individual Tree Growth Models Of Regional Compatibility For Main Tree Species In Heilongjiang Province

The data used to develop individual growth model were collected from remeasured permanent sample plots of two year 1995 and 2000 in HLJ province, northeast China. The correlation of diameter increment of individual trees and tree size, competitive status, site condition were analysed. Distance-independent Individual-tree Growth Models have been developed using stepwise regression method, and the area compatible growth models of all tree species have been developed with a dummy variable method.The research results showed that the main variable which influence on the increment at breast height of individual trees was tree size and then competition indexes. SCI and ELV of the site condition were slightly related with diameter increment. The natural logarithm of DBH (lnD) was included in individual growth models for all tree species except Pinus densiflora. The diameter increment was directly proportional to tree diameter for each species. For the competitive indexes in the growth models mean of the relative G and the ratio of diameter of subject tree with maximum diameter(DDM) were related to the breast height section area increment. As DDM increased, the diameter increment was decreased except poplar and pinus sylvestris plantation.The site conditions, such as aspect was performance less important in increment predictions and was seldom introduced in the final models. the growth models of all tree species were established by a dummy variable method, could effectively solve the problem of area compatible, and was superior to the growth models established by all Application of the whole area of data. Using independent data set, validation measures were evaluated for predicting models of diameter increment developed in this study. The result indicated that the estimated precision values of models were all greater than 90%. so the models would been widely applied in actual production.The individual tree growth model developed in this study can actually reflect the tree increment of all species and be generally suited for simulating tree and stand growth in the Forest Bureau of HLJ province. and it will provide detail information of tree increment to intensive the forest management and decision-making. Furthermore, the dummy variable growth models could effectively solve the area compatible problem.