Objective Taking the Changbai Mountain spruce coniferous mixed forest as an example, this study compared the methods for dividing different stages of forest development and determined the most suitable method for dividing the development stages of Changbai Mountain spruce coniferous mixed forest, aiming to develop targeted forest management strategies for different stages of development and provide a methodological basis for the scientific division of natural forest development stages.

Method A total of 2 589 plot samples were divided by interspecies linkage-optimal segmentation method (A), forest facies characteristic discrimination method (B), TWINSPAN bidirectional indicator species analysis method (C), MRT multiple regression tree method (D), and TWINSPAN-based discriminant analysis method (E) of Jingouling Forest Farm of Wangqing Forestry Bureau of Jilin Province, northeastern China. Multiple comparisons were used to verify whether there were significant differences between different stages of stand development, and the anastomosis coefficient was used to compare the anastomosis between the classification results of different methods, and finally the classification results of five methods were compared from the aspects of tree species composition and stand characteristics.

Result The results of multiple comparisons showed that the nine numerical indicators used to describe the characteristics of forest stands in this paper basically had significant differences between different stages of stand development, indicating that the results were more reliable. Method D and E had the highest anastomosis coefficient, indicating that the division results were more consistent, while method B had a low agreement with other methods. From the perspective of development trend of the stand, the results of each method are roughly the same. As the forest gradually developed, the forest characteristic indicators increased, the diversity indicators decreased, and the tree species composition tended to be simpler. The differences were mainly reflected in the number of hectares and tree species composition indicators, and in the division results of different methods, the degree of difference between the indicators and the sample size of each stage were also different. From the specific analysis of various aspects, the division results of method E were more in line with the growth and development law of stands. In the first stage, a mixed spruce and fir coniferous forest was formed, and the forest grew rapidly. In the second stage, competition between trees intensified, and individual differentiation was significant. In the third stage, the forest was classified as a near natural forest, which was the target state of forest management.

Conclusion The discriminant analysis method based on TWINSPAN can better divide the developmental stage of forest stands, and divide the development process of Changbai Mountain spruce-fir-coniferous mixed forest into group establishment stage, competition stage and near-natural forest stage, which provides an important theoretical basis for forest scientific management.