Dynamic Changes of Stand Structure of Natural Soft Broad Leaved Secondary Forest in Maoershan

Taking natural soft broad leaved secondary forest in Maoershan as the object, we analyzed the data of 4 periods within 13 years and explored the dynamic change law of forest structure in Maoershan, which provides a theoretical basis for the scientific management of natural secondary forest. The results show that the diameter distributions from 2007 to 2020 are all approximate to the inverse J-shape, where the R² of Weibull model varied between 0.889 and 0.917; the R² of the logistic distribution model from 2007 to 2020 ranged from 0.982 to 0.989; The diameter classes of the stands are even distribution, and the compositions of tree species are complex. In the non-spatial structure index, except for the increases of the stand density(24.18–26.54), the diversities of tree species(0.809–0.755), the stabilities of the stand(0.96–1.12) and the number and densities of trees are all decreased; The spatial structures did not change significantly during the 13 years. The horizontal distribution pattern (0.525–0.518) of the stand showed an aggregated distribution, the forest competition was in the middle (0.504–0.499), the overall mixing degree of the stand was moderate(0.615–0.640), the vertical complexity of the stand decreased (0.542–0.526), and the spatial comprehensive index of the stand changed stably. To sum up, the forest structures of Maoershan natural soft broad leaved secondary forest remain relatively stable and presents a positive succession trend. In the future, stand thinning should be done properly to expand growth space and improve habitat conditions. Precious tree species such as Pinus koraiensis should be properly replanted to increase economic value and improve stand pattern.