ObjectiveFocus on the natural secondary forest in Maoershan Mountain of northeastern China, this paper tries to find out the optimal tree species composition of different forest types at varied succession stages by comprehensive evaluation of stand characteristics, so as to provide a theoretical basis for the construction of a reasonable forest management model in this region.

MethodBased on the datasets of 53 permanent sample plots in Maoershan Mountain in 2004 and 2016, a total of 12 indicators, namely uniform angle, neighborhood comparison, mingling degree, diameter distribution, stand density, stand volume growth, volume, mean height, natural regeneration density, stand potential density, Simpson diversity index and Pielou evenness index, which reflected three aspects of the forest characteristics (i.e., stand structure characteristics, stand vigor and tree species diversity), were selected to study the influence of different ratios of hard and soft wood in 3 different mixed forest types on forest structure, using the method of linear-weight comprehensive evaluation, based on effects of entropy-AHP method. One forest type was soft broadleaved mixed forest (the proportion of hard broadleaved trees in the stand was 0%, 10%, 20% and 30%), another was soft-hard broadleaved mixed forest (the proportion of hard broadleaved trees in the stand was 40%, 50% and 60%), and the last one was hard broadleaved mixed forest (the proportion of hard broadleaved trees in the stand was 70% and 80%).

ResultAmong the 3 forest types, the overall mingling degree of mixed forest was relatively high (0.62−0.69), while the horizontal distribution pattern (0.53−0.56), size differentiation degree of forest trees (0.47−0.51), diameter distribution (q value: 1.09−1.19) and natural regeneration number (368−571 plant/ha) of stand were relatively poor. Stand volume growth showed a maximum weight (0.191) and neighborhood comparison showed a minimum weight (0.021). The proportion of hard broadleaved trees with the highest comprehensive evaluation value in the 3 forest types was 20%, 60% and 80%, respectively.

ConclusionThe optimal tree species composition for the natural secondary forest in Maoershan Mountain differed significantly among different forest types. The optimal proportion of hard broadleaved trees for the 3 forest types (soft broadleaved mixed forest, soft-hard broadleaved mixed forest and hard broadleaved mixed forest) was 20%, 60% and 80%, respectively. The conclusion of this study can provide reference for the adjustment of tree species composition of broadleaved secondary forest in this region.