Natural population structure and spatial distribution pattern of rare and endangered species Dacrydium pectinatum

In order to study the survival status and distribution pattern of Lu Junsong (Dacrydium pectinatum) population, the natural populations of Lu Junsong in three different distribution areas of BWL, DLS, and JFL were investigated, and the species diversity and dominant species composition and age class of the natural community were analyzed The spatial heterogeneity of the three aspects of structure and distribution pattern shows that: (1) The species richness and diversity index of the tree layer of the three natural communities of Pinus elliottii are high, and the basic performance is BWL>JFL>DLS, and it is much higher than Temperate and subtropical forest communities in mid-to-high latitudes; the communities are mostly small-density populations, with few tree species occupying an absolute dominant position, which conforms to the general rule of tropical mountain rain forest species composition. (2) There are differences in age class structure, BWL and JFL populations There is a trend of decline. The common feature is that the number of young trees is small, and the proportion of adult and old trees is relatively high; the number of young trees in the DLS population has the highest proportion of all individuals and belongs to the growing population. (3) The overall distribution of BWL and DLS populations is clustered. From juvenile to old age, the distribution changes from agglomeration to a uniform distribution. The JFL population as a whole and at different development stages are uniformly distributed; the aggregation intensity is DLS>BWL>JFL, young trees>adult trees>old trees. Lu Junsong is a tropical mountain rain forest. The key species and constructive species are of great significance to the study of the origin and flora characteristics of the tropical rain forest in Hainan. Aiming at its survival status, artificial auxiliary measures such as opening of forest gaps and reasonable thinning can be used for protection and Update and rejuvenate.