Diameter Class Structure and Spatial Distribution of Emmenopterys henryi in Zhejiang Jiulongshan National Nature Reserve

In July 2021, 35 permanent sample plots centered of one Emmenopterys henryi tree were established in natural distribution areas of E. henryi in Jiulongshan National Nature Reserve, Zhejiang province. Investigations were conducted on DBH, species of trees and shrubs with DBH of more than 2.5 cm and their distance to the center tree in the plots. The results showed that few small (DBH < 7.5 cm) and large trees (DBH > 37.5 cm) in the plots indicated difficult regeneration of the population. The number of conserved E. henryi trees decreased with the increase of diameter class,and the survival curve accorded with Deevey’s type II. The spatial distribution pattern of the E. henryi population changed from aggregation (within 4 m) to random (4-15 m) from the center. Most of the conspecific neighbors of the center E. henryi trees in the range of 3-15 m were from syngenetic groups. The spatial relation between the central E. henryi tree and associated trees changed from independent distribution (within 5.5 m) to mutual aggregated one (5.5-14 m). The aggregated trees around the central E. henryi tree were mainly small and medium. The central E. henryi tree and the super large associated trees distributed independently . In the range of 0-3 m, the DBH of associated trees was quite different from that of the centreal E. henryi trees. The results showed that the intraspecific competition of E. henryi in the Reserve was mainly from syngenetic trees. The surrounding of the mother E. henryi was favorite to the growth of heterospecific trees, while the growth of these heterogeneous small trees limit the regeneration of E. henryi.