Objective  The formation mechanism and diffusion pattern of the spatial distribution of Cratoxylum cochinchinense were studied to promote the protection and management of the natural forest and landscape construction and application in Pearl River Delta areas with poor ecological environment.

Method  We used quadrat survey method and selected C. cochinchinense stands distributed in three different areas (Chashan area and Baiyun mountain in Guangzhou, and Shihua mountain in Taishan). The maps of population spatial distribution and diffusion dynamics were drawn using digital processing with ArcGIS platform. These maps were used for analyzing seed dispersal mode and dispersal dynamics. The function model of diffusion rate (y)-DBH (x) of the C. cochinchinense population was established for predicting population diffusion rate.

Result  The C. cochinchinense trees always aggregated at the local downwind and showed a distribution trend in sampled areas. The growth in projection area of canopy always increased first and then decreased, and the functions of diffusion rate-DBH were univariate quadratic equations in different sampled areas. The growth of canopy of single C. cochinchinense tree first increased and then decreased, and the function model of diffusion rate(y₀)-DBH(x₀) for single C. cochinchinense tree was: y₀=−0.013 5x₀²+0.310 6x₀+0.111 3 (R²=0.999, P=0.000).

Conclusion  1) C. cochinchinense population spread by wind. 2) The diffusion rate of canopy first increased and then decreased. The growth of canopy area increased to the peak when the diffusion rate reached the maximum, and the growth of canopy area was 0 when the diffusion rate was 0. At this time, diffusion of the population was limited. 3) Under artificial management, the diffusion rate of canopy reached the maximum of 1.90 m²/cm when tree DBH was 11.5 cm and the population belonged to the 6th diameter class. At this time thinning should be appropriately done to ensure the maximum benefits. The population diffusion was limited when tree DBH was 23.4 cm and the population belonged to the 12th diameter class. At this time thinning must be done to promote the growth and update of population.