Abstract: Ecological niche is a key indicator for the adaptive capacity of a species in the environment, offering insights into population status. Meanwhile, the spatial distribution of individuals provides crucial information for population dispersion characteristics and development trends. To clarify the regeneration dynamics of understory woody plant communities in a replanted broadleaved forest, we examined the woody species thriving beneath the replanted C. fissa forest, which was established 23 years ago after the clear-cutting of low-yield and low-efficiency Cunninghamia lanceolata plantation in Jianyang State-owned Forest Farm of Nanping City. Levins niche breadth and Pianka’s niche overlap were used to analyze the niche characteristics of species. Seven aggregation indices were employed to explore the spatial distribution pattern of dominant species with importance values greater than 1. The results showed that: (1) the seedlings of C. fissa were predominant in the understory community, with the largest importance value and niche breadth, which were 115.30% and 1.00 respectively. A substantial niche overlap was observed with other species, which maintained its dominant position with the upper canopy species. (2) There were no correlations between the importance values, niche breadths and niche overlaps. The niche overlap values among species pairs were distributed within the range of \[0, 1\], with most of the species pairs displaying significant overlap (0.5≤O_ik<1). (3) Most understory woody species were clustered in spatial distribution, and a few showed even distribution. The influence of different scales on the spatial distribution pattern of the populations within the small-scale range was mainly manifested in the change of clustering intensity. In general, the natural recovery of understory woody plants was at good condition, the interspecific relationship was stable, and the understory vegetation was in the stage of succession recovery.

Key words: clear-cutting regeneration, understory woody plant, Castanopsis fissa, niche, spatial distribution pattern