Abstract: As an important ecological barrier and biodiversity hotspot in China, forest dynamics in the Qinling Mountains are of great significance to the regional ecological balance and biodiversity conservation. We established a 25 hm² forest dynamics plot in warm deciduous broad-leaved forest in Huangguan of the Qinling Mountains. Community surveys on woody plants with diameter at breast height (DBH)≥1 cm were conducted in 2019 and 2024. We analyzed tree species composition changes, fluctuations in community diversity indices, as well as dynamics of mortality and recruitment, aiming to reveal the structural characteristics and regeneration patterns of the community. The results showed that there was no species disappearance, and three species were added in 2024 compared to 2019. The trees exhibited an average annual mortality rate of 1.2% and a recruitment rate of 0.5%. The average diameter at breast height showed an increase of 8.6%. The top ten tree species in terms of importance value did not change, indicating dominant species were stable in the community. The Margalef index significantly increased, and the Shannon index showed a declining trend, reflecting an increase in species richness and the distribution of the individual number of tree species within the community tended to be uneven. Small-diameter individuals (1 cm≤DBH<5 cm) dominated in quantity compared with other diameter classes. Although individuals in this diameter class showed a high recruitment rate over the five-year period, the number of dead individuals accounted for 85.5% of the total mortality, leading to a decrease in the number of individuals in this diameter class. This result indicated that small-diameter individuals faced intense survival competition and environmental screening pressure during community regeneration, highlighting that the community was in a process of dynamic renewal and self-regulation.

Key words: forest dynamics plot, community regeneration, mortality rate, recruitment rate, diameter class