Abstract: The natural regeneration of Pinus henryi plantations in Bashan Forest Farm and the influencing factors were analyzed, to provide a theoretical basis for promoting natural regeneration through management practices. Based on survey data, the quality of natural regeneration seedlings at different height levels (<30 cm, 30 cm ≤ H < 50 cm, ≥50 cm) was assessed using the adjusted Class I seedling density, and a comprehensive evaluation system was developed to explore influencing factors of natural regeneration. The results showed that the sum of the importance values of dominant regeneration species exceeded 60% in all plots, with Prunus dielsiana dominating most of them. Obvious differences in seedling quality were observed across various plots based on adjusted I-level density. Regeneration density, seedling height, and the proportion of large seedlings had a significant impact on regeneration success. The highest comprehensive evaluation coefficients were observed in plots 3 and 2, while the lowest were in plots 5 and 6. Correlation analysis indicated that the regeneration index was positively correlated with diameter at breast height (DBH) and tree height, and negatively correlated with stand density. Stepwise regression analysis further indicated that DBH and stand openness facilitated natural regeneration, while high stand density suppressed it. Natural regeneration of pioneer broadleaf species such as Prunus dielsiana contributed to the diversity and stability of the Pinus henryi-broadleaf mixed forest. The comprehensive index evaluation proved applicable to assessing natural regeneration success. DBH, stand density, and openness index were identified as the dominant factors affecting natural regeneration. Appropriate regulation of stand structure could effectively enhance the natural regeneration of P. henryi plantations.

Key words: Pinus henryi plantation, natural regeneration, stand structure, influencing factors