Abstract:

Aims: Studying the dynamic changes of temperate coniferous forests is crucial for understanding their formation and maintenance. This study aimed to investigate the dynamic changes of a temperate natural coniferous forest, providing a scientific basis for developing forest conservation and restoration strategies. 

Methods: We selected a 6 ha temperate natural coniferous forest dynamics plot in the West Tianshan National Nature Reserve, Xinjiang, as the research site. We conducted thorough surveys of woody plants with a diameter at breast height (DBH) ≥ 1 cm in 2008, 2014, 2019, and 2024, respectively. We analyzed and compared the changes in community composition, structure, and dynamics over these years. 

Results: (1) Over the 16-year period, the abundance of woody plant individuals in the plot decreased. Specifically, the total number of Picea schrenkiana individuals declined from 1,310 to 1,122, a reduction of 13.09%, with the most significant decrease occurring between 2014 and 2019. (2) Across the three time intervals, the mortality rates of woody plants were 0.06%, 2.88%, and 1.99%, respectively, showing an initial increase followed by a decrease. The recruitment rates were 0.60%, 0.60%, and 0.10%, respectively, remaining stable initially before a sharp decline. The turnover rates were 0.62%, 3.39%, and 2.08%, respectively, remaining stable initially, then sharply increasing, and finally decreasing. The loss and growth of aboveground biomass in the community were highest during the 2014–2019 period, while the net change in aboveground biomass was greatest during the 2008–2014 period. (3) The recruitment rate, mortality rate, and turnover rate of the community were all positively correlated with species richness. Soil available nitrogen content had a significant negative effect on the net change in aboveground biomass, whileas soil pH had a significant positive effect. 

Conclusion: This study demonstrates that the Tianshan Picea schrenkiana community in the western Tianshan Mountains of Xinjiang is undergoing significant structural and functional changes and is at risk of decline due to high mortality and low recruitment rates. This research provides an important scientific basis for the ecological restoration and biodiversity conservation strategies of Tianshan Picea schrenkiana forests.

Key words: temperate coniferous forests, Picea schrenkiana, community structure, mortality rate, recruitment rate