Succession-driven dynamics of ecosystem function and multifunctionality at regional scales: Evidence from subtropical secondary forests

In recent years, subtropical secondary forests have attracted considerable attention owing to their ecological and economic importance. However, identifying management strategies that facilitate positive succession and sustain ecosystem functioning remains a challenge. This study selected wood production (stand volume), carbon sequestration (carbon storage), and biodiversity as key indicators of forest ecosystem functions. Using forest inventory data from the National Forest Continuous Inventory (NFCI) of Jiangxi Province in 2006, 2011, and 2016, we investigated the ecosystem multifunctionality and interrelationships among these functions across different successional stages in a subtropical evergreen broadleaf forest, as well as their temporal dynamics. The results showed that wood production, carbon sequestration, and average multifunctionality increased with succession, while biodiversity remained consistent across stages. Synergistic relationships between wood production and carbon sequestration were sustained throughout all stages, and wood production and biodiversity maintained a neutral relationship. In contrast, the biodiversity–carbon sequestration relationship shifted in early- and mid-successional stages in 2011 and 2016, respectively, but remained stable and neutral in late-successional forests. As the multifunctionality threshold increased, mid-successional forests exhibited the fastest decline in function retention, followed by late-successional forests, while early-successional stages sustained multifunctionality longer. We conclude that enhancing multifunctionality in subtropical secondary forests requires not only promoting progressive succession but also implementing targeted management strategies—such as decelerating early- to mid-stage succession or accelerating mid- to late-stage progression—to fully realize their ecological potential.