Population structure and dynamic characteristics of Cercidiphyllum japonicum in Houhe National Nature Reserve, Hubei Province

Cercidiphyllum japonicum is a tertiary relict species that was once widespread across the Northern Hemisphere but is now a rare and endangered plant in China, valued for its ornamental, medicinal, and scientific importance. Understanding the structure and dynamics of its wild populations is essential for forecasting their future and informing conservation strategies. This study, conducted in the Houhe National Nature Reserve, Hubei Province, analyzed a population of 62 individuals across 23 sampling plots. Based on detailed field measurements of diameter at breast height (DBH), a static life table was compiled and population dynamics were projected using age class dynamics indices and time series analysis. Results showed the population inhabits sandy, organic-rich, weakly acidic yellow-brown soils. The age structure approximated an irregular, spindle-shaped pyramid, characterized by a complete absence of germinated seedlings and a reliance on sprouting for regeneration. The population dynamic indices (Vpi > V′pi > 0) indicated a marginally growing but stable population that is highly sensitive to environmental and anthropogenic disturbances. The survival curve conformed to the Deevey-III type, indicating high mortality in early life stages. Time-series forecasting suggested that the current abundance of middle-aged individuals could maintain the population in the short term. We conclude that recruitment failure, intense environmental filtering, and historical logging are the primary drivers of its endangered status. Conservation efforts must therefore prioritize artificial regeneration to supplement seedlings, active management of existing sprouts, and the establishment of a long-term monitoring program for this vulnerable population.