Hainan Province, a tropical island region in China, boasts a rich diversity of natural resources, including a substantial population of venerable trees (VTs). VTs, or venerable trees, represent an important ecological and cultural resource. However, accelerated urbanization and increased human activities pose significant threats to their survival. This study investigates the status of VTs in Hainan Province, analyzing key characteristics such as age, height, diameter at breast height (DBH), and crown width. We evaluated 373 species and 18,459 VTs, examining the natural and anthropogenic factors that drive their distribution. Results indicate a rich and diverse species composition, with a pyramidal age structure, where VT numbers decline with increasing age, suggesting a sufficient reserve of younger VTs. Spatial distribution patterns reveal a clustering of VTs, with higher densities in northern Hainan and reduced presence in coastal and seaward urban areas compared to inland regions. The optimal model identified habitat heterogeneity and environmental energy as the primary drivers of VT species diversity, with MAPR (maximum minus minimum precipitation) emerging as the strongest predictor of species richness. The best combination model showed a greater independent effect on VT species diversity patterns than the other models, which had lower values. Based on these findings, we propose protective measures to address the current threats and preservation challenges facing Hainan’s ancient trees.

The island ecosystem, due to its inherent fragility, is highly susceptible to both natural disturbances and human activity, resulting in fragmented habitats for island plant populations. This study investigates the population structure and dynamics of Heliotropium arboreum in such fragmented environments, aiming to understand its survival and adaptability. We selected six H. arboreum populations across different habitats, analyzing their diameter class structures, static life tables, and survival curves through a field survey using sample line investigations. Structural and dynamic characteristics of each population were examined, and future trends predicted using time series analysis. Results indicated that the second, third, and fourth age classes comprised the majority, representing 63%-86% of individuals, suggesting a growing population with an irregular pyramid-like structure. However, some age classes show decline, with weak growth rates, high sensitivity to external disturbances, and low stability. With increasing age, standardized survival numbers declined, mortality rates rose, and survival curves approximated the Deevey Type II pattern. Without intervention, the population is projected to face serious reductions as individuals age, potentially leading to extinction. Thus, we recommend minimizing human interference, implementing targeted protection strategies, increasing research and education, and promoting natural renewal through seedling propagation and artificial cultivation.

Abstract: This study explores the habitat distribution of Pterocarpus santalinus, a valuable rosewood species, across China, focusing on its response to current and future climate changes. Utilizing the MaxEnt model, we assess its suitable habitat under present conditions and future climate scenarios (SSPs126, SSPs245, and SSPs585). Our findings reveal that the current suitable habitat, spanning approximately 409,600 km², is primarily located in the central and southern parts of Guangdong, Guangxi, Fujian, Yunnan, as well as in the Hainan provinces, along with the coastal regions of Taiwan, and the Sichuan-Chongqing border. The habitat’s distribution is significantly influenced by climatic factors such as temperature seasonality (bio4), mean temperature of the wettest quarter (bio8), annual mean temperature (bio1), and annual precipitation (bio12), while terrain and soil factors play a lesser role. Under future climate scenarios, the suitable habitat for P. santalinus is projected to expand, with a northeastward shift in its distribution center. This research not only sheds light on the geoecological characteristics and geographical distribution of P. santalinus in China but also offers a scientific basis for planning its cultivation areas and enhancing cultivation efficiency under changing climate conditions.