Uniqueness and Contributing Factors of Main Tree Species Distribution in Kunyu Mountain

Located in a transitional climatic zone surrounded by sea on three sides, Kunyu Mountain provides an ideal region to study the drivers of plant distribution. The study examined the distribution patterns and environmental drivers of three dominant tree species—Pinus densiflora, Cunninghamia lanceolata, and Pinus koraiensis—using data from 55 permanent plots. A total of 52 plant species were recorded, primarily in warm-temperate areas, with some in other climatic zones. While the native P. densiflora was widespread, the introduced C. lanceolata and P. koraiensis showed limited distribution, with lower richness and growth rates than in their core ranges, yet both regenerated naturally. C. lanceolata mainly occurred below 400 m on sunny slopes, whereas P. koraiensis was concentrated at 400–500 m on shaded slopes. Climate similarity analysis confirmed that local microhabitats created by transitional climate and complex topography offer suitable conditions for both species. These findings improve the understanding of microhabitat roles in species distribution and offer insights for future species introduction strategies.