Abstract:Lianas (woody vines) are an important component of tropical forests, with a strong impact on forest dynamics. However, the vertical structure of liana communities has been understudied. In the present study, the vertical distribution of liana (dbh≥0.5cm) abundance, species richness, size structure, climbing mechanism and species composition were investigated along eight ridge transects in a tropical montane rain forest in Bawangling Nature Reserve, Hainan Island. The results showed that, firstly, both liana abundance and species richness reach their peak at the intermediate height class. With increasing height class, more liana individuals distributed in the larger diameter classes. The individuals in diameter classes of 0.5-＜1cm and ≥2cm are dominant in the forest understorey and canopy, respectively. There are significant differences in stem proportion of different climbing mechanisms among different height classes. Stem twiner represent the chief mechanism in all height classes. The stem proportion of tendril climbers significantly decreases with increasing height class, while the stem proportion of root climbers increase with increasing height class. Species dominance ranking changes markedly with increasing height class. Generally, lianas show complex but ordered vertical structure patterns in this kind of tropical montane rain forest, and these patterns may determine their effects on forest dynamics.