The Effects Of Lianas On The Regeneration Of Lowland Secondary Forest In Bawangling Nature Reserve, Hainan Island

Lianas (woody vines) are an important component of forests, especially in tropics. They strongly influence regeneration of trees and maintenance of species diversity in tropical forests. In many tropical forests, lianas compete with trees, which compete aggressively for resources and thus may limit tree growth and affect the community structure. Lianas were found to play a vital role in many aspects of forest dynamics in the Bawangling Nature Reserve, Hainan Island, including suppressing tree regeneration, increasing tree mortality. We explored the effects of lianas on the regeneration of lowland secondary forests and estimated the effects of lianas on the regeneration and structures of tropical forest lowland secondary forest in Bawangling Nature Reserve.In order to survey the effects of lianas on the establishment of seedlings, we investigated the seedlings in a natural lowland secondary forest. We also investigated tree and lianas (DBH≥1cm in diameter) in five transects from the plantations to study the effects of lianas on the community structures and tree regeneration.Establishment of seedlings in the secondary forest was restrained with the dense lianas cover and different competition regions. Mean height of seedlings was not affected by the liana cover and competition styles. The abundance of tree seedlings was sharply reduced in the SC and AC with the dense lianas cover, however, there was no difference between the SC and AC. The richness of tree seedlings was reduced more sharply in SC than in AC and NC.The seedlings and saplings species were changed with the increasing liana density. Seedlings in low lianas density Vatica astrotricha plantation such as Psychotria rubra, Elaeocarpus dubius have higher abundance compared with the high lianas density plantation. However, Seedlings in low lianas density Camellia oleifera-Cunninghamia lanceolata plantation such as Psychotria rubra, Symplocos cochinchinensis, and Nephelium lappaceum have higher abundance compared with the high lianas density plantation. Seedlings lower than 15cm in the low lianas density Vatica astrotricha plantation have higher abundance compared with the high lianas density plantation. The abundance of seedlings in different height classes of high liana density Camellia oleifera-Cunninghamia lanceolata plantation decreased significantly. Saplings in different diameter classes in both high liana density plantations have high abundance than it in low liana density plantation.The community structure and diversity characteristics of both the plantations were analyzed. The results showed us,82 species belonging to 63 genera and 38 families and 65 species belonging to 51 genera and 35 families were recorded in the high and low liana density Vatica astrotricha plantations respectively.However,80 species representing 59 genera and 40 families and 58 species belonging to 47 genera and 31 families were recorded in both Camellia oleifera-Cunninghamia lanceolata plantations. Tree abundance is higher in the low liana density Vatica astrotricha plantation, there are no significant difference in tree mean height and tree basal area, but there are no significant difference in tree mean height and tree basal area in both Camellia oleifera-Cunninghamia lanceolata plantations. Tree abundance (1cm