Abstract:In order to understand the structure and regeneration mechanism of dominant species in community, the evergreen and deciduous broad-leaved mixed karst forests in Maolan National Nature Reserve, Guizhou Province, were investigated. The results showed that there were 70 woody species, belonging to 37 families and 58 genera in the community. The dominant families were Lauraceae, Rosaceae, Sapindaceae and Aceraceae. There were 41 evergreen trees and 29 deciduous trees, accounting for 58.6% and 41.4% of the total species, respectively, which indicated the character of evergreen and deciduous broad-leaved mixed karst forests. The dominant trees in community were Litsea verticillata, Cyclobalanopsis glauca, Machilus rehderi and Cladrastis platycarpa, etc., while dominant shrub were Pittosporum crispulum, Euonymus dielsianus, Sinosideroxylon wightianum and Nandina domestica, etc. Based on DBH class distribution pattern, the dominant species community structure could be divided into five types. The unimodal type species, such as heliophyte Cerasus pseudocerasus and Choerospondias axillaris, regenerate in gap, which would disappear finally with the gap closing. The inverse-J type species, such as evergreen broad-leaved trees Litsea verticillata, Dendrobenthamia hongkongensis, Pittosporum crispulum, were dominant species in climax community with strong shade tolerance and renewability. The sporadic type species, such as Cyclobalanopsis glauca, Machilus rehderi, Clausena dunniana, main in small DBH class, can exist in the community for a long time. The L type species, such as Cinnamomum tamala, Acer catalpifolium, Sinosideroxylon wightianum, and the unibar type species, such as Mallotus repandus, Nandina domestica, were the dominant species in subtree layer and shrub layer of the climax community. Therefore, the karst forest community in Maolan is in a relatively stable climax stage.
