Tree Species Selection for Mixed Forest Planting to Transform Secondary Stands of Acacia mangium

12 studied tree species were divided into three categories by cluster analysis on investigated data of the basal diameter, tree height and crown width of the seedlings.The first category was fast-growing tree species including Albizia falcate and Swietenia macrophylla.The second category was tree species with medium growing speed including Acacia holosericea, Acacia auriculaeformis, Schima superba and Castanopsis hystrix.And the third category was slow-growing tree species including Castanopsis fissa, Liquidambar formosana, Acer buergerianum, Schefflera octophylla, Cinnamomum burmanii and Erythrophloeum fordii.Analysis of chemical properties of soils sampled from 9 plots indicated that the organic matter contents were medium in all of the plot soils, contents of the total N as well as the alkalized N were medium in most of the plot soils, whereas the contents of the total P, available P were very low and the total K and available K were generally low in all of the plot soils.