Planting performance of natural hardwood species on a degraded site in the Liukuei area

Nine native hardwood species were enrichment planted in the Liukuei area, located in southern Taiwan, where there was a degraded site, considered to be difficult to reforestate because of shallow soils and long periods of dry weather in the fall and winter. The performance of growth and survival for these 9 species, and the occurrence and amounts of other tree species in this site including previous reforestated trees and naturally regenerating native trees, were investigated. Fraxinus formosana had the best seedling survival rate after planting for 1, 2, and 7 yr, while Alnus formosana and Cinnamomum kanehirae failed to survive. According to sapling survival, excluding poor seedling quality and silviculture practices, Acacia confusa had the best adaptability and the greatest height and DBH growth, while F. formosana was the second. Moreover, the branching rate on the trunk blow 1.3 m high of A. confusa was less than that of F. formosana. Among the previously reforestated tree species, the growth of C. camphora was better than that of other species. There were 23 tree species which naturally regenerated on the plantation, of which the Lauraceae and Fagaceae constituted the major tree species. The amount of Castanopsis formosana, a dominant species in this area, was the greatest. The biodiversity of this plantation at 32 species and 1195 individuals/ha thus increased, indicating that it is very important to investigate the potential banks of regeneration seedlings and seeds of native species originating from the disturbed land.