Abstract: The effect of human activity on the ecosystem has become one of the hot topics in recent studies of ecology. However, few studies have investigated the comprehensive impact of cultivating trees on the ecological characteristics of local ecosystems. In this study, we used a sample method (quadrat investigation method) to compare ecological characteristics, such as life-form and leaf-size spectra, the composition of plant species, species’ richness and diversity, and floristic elements and biomass, of 12-year-old Betula alnoides in the pure forest and mountainous rain forest in southern subtropical mountain regions of Yunnan Province. Life-form and leaf-size spectra and floristic elements did not differ significantly between forest and mountainous rain forest. However, artificial forest had higher species richness than rain forest. The two kinds of forests had a similar Shannon-Wiener value (H'). The main species composition of B. alnoides in the forest was very different from that in the ountainous rain forest. So developing an appropriate area of artificial forest for local economy and vegetation restoration is necessary.