Abstract:Over the last century, human disturbance plays an important role in the change of global climate and environment and consequently, the loss of global species diversity. Unsustainable use of forest resources is causing dramatic changes in the forest communities and poses a serious threat to biodiversity worldwide. Plant species diversity is an index reflects the complexity and stability of forest community function. The effect of human disturbance on forest community can be directly reflected by the change of community structure and diversity. We hypothesize that community structure and plant species diversity vary with the different densities of human disturbance. In our study site in Jinfengshan Mountain, a tourism region located in Ya'an district, Sichuan Province, there are two major types of human disturbances: irrational selective cutting and tourism activities. In order to investigate the influences of different disturbances on the characteristics of species composition and diversity of Phoebe zhennan community in Jinfengshan Mountain, a field investigation was conducted. The intensity of human disturbance is divided into 3 levels: severe disturbance (close to the core scenic area within 40 m), medium disturbance (distant from the core scenic area at 40-80 m) and slight disturbance (far from the core scenic area at 80-120 m). The species richness index S, Shannon-Wienner index H, Simpson index D and Pielou index Jsw are adopted to evaluate the level of species diversity in Phoebe zhennan community. The results showed that 155 species, belonging to 36 families and 136 genera were found in 9 plots with a total area of 3600 m2. The following results were also revealed in this investigation: (1) the number of species decreased with the increase of disturbance intensity. (2) In terms of the community structure, the diameter and height class were normally distributed with slight and medium disturbance, significant difference in community structure was observed among communities with three different disturbance intensities. Individuals under slight and medium disturbance were distributed in small and medium diameter class(4 < DBH < 20 cm), and low and medium height class(5 < H < 13 m). Individuals in severe disturbance were mainly distributed in small diameter class(DBH < 8 cm) and big diameter class(DBH≥28 cm), and low height class(3 < H < 7 m) and high height class(H≥15 m). (3) The species diversity indexes generally exhibited slight disturbance > medium disturbance > severe disturbance respectively. The richness index S, Shannon-Wienner index H and Pielou index Jsw were decreased with the increase of human disturbance intensity. This study suggests that human disturbance had negative effects on the diversity and stability of Phoebe zhennan community, which calls for urgent actions to solve the conflict between human disturbance and the protection of species diversity. "Close to nature" forestry, a theory about sustainable forest management which integrates consideration of social, economic, and environmental factors in decision making is proposed to be taken into practice in this study area.