Abstract: Based on field survey and document information, and combining with climate data, the biogeographical significance of flora transition and its correlations with climate factors were examined, and in terms of the biogeographical significance, the vegetation regionalization in eastern China was explored. The results showed that the ratio of tropic flora component to temperate flora component (T_trop/T_temp) had significant negative correlations with altitude and latitude, and thus, the flora transition could be estimated by the regressive equation among them. When the flora transition was constant, the altitude decreased against latitude. With increasing mean annual temperature, the flora transition increased first and decreased then, representing a hump-shaped pattern. Through the analysis of the relationship between flora transition and mean annual temperature, the boundaries between tropic rain forest and southern subtropical evergreen forest, between northern subtropical evergreen-deciduous mixed forest and warm temperate deciduous forest, and between cool temperate deciduous forest and temperate needle forest in eastern China were the south of 21.5°N and the north of 34°N-35°N and 47.5°N, with the mean annual temperature of 23.40 ℃, 12.45 ℃, and 1.51 ℃, respectively, which was consistent with the previous studies. This study provided a new idea and methodology in exploring the spatial variation of flora transition and the geographical distribution of vegetation in eastern China.

Key words: Artificial seabuckthorn forest, Loess hilly region, Soil and water conservation, Mechanism