Abstract: We used typical sampling and community-ecology survey methods to study the plant community structure and species diversity of Amur linden(Tilia amurensis)-Korean pine(Pinus koraiensis) forest, Mongolian oak(Quercus mongolica)-Korean pine forest and Birch(Betula platyphylla) secondary forest in Heilongjiang Liangshui National Nature Reserve. There were 31 vascular plant species in Amur linden-Korean pine forest, belonging to 21 families and 25 genuses. There were 32 vascular plant species in Mongolian oak-Korean pine forest, belonging to 25 families and 28 genuses. There were 31 vascular plant species, belonging to 20 families and 28 genuses in Birch secondary forest. The species richness index S of tree layer and herb layer of Birch secondary forest were significantly higher than two kinds of broadleaved-Korean pine forest, and the shrub layer was lowest. Based on Simpson species diversity index, there was no significant difference between tree layers of three forest types, the shrub layer of Amur linden-Korean pine forest was significantly higher than the other two forest types, and the herb layers of three forest types were totally different. Based on Shannon-Wiener species diversity index, the tree layer of Amur linden-Korean pine forest was significantly lower than the other two forest types, and shrub layer of Birch secondary forest was significantly lower than the other two broadleaved-Korean pine forest, but the herb layer of Mongolian oak-Korean pine forest was highest. Pielou species homogenous index of tree layer of Mongolian oak-Korean pine forest was significantly higher than the other two forest types, there was no significant difference between shrub layers of three forest types, and the herb layer of Amur linden-Korean pine forest was lowest.

Key words: broadleaved-Korean pine forest, birch secondary forest, plant diversity, species diversity